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 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924072684529 
 
3 1924 072 684 529 
 
GEOLOaiCAL SURVEY OF CAJNAUA 
 
 ROBERT BELL, M.D., ScB. (Cantab), LL.D., F.R.S. 
 
 REPORT 
 
 CAMBRIAN EOOKS 
 
 CAPE BRETON 
 
 G. F. MATTHEW, LL.D., D.Sc, F.R.S.C. 
 
 OTTAWA 
 
 PRINTED BY S. E. DAWSON, PRINTER TO THE KING'S MOST 
 BXCETXENT MAJESTY. 
 
 1903 
 
To Robert Bell, M.D., Sc.D., F.R.S., etc., 
 
 Director Geological Survey of Canada. 
 
 SiE, — I have the honour to submit herewith my report on the special 
 work, undertaken at the instance of the late Director of the Survey, 
 on the Cambrian area in Cape Breton, N.S. This work, begun in 1899, 
 has been delayed by the shortness of time at my disposal for investi- 
 gation each year, making it necessary for me to revisit the island to 
 complete necessary observations. 
 
 I am, sir. 
 
 Your obedient servant, 
 
 G. F. MATTHEW. 
 
 1^ 
 
EEPORT 
 
 CAMBRIAN ROCKS OF CAPE BRETON 
 
 In the spring of 1899 I received the following letter from the late Instructions 
 Dr. G. M. Dawson, at that time Director of the Canadian Geological m°'d?wsot. 
 Survey : — 
 
 ' Deae Dr. Matthbv/, — In thinking over work for the coming 
 summer it occurs to me to ask whether it would be agreeable to you 
 to undertake a field examination, for such time as you could spare, of 
 the Cambrian rocks in Cape Breton island, followed subsequently by 
 such study of the fossils obtained as might be necessary for their 
 determination and description. We seem to know very little about 
 the Cambrian and possible Cambro Silurian rocks of Cape Breton, 
 although Mr. Fletcher, on stratigraphical grounds, seems to think that 
 there is a great thickness, which may represent a number of horizons.' 
 
 These clauses of Dr. Dawson's letter seemed to present to me the 
 kind of investigation which he wished made in Cape Breton, and were 
 taken as directive of the work which I subsequently arranged with 
 him to do there. The short tiuie at my disposal in three succes- 
 sive summers was given to this exploration, and intervals of leisure 
 during the three years have been spent in working up the results of 
 the field exploration. • _ 
 
 I was guided by Mr. Hugh Fletcher in selecting areas where it was Mr. Hugh 
 thought the best results could be obtained, and for this reason my assistance. 
 work was confined to the Barachois basin on St. Andrews Channel, to 
 Indian Brook basin and several smaller areas on East Bay, and to the 
 most important parts of the valley of the Mira river. There are some 
 other small areas of Cambrian rocks in the island of Cape Breton, but 
 these Mr. Fletcher did not think would yield results such as I sought, 
 and so they were not visited. 
 
 The object of my visit then was to study the thickness, succession 
 and distribution of the several members of the Cambrian system ; and 
 
to collect and determine the fossils which they might be found to con- 
 tain. In thus ascertaining the relation of the several parts of the 
 Cambrian terranes to each other, and their distribution, a guide would 
 be had also to the location of mineral deposits which the Cambrian 
 rocks might contain. 
 
 INTRODUCTORY. 
 
 THE STRUCTURE OP THE CAMBRIAN ROCKS IN CAPE BRETON, AND THEIR 
 CONTAINED FAUNAS. 
 
 Knowledge of Since the survey of the Cambrian areas in Cape Breton was made 
 svrtem *" ^^ ^^- Hugh Fletcher some twenty-five years ago, our knowledge of 
 extended. the Cambrian system in America has been greatly extended, notably 
 by the explorations of the United States Geological Survey, and 
 through the efforts of its present able director. Much also has been 
 done by the Canadian Survey, especially in the region of the Rocky 
 mountains, the valley of the St. Lawrence, and in Labrador. 
 
 In the province of New Brunswick the structure and faunas of the" 
 Cambrian rocks have been worked out by private effort, and from their 
 proximity to Cape Breton are most reliable for comparison with those 
 of that island. The series there also is so complete that it yields a 
 good standard of comparison for all the Atlantic coast Cambrian 
 deposits. 
 
 Earlier .survey After the exploratory work of the Canadian Geological Survey had 
 Fletcher. been opened in Cape Breton, Mr. Fletcher, in 1874, began the study 
 of the areas where the Cambrian rocks are found, and continued his 
 work there for three years, when the further prosecution of the sur- 
 vey carried him beyond the Cambrian areas. 
 
 In the progress of Mr. Fletcher's work in the Cambrian districts he 
 had found that the sediments of this age lie in several narrow valleys 
 inclosed between abrupt hills of Pre-Cambrian rocks, mostly crystal- 
 line or metamorphic ; and in one broader valley, that of the Mira 
 river. It was in the valley of this river that the fossils were found, 
 which determined the Cambrian age of the above mentioned rocks in 
 Cape Breton. 
 
 The carefully delineated topographical details given by Mr. Fletcher 
 in his excellent maps, the record of the dips and strikes of the rocks, 
 of the nature of the sediments, and of the localities where fossils were 
 to be had, materially aided the writer in investigating the geology of 
 
this district. The writer would also acknowledge valuable personal 
 assistance from Mr. Fletcher, rendered at the instance of the Director 
 of the Survey. 
 
 In addition to the geological map of Cape Breton, on which the References to 
 Cambrian areas are depicted, references to the Cambrian rocks of the roXs?"^'^" 
 island by Mr. Fletcher will be found in the Reports of Progress of the 
 Geological Survey, year 1875-6, pages 389 to 393 ,■ year 1876-7, pages 
 428 to 437 ; and year 1877-8, pages 11f to 16f. In these reports the 
 rocks are described under the head of Lower Silurian, as at that time 
 the Cambrian was not fully recognized in America as a system with 
 distinctive faunas separate from the Lower Silurian. 
 
 Mr. Fletcher explored two narrow valleys of Cambrian rocks on St. 
 Andrews channel, connected with the Boisdale hills, and two others 
 on East bay, in the Coxheath hills. In all these he found the strata 
 highly inclined, and in many of his notes only the strike is recorded. 
 In the larger Cambrian district on the Mira river also, the strata dip 
 at a high angle, so that the structure cannot be inferred from the de- 
 tails given. Thus the structure and succession of the beds could not 
 be determined without some further study in the field. I therefore 
 gave some attention to the distribution of the strata before collecting 
 materials for the study of the fossils. This preliminary work was of 
 importance as it enabled me to place one of the faunas at a horizon 
 lower than the biological indications had warranted. 
 
 CAMBRIAN STANDARDS. 
 
 The standards used for comparison of the faunas are those of Great Cambrian 
 Britain and Sweden. In the lower members of the Cambrian deposits Sweden. 
 of Sweden the faunas are poor and wanting in variety, but the Middle 
 and Upper Cambrian have a full and rich succession of faunas. The 
 richness of the Cambrian faunas of Sweden in trilobites allows of very 
 exact and minute distinctions between the several layers, so that the 
 succession groups have been distinguished by the several faunas which 
 they contain ; and we also have an upward succession of groups each 
 distinguished by a leading genus of trilobites, or other organism, as : — 
 
 Olenellus fHolmia) fauna. 
 Lower Paradoxides beds. 
 Upper Paradoxides beds. 
 Olenus beds or fauna. 
 Peltura beds or fauna. 
 - Dictyonema fauna. 
 
Cambrian 
 system in 
 Wales. 
 
 First 
 
 classification 
 of the 
 Cambrian 
 in New 
 Brunswick. 
 
 The Ceratopyge fauna which follows, and which is equivalent in age 
 to the Tremadoc slates of Wales, is considered by the Swedes and 
 Germans to be a part of the Ordovician, or Lower Silurian system. 
 
 In Wales there is a great development of the Cambrian system, the 
 thickness from detrital sources being increased by additions of 
 volcanic ashes and lava. 
 
 The original work of the Geological Survey of Great Britain in this 
 district, especially in the south of Wales, has been greatly extended 
 and improved upon by the late Dr. Henry Hicks, to whom we are 
 largely indebted for the elaboration of the several groups which make 
 up the Cambrian system in that principality and for the description of 
 their faunas. His classification from the base upward is as follows : — 
 
 Caerfai group, including the Olenellus zone. 
 
 Solva group : this by its fossils belongs to the Lower Paradoxides 
 beds. 
 
 Menevian group : this also contains Lower Paradoxides species, 
 the Upper Paradoxides fauna has not been definitely recog- 
 nized in Wales. 
 
 Maentwrog group — Olenus fauna, 
 
 Ffestiniog group, with Lingulolla Davisii, &c. 
 
 Dolgelly group, with Parabolina, Peltura, (fee. The summit of this 
 is equivalent to the Dictyonema shale of Sweden. 
 
 Tremadoc group; this contains the genera Niobe and Asaphellus, 
 and is equivalent to the Ceratopyge fauna of Sweden.* 
 
 These standards have already been applied to the Cambrian rocks 
 in New Brunswick, where most of the faunas referred to above have 
 been recovered and the lithological aspect of the strata in which they 
 exist has been noted j so that there was now a standard more acces- 
 sible to the Canadian geologist, and comparatively close to the pro- 
 posed field of exploration, and a district where lithological resemblances 
 may be supposed to have a more definite value. 
 
 The lithology of the New Brunswick Cambrian beds had been 
 studied and described before any fauna except that of the Lower 
 Paradoxides beds was known in them, so the terms used in desi^na- 
 tion the several groups of strata in this system in New Brunswick are 
 based on their lithological aspect. Hence we have the following : 
 
 * Fauna of Olenellus zone in Wales. Geol. Mag., London, 1892, p. 21. 
 
9 
 
 Division 0. 
 
 a. Red conglomerate. 
 
 b. Red and green sandy slates. 
 Division 1. 
 
 a. Coarse gray sandstone or quartzite. 
 h. Coarse gray sandy slate. 
 
 c. Pine gray and dark -gray slaty shales. 
 
 d. Fine black carbonaceous slaty shales. 
 
 The two last contain the Lower Paradoxides fauna of Sweden. 
 Division 2. 
 
 a. Dark-gray slates with seams of gray sandstone. 
 
 h. Coarse gray slates and gray flagstones. 
 
 c. Gray sandstones and coarse slates (Linguloid shells). 
 Division 3. 
 
 a. Dark gray finely laminated slates. 
 
 h. Black carbonaceous and dark gray slates, less fissile than the 
 last.* 
 
 Two other divisions were described, bu t these were found to be repe- 
 titions of those of Division 3. When the faunas of Division 3 were 
 studied the latter was found to contain a number of faunas which 
 were designated by the additional letters c, d and e, the two last 
 mentioned being Ordovician. 
 
 After eliminating from the described rocks of the Cambrian areas C^ape Breton 
 in Cape Breton some which are Pre-Canibrian, it is not at all difficult similar to that 
 to recognize this entire series of deposits in the Cambrian succession g. ". j. 
 of that island. The known fossiliferous beds of the island were Upper 
 Cambrian, and the others, by their position relative to these, represented 
 the middle and lower part of the St. John series. The confirmation of 
 this view suggested by the lithological appearancs of the beds was 
 obtained when the faunas were collected and studied. 
 
 The study of the faunas of the St. ,fohn group, begun in 1881, was 
 not completed until twelve years thereafter, but as the palaeontology 
 unravelled itself, it was found to be in close accord with what had 
 been determined as to the Cambrian succession in Europe. 
 
 *Illustrations of the Fimna of the St. John Group. Trans. Roy. Soc. Can., vol. 
 I., sec. iv., p. 88, 1882. 
 
Fauna of St. 
 John group 
 in New 
 Brunswick. 
 
 10 
 
 Thus the following faunas of trilobites and graptolites were found 
 in the St. John group, which comprises the Divisions 1, 2 and 3 
 indicated above. 
 
 Division 1. 
 
 h. Fauna of Protolenus (not known in Europe). 
 
 c ) 
 
 , > Various sub-faunas of the Lower Paradoxides beds. 
 
 Division 2. 
 
 No trilobite faunas were found. 
 Division S. 
 
 a. Fauna of Parabolina. 
 
 b. Fauna of Peltura. 
 
 c. Fauna of Dictyonema (graptolite). 
 rl. Fauna of Tetragraptus (graptolite) and the trilobite Cyclogna- 
 
 thus. 
 
 The fauna of Protolenus, not known in Europe, is found in New 
 Brunswick and Newfoundland, below Paradoxides, but the other 
 faunas follow the same succession in Europe. It also became clear 
 from these discoveries that the uppeimost pa,rt of the St. John group 
 was not Cambrian but Ordovician, or Lower Silurian, and that the 
 recognizable Cambrian part terminated with the Dictyonema fauna, 
 but included that of Protolenus. 
 
 The faunas of both b and c in Division 3 had already been found in 
 Cape Breton, so there was a reasonable hope that, in the underlying 
 part of the Cambrian in that island, the faunas of- the corresponding 
 portion of the St. John group would be found on further study of the 
 field and this hope has in part been realized. 
 
 As the faunas and the lithological succession of the several divisions 
 of the St. John Group did not agree in all respects with the European 
 strata in New Cambrian it was thought advisable in 1890 to give them local names, 
 and hence : — 
 
 Division 1, in which the first characteristic Cambrian fauna was 
 
 found was called Acadian, 
 Division 2, which is very fully developed in the city of St. John, 
 
 was called Johannian, and 
 Division 3, whose faunas were first distinguished in Cape Breton, 
 
 was named Bretonian.* 
 
 Kegional 
 names of the 
 Cambrian 
 
 Brunswick. 
 
 *Trans. Roy. Soc. Can., vol. viii, sec. iv, p. 129, 1S90. 
 
11 
 
 These names are used in the following report. 
 
 Since the conclusion of his work on the St. John group, the writer 
 has been engaged in studying and developing the faunas of the 
 Division ' ' of the classification given in 1882 for the St. John 
 Cambrian. This division proved to be of much greater importance 
 than it appears to have in the St. John section, and its extension 
 eastward was studied in connection with that of the St. John group. 
 At the eastern end of the St. John basin of Cambrian rocks a full 
 exposure of its measures was found, where it exhibited two divisions 
 with a conglomerate bed between, but the few organisms obtained 
 were not of a sufficiently high order to afford any definite means of 
 comparison with the faunas of other countries. Considerable time 
 was given to the examination of these measures in 1888, and it was 
 then spoken of as the Basal series.* 
 
 Observations on this part of the Cambrian system were continued Regional 
 in the island of Newfoundland, where it was found to contain fossils Etelfeminian"" 
 in better preservation and greater variety. The findin" of a dis- *°l the oldest 
 tinctive fauna in this group of beds in ^' ewfoundland made it advis- s^'imSft' 
 able to give it a distinctive name, as has been done with the several Bmnswiek 
 divisions of the St. John group, and it was called Etcheminian. The =*°'l ^'•'^- 
 observations made during the past three seasons in Cape Breton have 
 served greatly to enlarge our knowledge of this portion of the Cam- 
 brian. 
 
 It is proposed to describe the distribution and thickness of the 
 several groups of Cambrian strata, above defined, as they appear in 
 Cape Breton, but before doing so it will be desirable to refer to two 
 other groups which underlie them, one of which, the Coldbrook, is 
 closely connected with the Etcheminian. The other is an entirely 
 different and much older series. 
 
 PART I.— STRUCTURAL GEOLOGY. 
 
 TERRANES REPRESENTED IN THE CAMBRFAN SYSTEM IN CAPE BRETON. 
 
 When the writer began the study of the Cambrian system in Cape 
 Breton (represented on the geological map as Lower Silurian), he found 
 that one series of rocks comprehended in the section coloured as Silurian, 
 was remarkably like the ' Upper Series ' of the Laurentian area near 
 St. John. An examination of the exposures of these beds at Long 
 
 *Trani=. Royal See. Can., vol. vii, sec. iv, p. 135, 1889. 
 
A pve-Cam- 
 brian system 
 eliminated 
 from the 
 Cambrian of 
 Cape Eieton, 
 
 12 
 
 island in St. Andrew's channel and at McLean point to the south-west 
 of Long island (the west point of Barachois harbour) convinced him that 
 this resemblance was not accidental, and that the series bore the 
 same relation to the Cambrian that the resembling beds in St. John 
 county, New Brunswick did. This conclusion was confirmed by ob- 
 servations on Indian brook, where similar rocks were found to bear 
 the same relation to the eff'usives which underlie the Etcheminian. 
 
 This series as seen on Long island consists of dark gray limestone 
 with layers of calciferous schist, frequently alternating, and dolomitic 
 limestone, having beds of dark gray to black silicious schist, also dark 
 gray feldpathic schist. At McLean point the same limestones are 
 seen in a much less altered condition, and on the road further south-west 
 black flinty shales occur. Similar rocks occur at McSween brook. 
 Other exposures of this series are met with at McLean brook, Shen- 
 acadie, where the section ccurs described by Mr. Fletcher in the 
 Report of Progress, 1876-77, page 431. 
 
 Beside their resemblance to the ' Upper Series ' of the Laurentian 
 in St, John county, this group is thought not to be Cambrian for the 
 following reasons : — 
 
 1. No similar series has been met with by me in the Cambrian rocks 
 
 of Cape Breton or elsewhere. 
 
 2. They are cut by granitic veins ; the Cambrian is not. 
 
 3. Similar rocks in the Indian Brook district have furnished pebbles 
 
 to the Cambrian conglomerates. 
 
 4. These rocks are cut by red granite which has also furnished pebbles 
 
 to the Cambrian conglomerates. 
 
 I conclude therefore that this group should be detached from the 
 Cambrian, and should probably go with the George river limestones. 
 
 THE CAMBRIAN SYSTEM. 
 
 THE COLDBROOK TERRANE. 
 
 The Cold- The relation of this terrane to the Laurentian Upper Series below 
 
 brook terrane. j^jj^ ^^ ^j^g overlying sedimentary Cambrian, are well shown at Long 
 island in St. Andrews' channel. 
 
 Here along the north-western shore of the island the contact 
 between these effusive rocks and the metamorphic ' Upper Series ' is 
 visible. The lower layers of the Coldbrook are gray ash rocks, more 
 
13 
 
 or less vesicular and calcareous. Resting upon these ash rocks and 
 seen on the road to the ferry, is a mass of red felsites, showing flow- 
 lines, etc, some of which are quite ferruginous and rusty-looking. 
 Above the red felsites are fine-grained dark-gray felsites which in turn 
 support the gray grits and sandstones of the marine Cambrian. 
 
 The red felsites at the Ferry road dip S. 55° E. mag. < 30-40°. 
 Further east on the island, they dip in the same direction at a higher 
 angle, and all along the eastern shore of the island the dip of the 
 felsites conforms in a general way to that of the overlying Cambrian 
 marine beds. 
 
 From the south-west end of Long island, across and beyond Break in 
 Barachois harbour, there is a break in the range of Coldbrook effusive ColdbTOok 
 rocks that borders the north side of the Barachois basin. This break effusives, 
 is partly the space occupied by Barachois harbour and partly the 
 ridge opposite Barachois pond, which is of Lower Carboniferous 
 conglomerate and sandstone. But near the mouth of McLeod brook, 
 which enters the head of this pond, the effusives again come into view. 
 Here they consist of dark gray amygdaloid al diabase, holding cavities 
 filled with calcite, and having intercalated beds of water-washed 
 felsitic sand, containing small oval fragments of soft black slate. At 
 one point the bedding has a dip of < 30°. 
 
 There must be a profound fault here with a downthrow to the south, 
 as the floor of the valley of McLeod brook is occupied by the 
 dark-gray shales or slates of the Bretonian division of the St. John 
 terrane. 
 
 The Coldbrook rocks were again found further up this valley, on the 
 north side, where the Bourinot road crosses the ridge between the 
 valley and St. Andrew's channel at Boisdale. On this road the crest 
 of the ridge is of preCambrian syenite or quartz-diorite, but where 
 the road begins to descend towards the valley of McLeod brook, this is 
 overlaid by dark-gray effusive rocks, some of them compact, with 
 tabular crystals of feldspar, others more vesicular, with calcite in the 
 cavities. A third variety shows pebbles of brown and red felsite in a 
 dark feldspathic paste. At the southern edge of these effusives there 
 is some purplish gray slate. 
 
 A band of coarse-grained quartz-diorite then intervenes, separating Coldbrook 
 
 ° ' • 1 u u ^ effusives along 
 
 the above effusives from another belt running along the brow of west sidR of 
 
 McLeod brook valley. These show dark-gray, somewhat purplish- ^^^ "'^ 
 
 weathering amygdaloid, having vesicles of calcspar, and are seen after 
 
u 
 
 passing the corner of the Boisdale-Bourinot road. On this road they 
 appear at intervals at several localities to the point where the road 
 descends into the valley of McLeod brook. 
 
 Mr. Fletcher's report 1876-77, page 429, (last paragraph) would in- 
 dicate that there is a considerable manifestation of these rocks and the 
 over-lying conglomerates at the sources of McLeod brook and Indian 
 brook which meet in the upper part of this valley. 
 
 For its whole length the Barachois Cambrian basin from George 
 river station to the source of McLeod brook, is bordered on its southern 
 side by a prominent ridge of Pre-Cambrian syenite. Southward of 
 Long island ferry these rocks reach the water in Barachois harbour, 
 and hence to the head of McLeod brook we see no Coldbrook or 
 Etcheminian rocks on that side of the valley. At Barachois harbour 
 flags and slates of the Johannian division of the St.John terrane lie 
 along the base of the granite ridge, but from the harbour to the head 
 of the valley of McLeod brook no rocks were seen but those of 
 the Bretonian division of the same terrane. It may be inferred that 
 there is a heavy fault along this side of the valley by which the Cold- 
 brook and the overlying terranes have been depressed, and only the 
 highest part of the Cambrian is visible along the base of this ridge in 
 McLeod brook valley. 
 
 Coldbrook In the vallev of Indian brook on East bay of the Bras d'Or lake, 
 
 +-py»-*ift Yip liT 
 
 valley of volcanic effusives intervene in the same way as in the valley of McLeod 
 
 Indian brook. 13j.qq]j between the Laurentian ' Upper Series ' and its intrusive rocks, 
 
 and the marine Cambrian. They are seen on all the small brooks 
 
 tributary to that stream, but are exposed in their entire thickness on 
 
 Dugald brook. (See map opposite.) 
 
 Here the lower half consists of material more or less water-worn ; for 
 the most part a feldspathic sandstone with irregular layers of conglo- 
 merate. The latter have rounded pebbles, some of felsite and others 
 of granite ; the conglomerates are not thoroughly water-worn and have 
 a paste largely feldspathic. This half of the Coldbrook strata is capped 
 by thirty feet of fine gray shale with fossils. These shales, in their 
 slicken sided surfaces and distorted fossils, give evidence of the greater 
 disturbance and pressure applied here than to the Etcheminian shales 
 of the next terrane above. Some layers have numerous though small 
 phosphatic nodules. 
 
 The shales are succeeded by red and purple earthy felsites, and 
 higher by purplish and purplish-gray amygdaloids. These felsites and 
 amygdaloids seem to take the place in this section of the red felsites of 
 
=.'-'..'''-■- Gnej-SysnitZ /liUs- 
 
 
 -■/Tz^rzz:^ etc. 
 
 '•my^'^'"_"}'^''*Base ^Xin^emirzuzn. 
 
 =r--^=&2)».»"<w';" 
 
 terrane. 
 
 \., 3a^al can^torjtemie 
 
 «::;wr„,;.„ -?.'■ - •■" ^St.Jo7u7.terrane. 
 
 GORGE OF DUGALD BROOK 
 Scale BOO/ketto 1 U7cA 
 
Long island described above. Mr. Fletcher in the Report of Progress 
 for 1876-77 at page 413 gives a section of the rocks on this stream. 
 
 Coldbrook Jq the valley of the Mira river the Coldbrook terrane appears in 
 
 in valley of great force. At McCodrum hill on the Morley road, one meets with 
 
 1 ira uvei. ixmcij felsite breccia at the top of the hill and on the slope toward the 
 
 Mira river. It consists of, first a dark gray, white-weathering felsite, 
 
 then felsite of a brick-red colour whose fragments have been scattered 
 
 by glacial action over the low lands of the Mira valley to the south. 
 
 On the opposite side of the Mira valley are extensive exposures of 
 the Coldbrook effusives. Bengal settlement is located on these rocks 
 and towards its eastern end at the road, there are considerable expos- 
 ures of red breccia-grit having a purplish-red paste with imbedded 
 angular fragments cf gray felsite. 
 
 Large area of The extent of these I ocks south of the road was not ascertained, but 
 
 fehites east (jf 
 
 Mira river. they extend 200 yards north ot the road, across the stnke, and dip 
 
 N. 30° W. mag. <60\ and are overlain in that direction by greenish- 
 gray, white weathering, and red-weathering schistose felsite, having 
 a few small angular fragments of felsite imbedded, witt the same dip 
 as the breccia grit nearer the road. The upper felsftes, 200 yards north 
 of the Bengal road, would correspond to the red felsites of McCodrum 
 hill in age, and are overlain by the next terrane, the Etcheminian, which, 
 where its measures are exposed along the base of these efiusives two 
 miles to the west on the Bengal road, dips N. 50° W. mag. < 80°. 
 
 Mr. Fletcher's reports show that from the valley of the Mira river 
 to the Atlantic coast, and along this coast from Scatari island to 
 Forchu bay and Framboise, there is an extensive tract occupied by 
 felsites an 1 breccias, anl it may be surmised that this was an import- 
 ant centre of eruption in Coldbrook time, such a centre as, in the 
 province of New Brunswick, existed in the eastern part of St. John 
 county. The great mass of diorites, felsites and amygdaloids forming 
 the Quaco hills of that district have been described by Dr. L. W. Bailey 
 in Report of Progress 1877-78, pages 10 dd. to 21 dd.,&c. 
 
 Fossils in the The only place where this terrane was observed to be fossiliferous 
 
 Oold brook at -r-* i i i 
 
 Dugald brook, was at Dugald brook, a branch of Indian brook on East bay ; the sec- 
 tion on that brook is described in connection with the following 
 terrane. 
 
 THE ETCHEMINIAN TERRANE. 
 
 A long narrow basin of Cambrian rocks extends from George river 
 station to the head of McLeod brook, past Barachois station and harbour 
 
17 
 
 on St. Andrews channel. The Etcheminian terraae is exposed at the 
 north-east end of this basin, but the structure is complicated by faults 
 and folds. 
 
 At George river station is the north-eastern end of a long ridge of 
 syenitic rocks which extend the whole length of the basin, bordering 
 it on the south-eastern side. The basal conglomerates of the Etche- Basal 
 minian are wrapped around the north-eastern end of this ridge, and rf°|^°""^''*'® 
 around the corresponding end of Long island. On this island, howe- Etcheminian 
 ver, they rest on Coldbrook felsites and breccias, and no syenite is basi^.'^" ™* 
 visible. In the railroad cuttings at George river station the contact 
 of these conglomerates with the syenite can be seen at several places. 
 They fill hollows in the syenite and dip N. mag. and N. 20° E. mag. 
 < 60°. Felsite boulders are common in these conglomerates. 
 
 Westward of the station and beyond a brook and an embankment, 
 the conglomerates are seen to rest on dark purplish-gray fine-grained 
 felsite similar to those of I-ong island and presumably of the Coldbrook 
 terrane ; one bed has boulders six inches to two feet in diameter, of 
 dark purplish-red felsite, some of which are quite siliceous. This is 
 followed by fine-grained earthy felsite with crystals of kaolinized 
 feldspar, showing ancient weathering. With these conglomerates is a 
 hard purplish-red slate, and a compact feldspathic rock seamed with 
 epidote. The dip here is N. 10° W. mag. < 85° ; but the prevalent 
 dip in the cutting is to the S.S. W. 
 
 Off the railroad track one hundred yards to the south-west is a mass 
 of gray slate, etc., which would seem to be the upper division of the 
 Etcheminian terrane. Here the railroad track begins to turn to the Associated 
 south, and after passing a space of about eight hundred feet, one sandstones 
 comes to purplish-red slates and purplish- gray sandstones of the lower 
 division of the Etcheminian. The cleavage planes here dip N. 55° E. 
 mag. < 90°, but the dip of the beds is N. 5° W. mag. < 50°. The 
 shaly layers below the sandstones have a few Lingulellas, not well 
 preserved. These beds are capped by Lower Carboniferous limestone 
 extending to the shore. 
 
 At Young's brook just beyond this hill, these red slates and sand- 
 stones are cut off by a fault, and the rocks which appear to underlie 
 them are gray. These show on the shore and along the railroad track 
 and are the base of the upper division, which extends thence along the 
 west side of the valley of Young's brook to the highway and beyond. 
 The valley itself and its eastern side up to the syenite are occupied by 
 dark -gray slates &c., a portion of the St. John terrane. The purplish 
 coarse gray slates west of Young's brook in the railway cutting dip 
 2—0. E. 
 
18 
 
 S.E. mag. < 40° and have sandstone beds with much felsite sand, 
 and with some pebbles of red felsite and of black siliceous slate. Else- 
 where in this cutting the dip of the beds is S. 20° E. mag. < 60° and 
 the hade or slope of the cleavage N. 70° W. mag. < 85°. These 
 sandstones hold a Lingulella similar to L. Selwyni. 
 
 Westward of this on the railway there is a space of 1,100 feet 
 without exposures, and thin cuttings in the same gray rocks where 
 the dip is S. 50° W. mag. < 50° , and a little further, S. 20° W. mag. 
 < 80°. These gray rocks continue along the railroad about 1,500 feet 
 further, and are supposed to be about the middle of the Etcheminian. 
 Passing up from Young's house across the railway to the road, one 
 meets with ledges of gray, cream-weathering argillites which belong 
 to the upper division of the Etcheminian. They extend from the 
 school-house along the highway toward Barachois, and southwardly 
 along the west side of the valley of Young's brook. 
 
 Along the shore of Long island passage at the foot of this ridge of 
 argillites on the western side are dark-gray slates and gray flags of the 
 St. John terrane. 
 
 A section in a south-east direction across the Cambrian basin from 
 SectioE. Young's point, on St. Andrews channel, for half a mile, to the syenite 
 
 of the Boisdale hills would give the following succession : 
 500 feet red and gray slates and sandstones = Lower Etcheminian. 
 
 The base of the terrane is concealed by the water of St. Andrews 
 
 channel. 
 1,500 feet fine gray and some coarser argillites. Anticlinal in Upper 
 
 Etcheminian. 
 300 feet in valley of Young's brook = Part of St. John group. 
 300 feet unexplored to border of syenite as given by Mr. Fletcher. 
 
 Returning to Young's house and the shore of St. Andrews channel 
 in front of it, the red slates which were seen east of Young's brook 
 are here well exposed in a low cliff along the shore. They are more 
 fossiliferous here, and when not too strongly cleaved show well-preserved 
 examples of Lingulella, especially L. Selwyni. 
 
 Fossils were first observed by JSlr. Fletcher, and subsequently by 
 Fossils Messrs. Weston and Robert of the Survey staff, who were sent here to 
 
 Mr.* Fletcher, collect. It is not quite certain to me that they collected from Young 
 point as their collections are marked McAfee point, and their speci- 
 mens are larger than those I found, but the similarity of the fossils 
 show they were from the same division of the Etcheminian. The 
 collections made-here by Messrs. Weston and Robert were some years 
 ago placed in the writer's hands for study, and they appeared to 
 
19 
 
 agree best with those o£ Lower Ordovician age, and so were considered 
 to be of that system. The dips and strikes marked by Mr. Fletcher 
 on his map appeared to agree with this view, as they showed a series 
 parallel to the shore of St. Andrews channel, whereas the Cambrian 
 beds in Long island passage exhibited a dififerent strike. A personal 
 visit to the locality has now convinced me that these beds, in place of 
 being at the summit of the Cambrian, are towards its base, and are in 
 fact of the lower division of the Etcheminian. 
 
 The fossiliferous series extends in a low cliff along the shore of St. 
 Andrews channel from Young point nearly to the mouth of Young 
 brook, the cliff falling to the level of the beach as it approaches that 
 stream. As the section runs nearly on the strike of the beds, only a 
 small part of the lower division is exposed. The highest beds seen 
 come from beneath a mass of Lower Carboniferous limestone on Young Section of 
 
 liOwer 
 
 point, and progressively show lower beds for a distance of 150 feet along Etcheminian 
 the shore. There is no lack of fossils, but the cleavage being transverse poiQ°""^ 
 to the bedding those in the slates are greatly obscured, but in the sandy 
 beds they are less distorted. It is in the lower beds, including a bed 
 of grit 2^ to 5 feet thick, that the greatest variety of fossils is found. 
 
 Vertical section at Toung point. Scale Jfi feet to cm, inch. 
 Lower Carboniferous limestone. 
 
 \aJC' 
 
 10 
 
 (Ajt 
 
 25- 
 SuAr 
 
 r?^affc 
 
 15 
 
 Sandy shales and sandstones, chiefly gray sandstone and purplish- 
 gray slate, the former predominating. The sandstones have pebbles 
 and nodules coated with hematite, vertical worm burrows, (Areni- 
 colites and Monoeraterion), and shells of Lingulella are scattered 
 over the layers. 
 
 Purplish-gray sandy shale. 
 
 Sandy layer with Lingulella, &c. 
 
 Purplish-red shale with Lingulella, &c., and a cream-coloured layer 
 
 of falsi te sand. 
 
 Red sandy slate, vidth scattered Lingulella, sharply folded against 
 the bed of grit. 
 
 Grit, gray above, purplish-red below. Pebbles of slate, felsite 
 quartzite and black silicious slate. Lingulella common. 
 
 Purplish-red shale, colour deepened in the seams and cleavage planes 
 by hematite. Lingulella common. 
 
 2J— C. R. 
 
20 
 
 Etcheiiiinian 
 section on 
 Steele brook. 
 
 Plateau of 
 Cambrian 
 rocks in 
 Indian brook 
 valley. 
 
 No lower beds than these could be determined. 
 
 The 25 feet bed of slate comes down to the waterline about 150 feet 
 east of Young point and then borders the shore for some distance. 
 The dip then changes and the lower slates and grit reappear and dip 
 S. 70° W. mag. < 70°. Further on the dip is S. 30° W. mag. < 30°. 
 Then after a space where there are no exposures, one comes to the gray 
 flaggy beds above mentioned which appear also in the railway cuttings. 
 Here the dip is S. 50° E. mag. < 70°. 
 
 The fossils from this shore are described in the Palseontological sec- 
 tion of t&is report. 
 
 Exposures of what appear to be Etcheminian sediment are des- 
 cribed by Mr. Fletcher as occurring on Steele brook, a small aflSiuent 
 of McLeod brook near its source. They are described at page 429 of 
 the Report of Progress for 1876-7. Nos. 1, 4 and 7 have the characters 
 of the strata of this part of the Cambrian system. On the supposition 
 that the limestone and felsite are introduced into the Etcheminian 
 rooks by faults, this reference of the numbers above quoted would be 
 admissible. In connection with his description of the rocks of No. 3, 
 of this section, Mr. Fletcher suggests the existence of a fault. This 
 section would be unintelligible otherwise, as the natural position of 
 the sandstones, if Etcheminian, is 1,000 feet or more below the black 
 and gray shales of the bottom of the valley. These sandstones then 
 appear to have been raised that distance above the St. John terrane, 
 which fills the bottom of the valley. 
 
 The basin of Cambrian rooks in the valley of Indian brook is just 
 such a narrow trough as that of the Barachois basin, but the structure 
 of the beds is entirely different. In tfce Barachois basin we trace an 
 ascending series from the base of the Etcheminian at George river 
 station to the head of McLeod brook, but on Indian brook the Cam- 
 brian rocks show an upward succession from the basal beds on the 
 north-west side of the valley to the higher Cambrian beds on the 
 south-east side. In this narrow valley the three terranes of the Cam- 
 brian stand on edge or as a series of vertical beds which form a plateau 
 on the western side of the valley, while Indian brook runs in a deep 
 and narrow trench along the eastern side. The valley is closed in on 
 each side by higher plateaux of pre-Cambrian rocks consisting of cry- 
 stalline limestones, felsites, various schists, and some beds of black 
 flinty slates, the whole of the pre-Cambrian being cut, broken up and 
 altered by great masses of intrusive syenite, also of pre-Cambrian age. 
 
 Owing to the elevation of the Cambrian plateau in this valley and 
 the short courses of the brooks after they descend from the pre-Cam- 
 
•21 
 
 ^=.r?. — »*-i?^4iBaa? shale. 
 
 '• ' ^''^^ i' /" I*' ' ^\^^^ 
 '■-i '*\\[V'i/jfy Linfnilepis prepwa. 
 
 nil li 
 
 5 5 OiaUes lens 
 
 
 GORGE OF DUGALD BROOK 
 
 Sfunrin^ the Ftzfiermnian. tememe 
 Sca.le2G£feei:-6i?J zrtc^ 
 
brian upland, most of them have cut deep gorges on their way to the 
 main stream, and some good sections of the Cambrian rocks have been 
 exposed. The best of these for the Coldbrook and fitcheminian 
 terranes is that of Dugald brook. (See preceding page.) 
 
 Section on The Etcheminian terrane is exposed in the gorge below the falls at 
 
 Dugald brook in a series of vertical beds from the base to the summit 
 of the terrane. The measures are cut at right angles to their course 
 which is N. 60° (mag.) and present the following upward succession. 
 
 Division 1. In all 122 feet. 
 Assise a consists of 
 
 1 5 feet dark purple amygdaloid and bright red slate — Fossils. 
 10 feet dark purplish-gray trap and ash-rock. 
 18 feet soft purplish-red shale. 
 Assise b consists of 
 
 18 feet dark purplish-gray finely crystalline trap. 
 10 feet measures concealed (shales ') 
 6 feet gray quarbzites. Fossils in sand and clay seams at the top. 
 Assise c consists of 
 
 21 feet dark gray shale. Fossils at the middle of the assise, in 
 soft layers. 
 
 Assise d consists of 
 
 21 feet compact dark gray sandy shale. 
 Assise e consists of 
 
 3 feet gray shale with seams of greenish-gray sand and lavender 
 gray clay. Each of these assises is fossiliferous. 
 
 Notes on ihejossils of Division 1.- 
 
 Those of Assise a are found in the bright red shale. They are very 
 much corroded and therefore obscure, a Hyolithes, a Lingulella and 
 worm-burrows are recognisable. 
 
 Fossils of As.siSE b. — The matrices of the fossils are seams of greenish gray- 
 
 Division 1. weathering sand, in layers of lavender gray, rusty-weathering fine 
 shale. The grains of the sandy layers are mostly of pellucid and of 
 green quartz. Some grains are of a bright copper-green colour. There 
 are numerous minute fragments of red feldspar (and of red felsite?) 
 not kaolinized. There is a pale green (magnesian?) deposit in places 
 among the .sand grains. The sand is mixed with numerous fragments 
 of the shells of Brachiopods and a few Ostracods. 
 
23 
 
 Fossils — 
 
 Acrothyra signata ventrals 7 dorsals 4 
 
 Leptobolus 1 " 1 " 1 
 
 Obolus triparilis " 3 " 4 
 
 Lingulella longovalis " 2 " 1 
 
 Lingulepis Gregwa? (mould) 1 " 
 
 Bradorona spectator-acuta right v. 2 left v. 
 
 B. observator-lsevis " 2 "2 
 
 Bradoria vigilans-obesa, &o " 1 "1 
 
 Assise c. — The fossiliferous band in this assise is a fine gray to Assise c 
 
 lavender gray shale, weathering pale brown in cracks. 
 
 Fossils — 
 
 Acrothyra signata-sera ventral 59 dorsals 53 
 
 its 
 
 fossils. 
 
 tarda . 
 
 Obolus triparilis. " 
 
 Lingulella cf tumida. " 
 
 L. longovalis " 1 
 
 Lingulepis Gregwa... . ; " 
 
 Hyolithes, wide apertural angle tube 2 
 
 Orthotheca sp " 2 
 
 Bradorona perspicator-maxima . right v. 1 left v. 
 
 B. spectator " 1 " , 
 
 Bradoria ornata " 1 " 
 
 B. vigilans, mut " 1 " 1 
 
 Crustacean, part of carapace .... 1 
 
 Assise d. — The rock is a comparatively uniform mass of gray to Assise d, 
 brownish-gray shale, of uniform texture, somewhat charged with fine ' * °^^ ^' 
 sand which consists largely of feldspathic particles. There are grains 
 of a soft grass-green mineral and of kaolinized feldspar. Lingulepis 
 Gregwa is scattered through a considerable thickness of this assise. 
 
 Acrothyra signata-tarda ventral 24 dorsal 27 
 
 Acrotreta papillata " 2 " 1 
 
 Lingulepis Gregwa " 42 " 38 
 
 L. — '■ var " 5 " 5 
 
 Orthotheca sp tube 2 
 
 Bradorona spectator right v. left v. 2 
 
 B. acuta ". . " 2 " 
 
Aasise e, 
 its fossils. 
 
 Assises of 
 Division 2. 
 
 24 
 
 Assise e. — The fossils of this assise are contained in greenish-gray- 
 sand, alternating with layers of lavender-gray clay. The sand is 
 mostly pellucid quartz, and there are diflFused pale green particles and 
 films, which may be glauconite or some magnesian silicate. There are 
 also black grains and a few lumps of calcium phosphate. Some of the 
 fossils are fragmentary. 
 
 Fossils — 
 
 Obolus discus young 2, veptral 1 dorsal 4 
 
 Lingulella longovalis " 14 " 8 
 
 L. cftumida " 2 " 4 
 
 Lingulepis Gregwa, var " '2 " 1 
 
 Leptobolus sp " 1 " 2 
 
 Orthotheca sp part of tube 1 
 
 Hyolithes, sp " 1 
 
 Bradorona spectator-spinosa , , right v. 1, left v. 1 
 
 Indiana ovalis " 1, " 1 
 
 Division 2. 151 feet. 
 Assise a consists of 
 
 3 feet of gray fine-grained felsite-conglomerate and grit. 
 33 " dark purplish gray feldspathic sandstone with some 
 
 slate conglomerate. 
 37 " • same rock with beds of gray quartzite about the 
 middle. The fossils are in the lower half of the 
 assise. 
 
 Assise b consists of 
 
 57 feet dark purplish-gray feldspathic sandstone. Fossils are in 
 the lower part of the assise. 
 Assise c consists of 21 feet of similar sandstones, with a bed of gray 
 
 conglomerate holding pebbles of purplish-gray (and a few of red) 
 
 felsite, with some of black flinty slate. Fossils at the top of the 
 
 assise. 
 
 Notes on the fossils of Division 2. 
 
 AssiSK a. — Fossils are rare and poorly preserved in these coarse 
 beds. Only a Lingulella was seen. 
 
 Assise h. — In the sandstones of this assise are abundant grains of 
 non-kaolinized red feldspar. The rock is strongly cemented and has 
 some small calcite veins : the cement is partly calcareous, but there is 
 enough iron to give the rock a rusty-brown colour when weathered. 
 
25 
 
 There are pieces of black siliceous slate and small pebbles of quartz. 
 The Brachiopods of this band are not much corroded and have their 
 natural contours. 
 
 Fossils — 
 
 Acrothyra signata-tarda ventral 1 dorsal Fossils of 
 
 Lingulepis longinervis " 9 " 9 
 
 Orthotheca. tube 1 
 
 Bradorona perspicator-magna . . . right v. 2 left v. 
 
 Assise c. — Fine grained greenish gray sandstone with purple cloud- 
 ings carry the fossils. 
 
 Fossils — 
 
 Acrothyra signata-orta ventrals 3, dorsals 2 
 
 Bradorona observator-l«vis . . . right v. 2 left v. 
 
 Division 3. 234 feet. Assises of 
 
 Division 3. 
 Assise a consists of 
 
 4 feet gray shale with abundant scales of hydro-mica. 
 
 50 " dark gray feldspathic sandstones, having seams of gray 
 
 grit with felsite debris. 
 
 Assise b consists of 
 
 25 feet fine gray shale. 
 Assise c consists of 
 
 25 feet gray argillaceous sandstone. 
 
 Assise d consists of 
 
 30 feet dark gray, and some purplish-gray shale. 
 
 Assise e consists of 
 
 18 feet dark gray shale, the beds alternately harder and softer. 
 
 Assise y consists of 
 
 40 feet dark gray somewhat siliceous flaggy shales, with pale gray 
 
 seams at intervals. 
 32 " dark gray, rather coarse shales. 
 10 " siliceous gray shale. 
 The fossils are mostly from the middle of this assise. 
 Notes on thejossils, &c., of Division S. 
 
 Assise a. — The rock containing the fossils in this assise is a lavender- Fosails of 
 gray to pure gray shale, weathering yellowish in the cracks, and 
 
26 
 
 Fossils of 
 Assise 6. 
 
 Of Assise c. 
 
 Of Assise d. 
 
 probably containing some carbonate of iron ; there is some fine felsite 
 sand, and minute spangles of white mica. 
 
 Acrothyra proavia-prima. 
 
 Acrothele aba via 
 
 Obolus Bretonensis ...... 
 
 Lingulella sp 
 
 Leptobolus sp 
 
 . ventrals 7, dorsals 10 
 
 "4 "1 
 
 . "1 "0 
 
 "1 "0 
 
 " " 1 
 
 Assise h. — Purplish-gray shale with much diffused hematite, the 
 rock giving a purplish-gray streak ; quite minute spangles of white 
 mica are present. The fossils of this layer are much corroded, and do 
 not show good surfaces. 
 
 Fossils- 
 
 Acrothele aba via ventrals 12 dorsals 21 
 
 A avia ? " 1 " ' 1 
 
 Obolus lens young 2, " 4 " 3 
 
 Leptobolus atavus (long). , . " 5 " 7 
 
 Trilobite, 
 
 sp.. 
 
 . a pleura with a deep furrow 1 
 
 Assise c. — The rock in which these fossils are embedded is a purplish- 
 gray shale, with considerable diffused hematite and small spangles of 
 silvery mica. The fossils are badly corroded, and the Leptoboli in 
 consequence of the thinness of their shells are much distorted. 
 
 Fossils — 
 
 Acrotreta, sp ventral 0, dorsal 1 
 
 Actrothele abavia (on slab) .... 'i 4, dorsal 4 
 
 Leptobolus collicia " 13 15 
 
 Lingulella, sp " 1 
 
 Assise d. — The rock containing the fossils is a gray and purplish- 
 gray shale, with very minute spangles of gray mica. Obolus Breton- 
 ensis is near the bottom of this assise. 
 
 Fossils- 
 
 Acrothele avia ventral 5, dorsal 7 
 
 Obolus Bretonensis.. . . young, 1, " 6, " 4 
 
 Leptobolus atavus " 32, " 33 
 
 Bradorona spectator-sequat right v. 1, left v. 2. 
 
scarce. 
 
 27 
 
 Assise e. — Gray shale with flaggy layers, the lamination due to Of Assise e. 
 seams covered with shells, alternating with others where the shells are 
 The rock has spangles of silvery gray mica. 
 
 Acrothyra proavia ventrals 160, dorsals 160 
 
 A — crassa " 1 " 
 
 Acrothele avia " 9 " 10 
 
 A abavia " 5 " 
 
 Obolus lens. " 17 " 16 
 
 O lens-Iongus " 3 " 1 
 
 Leptobolus ooUicia " 18 " 26 
 
 L atavus " 69 " 63 
 
 Lingulella, sp " " 1 
 
 Indiana ovalis right v. 1 left v. 1 
 
 Bradorona scrutator .... " 3 " 1 
 
 B observator-ligata. " 2 " 2 
 
 Bradoria vigilans. ....... " 6 " 2 
 
 B -— rugulosa " 5 " 3 
 
 Schmidtella ? pervetus. . . " 2 " 1 
 
 S ? acuta " 3 " 3 
 
 Assise y. — The rock containing the fossils is a gray shale, more 
 sandy than that of assise e. Some of the layers have a purplish tinge, 
 and the spangles of silvery mica that occur are larger than those of 
 the assise below. The highest band of these shales is quite silicious. 
 
 Fossils— 
 
 Acrothyra proa via- prima ? ventral 1, dorsal 
 
 Of Assise /. 
 
 A crassa?. 
 
 Acrothele proles . . . 
 L coUicia. 
 
 Leptobolus coUicia collis . 
 L atavus , 
 
 Bradorona perspicator-major. 
 B scrutator 
 
 " 1 
 
 " 
 
 '■■ 23 
 
 " 12 
 
 " 6 
 
 " 2 
 
 " 21 
 
 " 16 
 
 " 
 
 " 1 
 
 right V. 1 
 
 left V 1 
 
 
 
 " 1 
 
 t 
 
 2 
 
 Solenopleura (?) Bretonensis part 
 
 At the top of this assise the Etcheminian terrane is overlain by a 
 body of felsite conglomerate, which rises in a wall-like mass one hun. 
 dred feet or more in height, and turns the course of the stream west- 
 
 ^^^"^A- _ Conglomerate 
 
 Further down stream it is seen that this conglomerate, which is re- a* Jte base 
 
 ,., o-i... oibt. J onn 
 
 garded as the base of the St. John terrane, has a thickness ot thirty group. 
 
28 
 
 feet, and contains partly rounded pebbles of felsite in a felsitic paste. 
 It is followed by dark gray feldspathic amydgaloid and dark gray 
 porphyritic greenstone. 
 
 About half a mile north-east of Dugald brc)ok a traverse was made 
 across the Cambrian plateau. Except some purplish-gray sandstones 
 at the foot of the syenite hill, there are no exposures for 925 feet. 
 There is then a rising slope of 150 feet showing some exposures of the 
 Upper Etcheminian shales. Then ninety feet to a ridge of felsite- 
 breccia with seams of gray shale ; this seems to be the equivalent of the 
 basal conglomerate of the St. John terrane seen in the gorge at Dugald 
 brook. Following this, in a space of seventy-five feet, there is a ridge 
 of dark gray ash-grit with a paste of a partly gray to dark gray felsitic 
 sand, partly a conglomerate with felsite pebbles, one inch across. The 
 dip here is S. 20° E. mag, < 70°. This also is a part of the St. John 
 terrane. 
 
 In this section the Coldbrook and Etcheminian terranes occupy a 
 a quarter more' space than they do at Dugald brook, where, however, 
 they are vertical. 
 
 Section on The small brook at the boundary of the Indian reservation of 
 
 Boundary . . i m n 
 
 brook. Escasonie on its eastern side, affords a somewhat interrupted section 
 
 that throws additional light on the relation of the Etcheminian to the 
 
 St. John terrane. As at the former brook, the base of the Cambrian 
 
 rests against pre-Cambrian schists and intrusive rocks. The lowest 
 
 bed noticed was a reddish quartzite, not measured, but having a 
 
 thickness of about thirty feet. 
 
 30 feet reddish-gray quartzites. 
 
 30 " soft red sandstone, full of quartz veins and frag- 
 ments of feldspar. 
 
 Assises 35 " dark purplish-gray felsite-conglomerate. It forms 
 a ridge broken through by the brook 
 
 Assise c 25 " lower part, purplish-gray felsite shale. Ostra- 
 cods and small Brachiopods occur, but they 
 are rare. 
 
 20 " purplish-gray sandy shale. Fossils abundant. 
 25 " dark gray shale, Lingulepis Gregwa common. 
 Assise e 25 " no exposures to the bridge at the road. 
 
 190 Division 1 of the Etcheminian. 
 
 Assise a 
 
 Assise d 
 
29 
 
 150 feet. No exposures on the brook, but a sma 1 ri bu- 
 tary coming in from the east, on the line of 
 strike has purplish-red sandstones of Division 2. 
 
 100 feet. No exposures except at the top where there are 
 dark purplish-gray sandstones with veins and 
 seams of hematite. 
 
 250 Division 2 of the Etcheminian. 
 
 15 feet gray argillite or shale. 
 
 30 " measures concealed. 
 
 15 " felsite conglomerate, with fragments of black 
 
 silicious slate. 
 50 " gray sandstones, flags and slates. 
 
 110 Division 3 of the Etcheminian. 
 
 This section shows a thickening of the two lower divisions of the 
 Etcheminian, but the upper division is greatly reduced in bulk, per- 
 haps by erosion prior to the deposition of the St. John terrane. The 
 beds of Division 1 are correlated with those of Dugald brook, partly 
 by lithologioal resemblances, and partly by their fossil contents. Col- Fossils of 
 lections were made from Assise d, of Division 1 , and the following Diligfon i on 
 
 fossils determined : — Boundary 
 
 brook. 
 
 Fossils : 
 
 Acrotreta papillata ventrals 25, dorsals 24 
 
 Obolus sp " 2 " 
 
 Leptobolus cf atavus " 5 " 3 
 
 L cf. collicia " 3 " 1 
 
 Lingulepis Gregsva. . .yng 8, ventrals 40, dorsals 44 
 
 L sp " 5 " 3 
 
 Orthotheca sp., broken tube 2 
 
 Bradorona perspicator, right v. 2, left v. 2 
 
 Bradorona spectator . . " 5 " 9 
 
 B observator. « 4 « 8 
 
 B benepuncta, right v. 3, left v. 2 
 
 Bradoria vigilans, mut " 1 " 
 
 Escasona rutellum-prima. . . " " 1 
 
 Schmidtella (1) pervetus-concinna " " 1 
 
Supposed 
 ero3ion of tlie 
 Upper 
 Etoheminian. 
 
 Acadian divi- 
 sion of the St. 
 John group. 
 
 30 
 
 It is assumed above thafc the upper division of the Etoheminian ends 
 at the great conglomerate named below. If, however, the lower con- 
 glomerate, 15 feet, (named above) be taken as the base of the St. John 
 group (there are three conglomerates in it on McMullin brook), there 
 are only 45 feet of measures of the Upper Etoheminian at Boundary 
 brook, whereas on Dugald brook there are 230 feet. At Vincent Mc- 
 Phee's farm, half a mile northeast of Boundary brook, the Upper 
 Etoheminian is 120 feet thick. The nature of the Upper Etoheminian 
 sediments is such as to make it improbable that the great differences 
 in the bulk of this member can be due to variation in its original 
 thickness. It is more likely to be due to erosion of this division before 
 the deposition of the St. John group, or to faults that have cut out a 
 great part of this member of the series. 
 
 70 feet felsite conglomerate, with pebbles of felsite, &c. 
 
 20 feet gray ochrous-weathering clay slate. Impressions of sea- 
 weeds in lower part. 
 
 20 feet hard compact gray slate. 
 
 20 feet measures concealed. 
 
 20 feet light buff felsite conglomerate with ochrous spots. 
 
 40 feet measures concealed. 
 
 40 feet gray flags and sandy slates, followed by gray flags and 
 quartzites. 
 
 The Acadian division of the St. John group would come into 
 230 this part of the section. 
 
 Johannian 
 division of 
 this group. 
 
 50 feet gray felsite-oonglomerate. 
 40 feet gray slate and quartzite. 
 60 feet measures concealed. 
 30 feet channel of Indian brook. 
 
 180 Part of the Johannian division. 
 
 This last portion of this section may be assigned to the Johannian 
 division of the St. John group, but it is obviously only a small portion 
 of this division. Possibly the eighty feet (40-1-40) here assigned to 
 the Acadian division should be transferred to the Johannian. 
 
31 
 
 Westward of Boundary brook, a large stream called Gregwa brook, Section of 
 runs across the Indian reservation. In its lower course it is cut down Qj™'^,"™ °° 
 nearly to the level of Indian brook, of which it is a tributary, and so brook. 
 does not give continuous exposures. In going up the stream the first 
 ledges met with are the felsite-conglomerates of the Acadian division 
 of the St. John group. The intervening flags and slates, being softer, 
 are not exposed. A fine-grainnd slate appears further up stream in 
 which no fossils were found, and beyond this, ,in the banks and 
 channel, gray shales occur. These shales contain Obolus Bretonensis Upper 
 and an Acrothele and therefore are assigned to Assise d of the Etcheminian. 
 Upper Etcheminian. The valley here is narrowed by abrupt hills, 
 which consist of purplish-gray feldspathic sandstones, rich in iron, 
 as they contain fahlbands of hematite. These sandstones belong to 
 Division 2 of the Etcheminian terrane. 
 
 Above this, on the east branch of this brook, are some exposures of Lower divi- 
 gray rusty-weathering shales, holding the place of Assises c, d and e of same and the 
 the lower division of the Etcheminian terrane. Further up the brook ^^^ne "'^ 
 are purplish-red schist and sandstone that hold the place of Assises a 
 and h of this division. They dip N. 30° W. mag. < 70. Here the 
 section passes to the gray amygdaloids and feldspathic rocks of the 
 Coldbrook terrane, over which this branch falls in cascades to the 
 valley below. Above the falls these effusives continue for a short 
 space and show purplish-red felsite rock, porphyritic and amygdaloi- 
 dal. There is no great body of these effusives. On the main or west 
 branch of Gregwa brook a similar succession is found. Here the 
 lowest Etcheminian beds seen correspond to Assises a and h of Divi- 
 sion 1, and consist of dark-red, crumbling calciferous conglomerate ; 
 this passes into a dark-red sandstone, and is succeeded by red, and 
 then gray quartzites in massive beds. 
 
 An examination was made of the Etcheminian and St. John terranes Section of 
 at Gillis brook, a branch of Indian brook, to near its source, for com- Giffis' brook 
 parison with the section of Dugald brook. This section is about two ^a^^ff^^ 
 and a half miles north-east of Dugald brook. There are two branches brook valley. 
 of this brook, of which the western comes down from a granite hill to 
 the north of Gillis house, and the eastern comes from lower land to 
 the eastward, but traverses the same terranes as the western branch. 
 
 Where the western branch comes off the granite hill, a thin body of 
 amygdaloidal ash- rock is all there is to represent the Coldbrook terrane. 
 Resting on this is a narrow ridge of pink quartzites, upon which lie 
 some beds of purplish-red sandstones. South of these there is a space 
 where the measures are concealed, and following this the felsite breccia- 
 
32 
 
 conglomerate that marks the base of the St. John terrane. The space 
 between the granite and this conglomerate, measured by my assistant, 
 was two hundred feet. The indications are that the whole three 
 divisions of the Etoheminian are represented in this space as well as 
 the Coldbrook terrane, and it appears to be a case of scant deposition, 
 such as marks some of the valleys holding Cambrian deposits in 
 New Brunswick. 
 
 The Etoheminian measures, which are out of sight in this section, 
 appear on the eastern branch of Gillis brook where they occupy the 
 bed of the stream with the breccia-conglomerate (of the St. John ter- 
 rane) on the south and the purplish-red sandstones and pink quartzites 
 to the north. The breccia-conglomerate here is full of fragments of 
 felsite, and of the red granite which appears in the hill to the north, 
 and there are a few fragments of black silicious slate, all of which are 
 found as rock masses, either in the Coldbrook terrane, or in the ad- 
 joining pre-Cambrian complex. 
 
 Fossils at On the east branch of Gillis brook, where the beds of Division 3 are 
 
 Orillis brook, i i • i i i 
 
 Indian brook, exposed beside the breccia-conglomerate, they contain various fossils, as 
 
 Acroihyra proaviacrassa, Acrothele proles, A. avia-puteis, Leptoholus 
 
 coUicia, Leptoholus collis, Bradorona scrutator, a trilobite, Soleno- 
 
 pleura (?), &c. Between the ridge of breccia-conglomerate behind 
 
 Gillis house and the deep valley of Indian brook, the land descends 
 
 rapidly, and there are a few exposures of the gray flags and slates of 
 
 the Johannian division of the St. John terrane ; the space to Indian 
 
 brook is about 2000 feet. 
 
 THICKNESS OF THE ETOHEMINIAN IN THE VALLEY OF THE MIEA EIVEE. 
 
 Basal In this valley I could not find the breccia-conglomerate, which on 
 
 of St. John East bay so distinctly marks the upper limit of the Etcheminian ter- 
 uilh'^ w^™' rane. The top of this group and the base of the St. John group in the 
 valky. Mira valley each consists of soft and fine sediments, and from the ero- 
 
 sion of these beds the contact between the two terranesis seldom seen. 
 Their colour and relation to the overlying mass of fiags and quartzites 
 of the Johannian division of the St. John group will often serve to 
 distinguish them. The slates of the Acadian division of the St. John 
 group in this valley are dark gray (often purplish-gray weathering) ; 
 those of the upper division of the Etoheminian are compact pale gray 
 (often greenish-gray weathering) ; there are also purplish-red slates in 
 this division, while only pure gray, or faintly purplish beds are known 
 in the St. John group. 
 
33 
 
 A section was examined some years ago by Mr. Hugh Fletcher, Section on 
 who found in the gorge at the old mill at McCodrum brook the fol- brook, 
 lowing measures : — 
 
 Feet. 
 
 1. Reddish, fine, coherent micaceous sandstone 16 
 
 2. White quartzite, or grit, in which the grains 
 
 are scarcely distinguishable. It passes 
 into white quartzose conglomerate 10 
 
 3. Purple, pebbly, close-grained quartzose grit, 
 
 passing, lower down the brook, into red- 
 dish conglomerate with pebbles as large 
 as hazel nuts. Dip. N. 76° E. < 30° 1 
 
 4r. Greenish-gray, soft somewhat soapy and 
 
 flaggy argillite. Dip.N. 53° E. < 29°. . . 59 
 
 5. Greenish, nearly compact micaceous sand- 
 stone, slaty or in even flaggy beds. It 
 forms curious gorges and falls, being cut 
 on the strike for a great distance, so that 
 the angle of dip is the slope of the right 
 bank of the brook. Dip. JST. 50° E. < 33°. 540 
 
 626 
 
 In quoting this section I have reversed Mr. Fletcher's numbers. 
 His record of dips on the lower part of the brook south of this section 
 shows that the Etcheminian here is mantling around the felsite hill, 
 ' McCodrum mountain,' and the lower part of the lower division of 
 the Etcheminian is thin. Nos. 1, 2 and 3 correspond to the assises 
 a and' 6 of the lower division, and No. 4 to the assises c, d and e. 
 Lingulepis Gregwa and other brachiopods, not well preserved, are 
 found in the slates on McCodrum brook. No. 5 is chiefly the' middle 
 division of the Etcheminian, of a grayer colour than in Indian Brook 
 valley. 
 
 The beds at the contact of Nos. 3 and 4 have seams of red and pale 
 yellow ochre. They are finer than the corresponding shales on Dugald 
 Brook. 
 
 On the west side of the Mira valley we found no exposures that 
 would exhibit a continuous section of the Etcheminian terrane, nor 
 on the east side were there any such ; but on this side, exposures of 
 ledges along the roads and streams and the surface soil show that the 
 group is well developed. 
 
 3— c. R. 
 
34 
 
 5^\^ DebrCs of purplish redslatp 
 Slocks oFof~eF aroMies. 
 
 Debris oforey ccraMcte. 
 Yi^Uow an^ Ar'/TjmijA soiZ^ with 
 
 as farcer ^fzcse ben^s. 
 
 Blocks of purplish grey-oieartzite. 
 Slocks anei. siozics of 
 purplis/i- j"!^ sartiistOTie, 
 
 Pu-rplish. ai'ey- jamCsO/ne. 
 
 purplish reeZ c/e^ sl^Us. 
 Dtp S.SO'S ^Meyr. Mi?r'^)<dO' 
 
 PurpUjf'Gleispat/uc sctn^tDne.. 
 Sleeks ofsayn^ 
 
 Puryjlieh. red c<>rytlorrvcr-ctte 
 
 Dip y.so'TrfMa^. nrerrj< SO'^sa' 
 
 ETCHEMIIMIAN TERRANE, W. BENGAL ROAD 
 Scale woafeet -tv one i/zrJt- 
 
35 
 
 (See map opposite.) Traverse on 
 
 On the West Bengal road the contact of this terrane with the road. 
 eflFusive rocks of the Coldbrook is seen a short distance north of 
 A. McDonald's, where a heavy conglomerate with pebbles of quartz and 
 felsite crosses the road in vertical beds. For about half way to the 
 corner of this road and the Trout brook road at Johnson's, purplish- 
 red sandstone in blocks or ledges indicates the presence of the Ijower 
 Etcheminiau (Divisions 1 and 2). A quartzite ledge marks the passage 
 to the Upper Division. The thickness of the Lower Etcheminian 
 here is estimated at 1,300 feet. In the two-thirds of this there is 
 much hard purplish-gray feldspathic sandstone and slate, weathering 
 lavender gray. ^^^^ 
 
 For another half mile the road runs diagonally across a low ridge, Etcheminian. 
 where, from the soil exposed and the ledges and blocks visible, it may 
 be inferred that the upper division of the Etcheminian terrane is 
 present. From the known strike of the argillites visible here, it is 
 estimated that there are 1,100 feet in width of measures of the pale 
 gray argillites. There is also north of the road, at Johnson's, 600 
 feet in width of a swale filled with debris of purplish-red slates, which 
 appears to be of the same terrane. Such stj'ata were not seen in the 
 Cambrian basins of East bay and St. Andrews channel to the north- 
 west. With this addition there are 1,700 feet of Upper Etcheminian 
 rocks on this side of the Mira valley at West Bengal road. Thickness in 
 
 A comparison will show, if the thickness has not been increased by compared, 
 faults, how much thicker the Etcheminian is here than in the Indian 
 brook valley. 
 
 Dugald Brook. Bengal Road. 
 
 Feet. Feet. 
 
 Division 1 120 .... 400 
 
 2 150 .... 900 
 
 " 3 230 .... 1,100 
 
 Additional measures .... 600 
 
 500 3,000 
 
 THICKNESS ON THE EAST BRANCH OF THE BENGAL ROAD. 
 
 Another traverse of the Etcheminian was made on the north part 
 of the Bengal road and its eastern branch leading to Bengal settlement. 
 Here to the east of Mclnnis lake, the soil and some ledges show a 
 width of 1,200 feet occupied by the measures of the lower division, or 
 for a distance along the road of 2,000 feet. For an equal distance 
 ^—c. E. 
 
fiaradoxuiei 
 
 Red. and ^r^ slaie eieAris 
 
 Seel cla^ slatB. MimctxfossUs. 
 ^rejeayilUtes. Dip. N.so'WfMay.) < SO? 
 
 J)ipW.Z0-W:fMe^.)<90f 
 Gxvj^ euyiUite de6ris. 
 
 ^i^ifff" soiZ j stones arej- araillitB. 
 BittariaZ hnolZs 
 
 JDiUariceZy^lett:. 
 
 Mitffseil. St9neo/'/>ury>le. Sc^reysUtte. 
 
 Tarm. rocul. 
 
 Purplieh red soU vritfi. mi44Ji 
 Ted- shzts dehrts. 
 
 PurpUsft, red soil with. mU'Ch. red 
 slatB debris alotw Tterc. 
 
 M "^ T &r\A Cjnrnprs/^^'^^ jnnrplish- reeLash sla^ St sandstc^rtiL 
 
 ETCHEMIMIAN TERRANE , E. BENGAL ROAD. 
 Scexleiooq/eet «5? Ofie tn£^ 
 
37 
 
 along the road and at right angles to the strike, no ledges are exposed 
 where the road crosses the valley in which Mclnnis lake lies. This 
 valley is filled with modified drift. 
 
 On the ridge north of this valley, however, where the West Bengal 
 ro^d branches ofi", there is a breadth of 1,200 feet of nearly vertical 
 argillites of the Upper Etcheminian ; and north of these, in a swale, 
 800 feet of red and purplish-gray argillite, of the supposed additional 
 member at the top of the Etcheminian. Comparing this section with Traverse on 
 the one on the west branch of the Bengal road the following propor- j.yad. *°^* 
 tions appear : — • 
 
 West Bengal E,oad. East Bengal Road. 
 
 Feet. Feet. 
 
 Division 1 400 1,200 
 
 2 900 2,000 
 
 3.. 1,100 .. . 1,200 
 
 Upper red argillites 600 . . , , 800 
 
 3,000 5,200 
 
 Above the upper red slates a mass of fine dark gray (purplish-gray 
 weathering) clay slates is exposed for a width of 800 feet. As these 
 contain species of the Paradoxides fauna they are to be assigned to 
 the Acadian division of I he St. John group. 
 
 THICKNESS OF THE ETCHEMINIAN ON THE BOSTON ROAD. 
 
 (See map on opposite page.) 
 On this road the Cambrian rocks are mostly concealed by glacial 
 debris or by woodlands. Coming down off the ridge of Coldbrook 
 effusives in the Bengal settlement, at a point about two miles and a 
 half north-east of the preceding section, the presence of basal beds of 
 the Etcheminian is recognizable in a red soil, full of fragments of ^ ^^ 
 purplish red sandstone. This soil continues to the stream draining Etcheminian 
 the valley in which Mclnnis lake lies, and up the slope op the north road."^*"" 
 side of this valley. The space across this valley is about 2,000 feet. 
 
 The ridge on the north side of the valley is covered by a gray (buff- 
 weathering) soil filled with stones and blocks of the gray argillites of 
 the Upper Etcheminian. This surface covering has a width on this 
 road of about 1,000 feet. After passing a wooded tract going towards 
 the Mira river, the soil is found to be filled with fragments of the 
 gray flags and slates of the middle part of the St. John terrane. 
 
38 
 
 The width of the Etcheminian terrane along this side of the Mira 
 valley for a distance of four miles on the strike is, at the 
 West Bengal road, 3,000 feet ; 
 East Bengal road, 5,000 feet ; 
 Boston road, 4,000 feet. 
 
 On the East Bengal road the bulk is increased by repetition of a 
 part or all of the Lower Etcheminian. 
 
 Wide tract of 
 Etcheminian 
 on Sydney 
 and Louis- 
 burg roads. 
 
 WITDTH OF THE ETCHEMINIAN ON THE SYDNEY AND LOUISBURG ROAD. 
 
 Mr. Fletcher gives data in his report which enable us to form an 
 estimate of the extent to which the Etcheminian is spread out in the 
 lower part of the Mira valley. He speaks of many outcrops of red and 
 gray argillites, &c., along the Sydney and the old Louisburg road, from 
 which it would seem that a width of two miles from a point near the 
 Albert bridge to the McMillan lakes is occupied by Etcheminian rocks. 
 And from these roads eastward to Mira gut, his descriptions would 
 show that the country, coloured as Silurian (i.e., Cambrian) is occupied 
 by the Etcheminian terrane. 
 
 Etcheminian 
 rocks around 
 the head of 
 Mira river. 
 
 OTHER AREAS OCCUPIED BY ETCHEMINIAN ROCKS. 
 
 There are other considerable areas coloured by Mr. Fletcher as 
 ■ Silurian (i.e. Cambrian) that are to be assigned to the Etcheminian 
 terrane. Where he speaks of red and green argillites, or sandstones, 
 or of conglomerates with felsite stones and grains, in the valley of the 
 Mira river, it is reasonably sure that the rocks belong to the Etche- 
 minian terrane. No rocks of the St. John terrane are indicated by 
 these names, as all these are gray of various shades, from pale gray 
 to almost black, or with a pale purplish tinge, and as a rule, they are 
 more fossiliferous. 
 
 South of the ridge of effusive and intrusive rocks that bound the 
 Mira valley on the south and east are outliers of stratified rocks which, 
 -from Mr. Fletcher's descriptions, appear to be Etcheminian. They 
 are conglomerates with some greenish-gray argillites. Mr. Fletcher's 
 description of the rocks on Canoe and Easg brooks, indicates that a 
 belt of Etcheminian sediments extends from the Bengal road along 
 the valleys of these brooks to the head of the Mira river above 
 Victoria bridge. 
 
 At the head of the Mira river on its western side is a considerable 
 stream in the valley of which are Etcheminian deposits, judging from 
 
39 
 
 the kind of rocks which Mr. Fletcher says occur there. This stream is 
 
 MoDougald brook, (Kelvin Brook of the Geological Survey map). The 
 
 rocks on this stream are described in the Report of Progress 1877-78 
 
 page 15 F. The large area of Etcheminian at the source of the Mira §°"f'* 9^ .*» 
 • ji !_ .,,.,. Etcheminian 
 
 river and along the eastern side of its basin, as well as the great sediments. 
 
 thickness they attain in this district, would indicate that they are 
 near the main source of supply of sedimentary matter available for 
 the building up of a geological terrane at that epoch. This source is 
 to be looked for in the extensive deposits of Ooldbrook effusives and 
 to ancient erosion of the pre-Cambrian crystalline rocks that inter- 
 vene between the Mira valley and the Atlantic ocean. 
 
 ST. JOHN TEEBANE. 
 
 Acadian Division. 
 
 The disturbed and complicated structure of the Cambrian terranes Slates of the 
 in the north-eastern end of the Barachois basin makes it diflS^cult to division in the 
 recognize the Acadian division here by its lithological features, and no Baroohois 
 fossils characteristic of the division have been found. There are, 
 however, two places where fine, dark gray slates occur. One is on 
 the road from George river station to the Barachois ; another is on 
 the Intercolonial railway, south-west of Young's farm. At the first 
 locality there are dark gray silicious slates a short distance from 
 George river station. They lie between the road and the syenite hill 
 to the east and dip N. 50° W. mag. < 45°. They are overlain in the 
 valley of Young brook by flags and slates of the Johannian division. 
 The other exposure of the slates of the Acadian division is along the 
 track of the railway as mentioned above, some distance south of 
 Young's house, at the foot of a slope of Etcheminian slates. This 
 band of Acadian slates runs diagonally up the hillside and crosses the 
 highway from George river station to Barachois. The rocks of this 
 division in the Indian brook valley are described in connection with 
 the next division of the St. John group. 
 
 On the east side of the Mira valley the Acadian division forms an Acadian 
 important part of the St. John terrane, and contains characteristic the Mka* °* 
 fossils. The rock there is a dark gray (purplish-gray weathering) clay- river and 
 slate, showing on the Bengal road. It contains lentiles or irregular 
 layers of carbonate of lime, in one of which a Paradoxides, resembling 
 P. rugulosus, a Ptychoparia, and a Palseacmsea (or Parmophorella) 
 were found. A considerable thickness of these measures also exists 
 on the west side of the Mira valley as seen at McLean brook near 
 
40 
 
 Marion bridge. Certain dark gray clay slates, which, by their position 
 appear to be of this division of the St, John terrane come in at the 
 head of the Mira river. They are seen where the road crosses Canoe 
 brook ; on the west side of the Mira river also, about three-quarters 
 of a mile south of the lime-kiln on the road near Salmon river, dark 
 gray shales, of this age occur. At the latter place the shales contain 
 Agnosti and some other fossils. It is probable that a belt of these 
 slates runs along the eastern flank of the 'Big Ridge,' on the east side 
 of the Mira river, connecting the outcrops on the Bengal road with 
 those near the mouth of Canoe brook. 
 
 Johannian Division. 
 
 Johannian Except a narrow band in the valley of Young brook near George 
 
 Long island river station, this group is first seen at the western point of a little cove 
 passage. inside of Young point, at the eastern end of the Long island passage. 
 
 A quite low cliff here consists of flaggy sandstones with some thin beds 
 of dark gray shale. They dip S.E. mag. < 30°. There are layers 
 covered with trails of Ctenichnites, burrows of Monocraterion and trails 
 and casts of worms ; also small, poorly preserved Lingulellas and an 
 Obolus. Between the Acadian beds and these are some heavy beds 
 of dark gray sandstone or quartzite. 
 
 Faulted in along the border of the Coldbrook felsites on the south- 
 eastern side of Long island and at the south-western end of the island 
 are certain conglomerates and sandstones of Cajabrian age. On the 
 south-east side of the ferry these sandstones dip S. 30° E. mag. < 80°, 
 and have ripple-marks and burrows of Arenicolites, &c. At the end 
 of the island the flaggy layers also show the pits and galleries of 
 Arenicolites, and dip S. mag. < 50°. The conglomerates contain 
 pebbles and boulders of weathered gray felsite, pale green slaty 
 felsite, and vesicular felsites similar to the rocks of the Coldbrook 
 terrane in this part of the island. They also contain fragments of 
 black flinty slate, like that of the pre-Cambrian terrane on the western 
 side of the island. 
 
 On the opposite side of the Long island passage the Johannian 
 division holds the shore from near Young point to the Long island 
 ferry, with prevailing dips to the south-east. The beds stand 
 mostly at high angles, and wave-marks and other indications show 
 Fossils. that some of them are overturned. They hold beds of small Lingu- 
 
 lellas, and a Beyrichia also occurs. Some of the flags have wave- 
 marks ; others are fretted with ripple-marks and worm trails ; others 
 again have burrows of Arenicolites and Monocraterion, and a few 
 have trails of Eoichnites. 
 
41 
 
 Wave ridges on slabs near the north end of Long island passage Wave 
 are transverse to a wave impulse from the north, others at the opposite ™*'^ '°^^' 
 end of this passage on Barachois harbour are' tranverse to a -wave 
 impulse from the west ; further south-west, along the shore of this 
 harbour, wave marks were observed transverse to an impulse from the 
 north-west. These different courses might indicate that Long island 
 was a barrier to the waves in^ Middle Cambrian time, but more obser- 
 vations are required to sustain such an hypothesis, for in the valley 
 of Indian brook, fourteen miles to the south-west of Barachois harbour, 
 wave-marks on the Johannian flags were found both parallel with and 
 transverse to the course of the valley through which that brook runs. 
 
 McMuUin brook, one of the feeders of Indian brook, is about two 
 
 and a quarter miles north-east of Dugald brook. It shows no section Johannian 
 
 of the Etcheminian terrane, but for the St. John terrane it supplies the Mullin brook 
 
 section which is wanting on the latter brook. It has a devious course, ™ Indian 
 
 , . /-I 1 • • orook valley. 
 
 but shows numerous beds of this part of the Cambrian rocks. As in 
 
 the case of Dugald and Gregwa brooks, there are falls where it descends 
 
 from the Cambrian plateau to the level of Indian brook; but, while in 
 
 the case of the two latter brooks the cascades are at the contact of the 
 
 Coldbrook effusives with the Etcheminian, on McMuUin brook it has 
 
 not cut so far back, but is toward the base of the Johannian division 
 
 of the St. John terrane. 
 
 This stream is instructive in giving a section of the entire Johan- 
 nian division which we did not meet with elsewhere in Indian brook- 
 valley. The Etcheminian terrane does not appear in this section, 
 because the stream for a furlong above the lowest outcrop of the 
 St. John terrane runs through an alluvial flat. The first beds seen, 
 greenish-grav sandstones, with a thickness of 35 feet, are perhaps of 
 the former terrane. (See map on next page.) 
 
 Following these are : — ?f'=JV°'5,9° 
 
 ° McMullm 
 
 30 feet hard gray conglomerate full of felsite pebbles. brook of 
 
 Acadian and 
 
 50 " measures concealed. Here the road crosses. Johannian 
 
 divisions of 
 
 37 " purplish gray felsite conglomerate, with fragments of the St. John 
 
 purple felsite, passing upward into purplish red sand- ^°"P' 
 stone. 
 
 38 " hard gray felsite conglomerate. 
 
 40 " compact gray sandstone. Dip S. 20° E. mag. < 65° 
 
 195 " Measures of the Acadian Division. 
 
42 
 
 felsice 
 
 Base 
 
 Slates 
 
 SECTION OFJOftANN/AN AND ACAU/AN 
 ON 
 
 M«MULLIN BROOK 
 ScaLe Sooy^bet: to one inch. 
 
45 
 
 75 
 
 1220 
 
 43 
 
 25 feet greenish gray conglomerate with felsite fragments and 
 felsitic sand. 
 
 fine-grained gray shale and earthy sand tone. Dip S. 40° 
 E. mag < 65° ? At the top of this band is a bed 
 of quartzite one foot thick, on the underside of which 
 are moulds of the burrows of Arenicolites, tracks of 
 worms, and trails of Ctenichnites (n, sp). 
 
 compact gray slate and some quartzite. Across two small 
 falls to the main fall of this brook. 
 
 same rocks in gorge below the fall. Here the flags have 
 wave marks 3 inches between crests. 
 
 similar rocks. Dip < 65°. 
 
 gray clay slate and flags. 
 
 same rocks. Claw marks of crustaceans. 
 
 same rocks, with wave-marked layers. Dip S. 25° E. 
 mag. < 80°. 
 
 gray slates and quartzites. High cliflf in the right bank. 
 same kind of rocks. Sides of the valley are lower, 
 measures concealed except some slates and flags in the 
 left bank. 
 
 intervale flat of Indian brook. 
 
 65 
 
 80 
 
 160 
 
 165 
 
 145 
 
 60 
 
 60 
 
 280 
 
 60 
 
 Measures of the Johannian Division. 
 
 On comparing this section with that on Boundary brook three miles Comparsd 
 to the south-west given on a former page, there appears a similar Tt Boundan' 
 series of felsite-conglomerates in the Acadian division of the St. John brook, 
 group, but as the intervening shales or slates and sandstones do not 
 correspond in thickness in the two sections, satisfactory correlation of 
 the conglomerates cannot be made ; the conglomerates, however, are 
 similar in kind and the difierence in thickness is not very great. In 
 the vicinity of the falls, both above and below them, the strata 
 exposed are characteristically those of Division 2 Johannian, and 
 contain trails of Ctenichnites, and trails and burrows of worms, such 
 as are met with in the rocks of this division elsewhere. The group, 
 however, shows a much greater width here than on Boundary brook, 
 where a large part of its mass is out out by the great fault running 
 along the east side of Indian brook valley. At McMuIIin brook this 
 division shows a full thousand feet in thickness of measures, and is 
 thus as bulky as in typical sections in the city of St. John in New 
 Brunswick. 
 
44 
 
 Plumbaginoua At the aiouth of Dugald brook, a little further down the valley, a 
 mouth of narrow band of black plumbaginons slates shows itself next the granite. 
 Dugald brook. These would belong to the Bretonian division, so that there is reason 
 to suppose that this twelve hundred feet of the section on McMullin 
 brook represents the whole of the Johannian division as it is developed 
 in the Indian brook valley. An examination of Indian brook from 
 the mouth of Dugald brook downward shows little beside the Johan- 
 nian division. For two miles, or as far as the highway bridge, the 
 channel runs close to the foot of a high ridge of pre-Cambrian syenite, 
 with exposures of flags, quartzites and arenaceous slates in the bottom 
 of the valley. They vary somewhat in strike, but generally this is 
 parallel to the course of the stream. 
 
 On Indian These beds are sometimes overturned, as is shown by the worm- 
 
 are ripple burrows and wave marks on the flags. The ripples are occasionally 
 marked flags. pu-^Hel to the course of the stream (and valley) and at other times at 
 right angles to it. No such wave-marks could have been produced by 
 waves transverse to the course of this narrow valley, if the contour of 
 the land had then been such as it is now. The hills which bounded 
 the valley in Etcheminian time had at this epoch of the Cambrian 
 pissed below sea-level, and the Cambrian deposits made in it were 
 subject to the mouldiag influence of the ocean waves. 
 
 Cambrian Below the highway bridge the Cambrian flags and quartzites form 
 
 depressed be- an anticlinal fold, of which the eastern slope is depressed "toward the 
 
 tween syenite . . , ,i. 
 
 ridges. southern syenite ridge, and the western is cut ofi^ by an encroaching 
 
 syenite ridge on the opposite side of the valley. These two ridges meet 
 a mile above the mouth of the stream, so that the Cambrian basin 
 terminates here abruptly. As neither the Coldbrook nor the Etche- 
 minian terranes are seen at this end of the valley, and as the lower 
 division of the St. John terrane is not in view, the whole Cambrian 
 must here have sunk many hundred feet along fault lines into the pre- 
 Cambrian complex. 
 
 Johannian -^ limited outcrop of the flags of the Johannian division is found at 
 
 division at Mcintosh brook on East bay, half a mile above its mouth. It con- 
 brook, sists of gray flags and shales in frequent alternations; dip S. 10° E. 
 mag. < 70°. Loose pieces of the flags contain Lingulella (sp ) and 
 more rarely Acrothele (sp). Resting on these are gray rubbly shales, 
 soft and micaceous, with Arenicolites and other worm burrows. They 
 are cut oflf at the left bank by the crystalline volcanic rock mentioned 
 by Mr. Fletcher. The Cambrian area is small and no other part of 
 the Cambrian terranes were seen here, as overlying Lower Carbonifer- 
 ous limestones and shales conceal their extension. 
 
45 
 
 JOHANNSAN anoBRETONIAN 
 
 AT 
 
 GILLIS' BROOK, EAST BAY 
 Senile looq/het ^ one cnjc/ty 
 
46 
 
 Etcheminian 
 at Spruce 
 brook. 
 
 Cambrian 
 strata on 
 Gillis' brook. 
 
 Worm bur- 
 rows and 
 rippled flags. 
 
 Bretonian 
 division. 
 
 Section of 
 Johaunian 
 at McLean 
 brook, Mira 
 
 There is a considerable area of Cambrian rocks near the head of 
 East bay, on its northern side, which was examined ; it extends from 
 Spruce brook to Gillis brook. At the first brook, exposures are 
 limited in extent in the western tongue of a basin covered on the 
 east and south by Lower Carboniferous deposits. On the west branch 
 of Spruce brook at the foot of the granite hills are purplish gray 
 sandstones containing valves of Lingulella and Aorotreta ; these beds 
 dip N. 10° E mag. < 50° ; they may be assigned to the Lower 
 Etcheminian. There are some beds of felsite and of felsite-grit inter- 
 calated with these sandstones. 
 
 An examination of the Cambrian areas on Gillis brook was made 
 above and below the point where the Coxheath road crosses it. (See 
 map on preceding page.) At this point there is a width of 2,000 feet 
 or more of the Johannian division, much folded and crumpled. Above 
 the bridge at the Coxheath road there is a large quantity of gravel 
 and boulders along the stream and the ledges are seen only at intervals. 
 Below the bridge the stream has cleaned out its valley, and runs with 
 a tortuous course through a ridge of quartzites and flags to a flatter 
 tract where it has a more regular flow through rounded hills of black 
 and dark-gray shale of t he Bretonian division, whose measured have a 
 width on the surface of 1,500 feet. 
 
 Below this the stream crosses another band of the gray flags of the 
 Johannian division and again becomes more tortuous, with high banks 
 until it meets Lower Carboniferous feldspathic conglomerates. The 
 flags and slates have worm galleries of Arenioolites and pits marking 
 the lairs of Monocraterion. Ripple-marked and wave-marked flags 
 are present here, with spaces of three to five inches between the crest 
 of the wave ridges. In the dark gray shales of the Bretonian division 
 further up stream there are a few thin limestone beds and lentiles, in 
 one of which valves of Orthis lenticidaris are plentiful. 
 
 The lower part of the St. John group was not seen, nor was any 
 older Cambrian terrane observed, this Cambrian area being separated 
 on both sides from the pre-Cambrian rocks by Lower Carboniferous 
 deposits. The best section of the Johannian division of the St. John 
 terrane in the Mira valley is that exposed on McLean brook, near 
 Marion bridge. This section has been exploited by Mr. S. Ward 
 Loper, who has collected there extensively for the United States 
 Geological Survey. (See map on opposite page. ) 
 
 Here the whole series of the flags and slates of this division are 
 exposed in the valley of the brook, which cuts across them transversely. 
 They dip down the stream at an angle of 70° to 50° and rest upon 
 
47 
 
48 
 
 Paradoxides 
 in this divi- 
 sion. 
 
 Curving 
 course of 
 measure on 
 McLean 
 brook. 
 
 Johannian 
 division in 
 Mira valley 
 concealed by 
 heavy cover- 
 ing of drift. 
 
 about 150 feefc of dark gray slates of the Acadian division, of which 
 the base is concealed by surface deposits and woodlands. 
 
 Of the Johannian there are about 1,060. Of this thickness 365 
 feet in the lower part may be assigned to the section a ; in it there are 
 some heavy quartzite beds which have given rise to a fall on the upper 
 part of the stream ; the lower half of this, above the falls, has much 
 dark slate interstratified. 
 
 The middle section b, of about 455 feet, is mostly composed of flags 
 and slates, and is more fossiliferous; a Lingulepis allied to L. Starri of 
 the corresponding horizon in New Brunswick, is quite plentiful ; and a 
 Beyrichia, Beyrichia triceps, n.sp., with a high anterior ridge on the 
 valve, occurs. In the upper part of this section Mr. Loper found a few 
 examples of a variety of Paradoxides Forchhammeri. It differs from 
 the typical form in being smooth on the glabella, but it is warty on 
 the slope of the cheeks like that form. 
 
 The upper section (c) of about 245 feet is composed of softer and 
 more micaceous flags and slates, in which fossils were not found so 
 abundantly ; those that occur are of smaller size than the species of 
 the middle band. Following these and resting upon them are black 
 and dark-gray fine, soft, crumbling slates that have a considerable 
 width, and are the last rocks exposed in going down the stream. 
 These would belong to the Bretonian division. 
 
 The section of this brook shows the same curving of the strata 
 around the McCodrum ridge as Mr. Fletcher noticed in t^e Etche- 
 minian terrane on McCodrum brook. In the lowest exposures of the 
 dark gray Acadian slates on the upper part of McLean brook the dip is 
 S. 40° E. mag. ; at the falls in the quartzites, etc., of the lower section 
 (a) it is S. 60° E. mag. ; higher measures of the same section return 
 to S. 40° E. mag. ; in the middle section the dip varies from S. 5J° E. 
 mag. to 40° E. mag. ; in the upper part of this section it changes to 
 S. 20° E. mag., and so continues to the top of the Johannian division. 
 The change of strike is about forty degrees, which agrees with the 
 change observed by Mr. Fletcher on McCodrum brook. 
 
 The sections of the beds of the Johannian division, seen elsewhere 
 in the Mira valley, are so partial, owing to the heavy drift covering in 
 this valley, that no satisfactory proof of the thickness of this member 
 was met with, other than in this section, but it will be noticed that 
 this section agrees nearly in the thickness of the beds with those 
 exposed on McMuUen brook in the Indian Brook valley. 
 
49 
 
 But though there are no clear sections of this division in the Mira 
 valley that have come under our observation, except at McLean 
 brook, there is ample evidence that it is w«ll developed there. In the 
 centre of the valley is an important settlement known as ' Big Ridge,' 
 ■which is spread along the principal ridge of Johannian rocks in this 
 valley. It lies between McNeil brook and Trout brook, and extends 
 to the old French road. On each side of this main ridge are two Ridges at Mc- 
 other lower swells of the same rocks, one iaUing in the space between ^^'^ ^'^°°^' 
 McNeil brook and the Mira river (except the narrow belt of Bretonian 
 shales extending along the course of McNeil brook), the other lying 
 In the valley of Trout brook. The rocks of these several ridges meet 
 along the Mira river, which is bordered by Johannian flags and s'ates 
 from Marion bridge well down toward Albert bridge. 
 
 The Bretonian Division, 
 
 In the Barachois valley, at the railroad cutting on the east side of 
 the Barachois pond, a considerable thickness of fine, dark, soft clay 
 slates is exposed. These are the first measures going south and east Bretonian 
 of the Bras d'Or met with in Cape Breton, that can with certainty be BaSok' 
 assigned to the Bretonian division of the St. John group. At the ''°*'^- 
 east end of the cutting they dip S. 40° W. mag. < 5°; about the 
 middle of the cutting their dip is S. 30° W. mag. < 10°. Here there 
 is a small synoline, and at the further end of the cutting the dip is 
 increased to S. 30° E. mag. < 50°. Although there are some rows of 
 small calcareous lentiles in these beds, by which the dip was deter- 
 mined, no fossils were found in them. 
 
 McLeod brook enters the upper end of Barachois pond. Following 
 up this brook, no other part of the St. John terrane is met with besides 
 these soft dark slates. The valley along here is bordered by syenites 
 on the south-east and by effusive rocks on the north-west. But near 
 the bead of the valley the Etcheminian sandstones previously referred 
 to form a narrow border for a short distance on the north-west side. 
 In ascending McLeod brook from the Barachois pond the dip of the Bretonian 
 Bretonian slates, where it has been observed, for a distance of two aad Leod brook ' 
 a half miles up stream, i^ Low — 10 to 30 degrees ; then the beds stand 
 at higher angles and mostly dip tovard the south-east side of the valley ; 
 but in X3i^iier pafts they also dip south-west and north-west. At 
 Johnson's little brook, which comes down over a cliff of syenite, thwe 
 is a thin bed of limestone containing shells of Orthis lenticularis and 
 a Camarella (?) ; this limestonB is contained in black carbonaceous 
 shale. Mr. Fletchw found Dictyonema flaheUiformis here. 
 4 — c. R. 
 
50 
 
 Tremadoo 
 fossils on Mc- 
 Leod brook. 
 
 General up- 
 ward succes- 
 sion from 
 George river 
 station to 
 head of Mc- 
 Iieod brook. 
 
 Differential 
 uplift of the 
 north-eastern 
 end of the 
 Barachois 
 basin. 
 
 About half a mile below the Boisdale road bridge, McMuUins little 
 brook enters the main brook on the right. On this brook a short dis- 
 tance above its outlet are gray shales containing Monoholina refulgens, 
 Schizambon priseus and parts of trilobites. At the bridge the same 
 fossils and others occur in a shale bank on the right side. At Mc- 
 MuUin's brook the dip is S. mag. and S. 40° E. mag. < 70° and 80°. 
 About a quarter of a mile above the bridge is another shale bank on 
 the right side having limestone lentiles with Monoholina refulgens 
 and a Lingulella ; here the dip is S. mag. < 60°. About a furlong 
 below the bridge in the left bank a thin fossiliferous band crops 
 out, dipping at a high angle, and carrying Asaphellus cf Homfrwyi, a 
 Triarthrus, a Paraholinella and other forms of the Tremadoc faunal 
 Other exposures with fossils are found in this bank of the stream, 
 further up. 
 
 It will be observed that the dip in this part of the valley is 
 quite variable, but the rocks are not strongly cleaved, as they are at 
 the Barachois. Notwithstanding the confusing dips and faults in some 
 parts of the Cambrian terranes in the basin extending from George 
 river station to the head of McLeod brook, one can note a general 
 succession of the parts of the Cambrian system from the former to the 
 latter place. 
 
 Prom the station named, where the oldest Cambrian sedi- 
 ments of this basin rest on the Coldbrook felsites and pre-Cambrian 
 syenite, to Young point at the entrance of the Long Island passage, 
 the rocks are Etcheminian. Behind this point the first division (Aca- 
 dian) of the St. John group is cut out by a fault, but the middle 
 division (Johannian) holds the shore of the eastern side of Long Island 
 passage, to the head of Barachois harbour. Here it disappears beneath 
 the upper, or Bretonian division, which extends thence to the narrow 
 deep gorge at the French Vale read, near the source of McLeod 
 brook. This arrangement would imply a differential uplift of the 
 north-eastern end of the basin since Cambrian time, through which 
 the whole of the terranes at this end of the basin have been eroded 
 to the basal conglomerates. Complementary to this there has been a 
 depression at the south-western end with the production of heavy 
 faults on both sides of the Cambrian valley, by which the terranes 
 have been let down between the bordering pre-Cambrian ranges for 
 the whole thickness of the three terranes which constitute this system 
 in Cape Breton. 
 
 Very different conditions and structure prevailed in Indian brook 
 valley, which is a nearly direct continuation of the Barachois basin. 
 
51 
 
 Por the greater part of the length of this valley the measures aie Cambrian 
 nearly or quite vertical and the succession of the Cambrian terranes i^tndS^*'*' 
 is from side to side of the valley, i.e., from the northwest to the south-east ^""^^ ^*^«y- 
 side, and the whole series may be crossed in the distance of three- 
 quarters of a mQe. But the series is not complete, as the Bretonian 
 division is almost or quite removed by faulting and erosion from every 
 section in this valley which it has been possible to examine, and the 
 elisions on some sections cut out half the Jehannian division as well. 
 
 A few miles to the south-east of Indian brook basin, on the shore Peltura fauna 
 of East bay, there is a small outcrop of Bretonian shales and thin Cs^' ^^~ 
 flags, (surrounded by Lower Carboniferous shales with gypsum) that 
 carry a characteristic fauna. Here were found Sphcerophthaltnus 
 Metcheri, Pardbolina Dawsoni, Pdlura scarabeoides, Agnoslus tri- 
 sectus, and other forms of the Peltura fauna. Nearer the head of 
 East bay, but inland from it on Gillis' brook, is the band of Bretonian 
 shales already described, containing limestone layers with Orthis 
 lenticularis, &c. 
 
 Two basins of Bretonian slates have been recognized in the valley of Two basins of 
 the Mira river. One lies in the depression above Marion bridge where slates in valley 
 the river widens out and takes on a lake-like appearance known as the * "^^^ 
 
 ' Grand Mira.' This basin lies between Johannian sediments on 
 McLean brook and a low broad ridge of rocks of the same age that 
 extends from Marion bridge some distance up along the right bank of 
 the ' Grand Mira ' ; the basin extends in a north-easterly direction 
 where it passes beneath an area of Millstone grit of the Carboniferous 
 system. The other basin is a narrow one on McNeil brook, a stream 
 discharging into the Mira river on the eastern side below Marion 
 bridge. This basin is pinched out on McNeil brook a little below 
 where the bridge of the Trout brook road is placed. It forms a 
 narrow trough extending along McNeil brook to and beyond the 
 bridge where the 'Big Bidge ' road (on the Geological map, the Cari- 
 bou Marsh road), crosses. Beyond this point it has not been traced, 
 but it may extend through a valley that runs along the north-western 
 side of the Big Ridge and by McEchern's lake and brook connects 
 with the ' Grand Mira.' It was from this basin on McNeil brook Fossils of the 
 that the fossils were obtained which first showed the existence of 
 Cambrian rocks in Cape Breton. The fossils from this basin, found 
 on McNeil brook, are Peltura scarabeoides, Spharophthalmus alatus 
 and several Agnosti and Lingulellse. 
 
 The area covered by Bretonian rocks in Cape Breton is insignificant 
 compared with that occupied by Johannian or Etcheminian sedi- 
 4J— C. R. 
 
52 
 
 ments. This is O'wing partly to their being of less volume originally, 
 for they cannot be estimated at more than 500 to 700 feet in any of 
 the three basins where they are so exposed that an approximate esti- 
 mate can be made. But probably the chief reasons of the rarity of 
 exposures of this part of the St. John terrane, are the softness of the 
 slates or shales of which the division is composed, and to the fact that 
 they form the uppermost division of the terrane, and therefore were 
 the first to come under the destructive action of abrading agencies. 
 
 Approximate A. more careful examination of the field is necessary before a reli- 
 
 thicknesB of . ,.ii-. p , A t 
 
 the Cambrian able estimate could be given of the thickness of the Cambrian rocks 
 
 ^oe'sreton ^^ Cape Breton, and the following are to be regarded as only an ap- 
 proximate estimate of their thickness. 
 
 East Bay Mira Valley. 
 
 Coldbrook terrane 300 Very thick. 
 
 Etcheminian terrane 500 3,000 1 
 
 St. John terrane, viz : — 
 
 Acadian division 200 800 ? 
 
 Johannian division 1,200 2,000 ? 
 
 Bretonian division 500 ? 500 ? 
 
 2,700? 6,300? 
 
 ORIENTATION. 
 
 Having observed a remarkable uniformity in the attitude of the valves 
 of Brachiopods buried in the Etcheminian sediments of Indian Brook 
 basin on the East Bay of the Bras d''Or, it occurred to the writer that 
 an investigation of the causes that led to this would throw light on the 
 physical history of the Cambrian deposit in relation to the life of that 
 period. 
 
 Attitude of Ijj tlje following remarks I shall use the term orientation to express 
 
 the valves of .,.?.,, p i , , ^ , . , 
 
 the Braehio- the attitude in which the valves of the brachipods are found, when 
 
 P° opened up on the layers of the rook over which they are spread. The 
 
 loesJf of thjB ventral valves is found to point so uniformly in one 
 
 directioQ that it can only be the result of gome general cause which 
 
 has acted on these vjilves wheij living, or when about to be buried in 
 
 th.» Jnud oo th«e sea-hottom. 
 
 These brachiopods when living would. Ifiave been attached to the 
 bottoei by the pedipje or anchoring thread, a§ in the modern Lingula, 
 bj),t 'v^ere- fre^ tbus to float in the sea water near the bottom. The 
 great majority of the shells buried in the Etchemibian sands and 
 
03 
 
 clays belong to the orders Atrefitota and Neotremata, both of which Mostly of the 
 have representatives in the oldest Catobfian bedsi la both, the matTand"^^ 
 pedicle must have had much durability, as it succeeded in holding Neotremata. 
 the shell in position in a majority of cases until th® latter was 
 weighted down with the accumulating sediment falling from th« 
 turbid water. 
 
 The pedicle is an organic part of the animal and is composed of Importance of 
 layers of chitinous and fleshy matter and is liable to decay on the relafion to^ "^ 
 death of the animal. Orientation presupposes that the pedicle lasted orientation, 
 long enough to hold the shell in position until it was buried. The con- 
 ditions in the Etcheminian beds show that the dorsal valve after the 
 death of the animal and the decay of the museles aad ligaments might 
 float off, and yet the ventral value would be held firmly in its place, 
 presumably "with tile aid of the pedicle. All braehiopods do not have 
 pedicles of equal strength and durability ; this is clear BiS regards the 
 Etcheminian forms, for some genera show greater susceptibility to 
 orientation than others, and it may be noted that it is the larger 
 species in which the orientation is more apt to be obscure. Outside 
 of the influence of the pedicle, form seems to have a good deal to do 
 with the attitude of the valves. This is manifest from the position 
 assumed by shells of the genera Obolus* and Leptobolusf in certain 
 layers of the Upper Etcheminian, for while only 33 p.c. of the valves 
 of the former are oriented, 81 p.c. of the latter have yielded to the 
 influences causing orientation. No genus shows more perfectly the Aef^^i>a 
 influence of form on orientation than AcrothyraJ entombed in the oriented, 
 same beds with the above genera ; in this genus 84 p.c. of the funnel- 
 shaped ventral valves are affected by orientation, while this phenome- 
 non can scarcely be traced in the attitude of the saucer shaped_dorsal 
 valves. 
 
 Leaving out of view the influence of the pedicle in holding the 
 valves in a certain position while being entombed, it is easy to see that 
 form has much to do with the phenomenon of orientation. We have 
 seen how diverse in shape were the two valves of Acrothyra, and how 
 differently the two valves acted in the process of burial, and that while 
 the ventrals exhibit a high percentage of oriented valves, the dorsals 
 show scarcely more than the natural quarter of their number so placed ; 
 we may on the contrary see how readily the valves of Leptobolus have 
 responded to the causes producing orientation. In this genus both 
 valves are oval and nearly alike, and this contour would favour the 
 placing of the valves lengthwise in the line of the current of water in 
 
 * Obolus lens. t Leptobolus atavua. J Acrothyra proavia. 
 
54 
 
 which they lived, as being the position of least resistance. So it 
 happens that both dorsal and ventral ^valves can be included in the 
 record of orientation, without materially affecting the percentage ; 
 while to follow the same plan with Acrothyra would reduce the per- 
 Lejjtobolua centage of oriented valves nearly one-half. Yet we notice that in 
 oriented. Leptobolus there is a much larger proportion of reversed valves than 
 
 in Acrothyra ; that is of valves having the longer axis parallel to the 
 direction of the flow of the orienting current, but with umbo, in 
 place of the front of the valve, pointing in that direction. These 
 reversed valves we regard as affected by orientation, but not oriented. 
 
 Their abundance in Leptobolus as compared with Acrothyra may be 
 due to one of two causes. In Acrothyra the umbo was strong and 
 heavy and in cases where the pedicle had perished, and the ventral 
 valve sank to the bottom the point of the shell would touch first and 
 the shell would swing on this as on a pivot, presenting its smallest and 
 heaviest end to the force of the current. Another cause which might 
 have helped to cause the diversity in the attitude of the valves of 
 the two genera is that the umbonal region of the ventral valve in 
 Leptobolus was thin and the pedicle correspondingly attenuated ; if 
 it perished readily the valve would be sooner at the mercy of the 
 current, and so would orient with either end presented to the current, 
 indifferently. 
 
 Obolus scarce- I^i Obolus we note a genus which resembles Leptobolus in the incon- 
 ly affected by spiouousness of the umbo of the ventral valves, but differs in having 
 flatter valves which are circular ; and although the valves are thicker 
 and heavier, the weight is somewhat evenly distributed. These nearly 
 round saucer-shaped valves have left but a very imperfect record of 
 orientation, for in the lot examined one-third were oriented and 28 
 per cent reversed, thus 39 per cent show entire indifference to the 
 course of the orienting current. 
 
 There are a few valves of Acrothele, but they are insufficient to be 
 of value in this question of orientation. But, having in view the two 
 genera first discussed, I think these clearly show a current passing in 
 a north-east direction through Indian Brook valley when the Etche- 
 minian terrane was being formed. At the same time there seems to 
 be abundant proof of shore lines near at hand from wliich felsitic stones 
 and sand were derived, and from which the felspathic sand and mud 
 were swept that rapidly entombed these shells. 
 
55 
 
 ORiENTiTiON of Brachiopods on 10 small slabs from the Assise E. 3 e. Oriented 
 
 fossils in E. 3 e. 
 
 N.B. — Valves with umboes pointing 
 S.W. are oriented ; N.E., reversed. 
 
 Oriented. 
 
 Reversed. 
 
 Point 
 
 S.E. 
 
 Point 
 N.W. 
 
 Oholus tens— 18 valves. 
 Oriented 33 % 
 Reversed 28_%» 
 Pointing S.E. 17 % 
 N.W. 22 % 
 
 1 
 1 
 
 2 
 
 2 
 
 2 
 
 1 
 2 
 
 1 
 1 
 
 1 
 
 2 
 
 1 
 1 
 
 
 6 
 
 5 
 
 3 
 
 4 
 
 LiptaholMS, chiefly oMvm. 
 
 Both valves, 127 valves. 
 Oriented 53 % 
 Reversed 28 % 
 Pointing S.E. 11 % 
 Pointing N.W. 8 % 
 
 22 
 9 
 " 8 
 9 
 8 
 7 
 4 
 1 
 
 7 
 3 
 6 
 5 
 5 
 4 
 1 
 4 
 
 4 
 
 4 
 
 1 
 4 
 
 1 
 
 6 
 2 
 
 1 
 1 
 
 
 68 
 
 35 
 
 14 
 
 10 
 
 Acrothyra proavia. 
 
 Ventrals only, 158 valves. 
 Oriented 72 % 
 Reversed 12 _% 
 Pointing S.E. 12 % 
 „ N.W. it 
 
 16 
 12 
 
 7 
 
 3 
 13 
 18 
 14 
 
 6 
 18 
 
 7 
 
 6 
 1 
 6 
 
 3 
 
 2 
 
 1 
 
 5 
 1 
 
 1 
 8 
 
 1 
 3 
 
 3 
 
 1 
 
 1 
 
 1 
 
 
 114 
 
 19 
 
 19 
 
 6 
 
 Acrothele avia. 
 
 Both valves, 2 valves. 
 
 1 
 
 1 
 
 
 
 The rock in which these fossils occur is gray and of fine texture and 
 show a strong tendency to split along certain lines which are the 
 layers where fossils are most abundant, and where the surfaces are 
 lavishly strewn with little shells. 
 
 Finding such marked orientation in the valves of Assize E. 3 e, 
 it was thought desirable to see if other horizons of the Etcheminian 
 presented similar conditions and at another locality, so a test was 
 made of some small slabs from the Assize E. 1 (i on Boundary brook. 
 The following table gives the result: — 
 
Oriented 
 Lingulepi4eB 
 in Assise K 1 
 d, Boundary 
 brook. 
 
 56 
 
 Orientation in eleven small slabs showing Brachiopods from 
 Assise E. 1 d. at Boundary brook. 
 
 
 Oriented. 
 
 Reverted. 
 
 Point. 
 S.E. 
 
 Point. 
 N.W. 
 
 Lingulepides, chiefly L. Oregwa from the 
 lowest Etoheminian fossiliferous hori- 
 zon on Boundary brook — 100 valves. 
 Oriented 56%. 
 Reversed 16%. 
 Pointing S.E. 11%. 
 „ N.W. 17>„. 
 
 5 
 8 
 9 
 7 
 3 
 4 
 4 
 5 
 4 
 4 
 3 
 
 2 
 
 4 
 2 
 4 
 
 2 
 
 1 
 1 
 
 2 
 
 2 
 
 1 
 2 
 
 1 
 2 
 
 2 
 5 
 1 
 
 2 
 2 
 2 
 2 
 
 1 
 
 
 56 
 
 16 
 
 11 
 
 17 
 
 Returning to Dugald brook I continued the examination of the 
 assises there. Four small slabs from the Assise E. 1 c did not show- 
 such satisfactory results. The species here are Acrothyra signata, and 
 a few examples of an Obolus. The Acrothyrse, unlike those of Assise 
 E. 3 e, do not lend themselves to orientation. Many are in a vertical 
 or nearly vertical position (in relation to the layers of rock) and not 
 thrown on their sides like those of the horizon last named. 
 
 Acrothyra 
 oriented in 
 Assize E. 1 c. 
 
 Orientation in Assise E. 1 c. at Dugald brook. 
 
 
 Oriented. 
 
 Reversed. 
 
 Point 
 S.E. 
 
 Point 
 N.W. 
 
 Acrothyra signata, chiefly the mutation 
 gera. 
 
 All ventral valves, 34 valves. 
 Oriented 41%. 
 Reversed 29%. 
 Pointing S.E. 15%. 
 N.W. 153^. 
 
 3 
 7 
 2 
 2 
 
 4 
 3 
 1 
 2 
 
 1 
 1 
 1 
 2 
 
 2 
 2 
 1 
 
 14 
 
 •10 
 
 5 
 
 5 
 
 These and the following table give the best examples of orientation 
 in, the Lower Etcheininian, but in others of these lower assises it was 
 not at all well marked. Taken collectively the assises of the Lower 
 Etcheminian do not exhibit by any means so okar an exemplification 
 of the phenomina of orientation as those of the Upper Etcheminian. 
 
57 
 
 Some small slabs were tested from Dugald brook from the same 
 assise as those above mentioned on Boundary brook. These show a 
 more decided orientation than the preceding : — 
 
 Oeientation in four small slabs — Assise E. 1 d. 
 
 
 Oriented. 
 
 Reversed, 
 
 Point 
 S.E. 
 
 Point 
 
 
 N.W. 
 
 -Xingvlepis Gregwa. 
 
 Ventral valves, 18 valves. 
 Oriented 56%. 
 Reversed 11%. 
 Pointing S.E. 11%. 
 .. N.W. 22%. 
 
 2 
 3 
 3 
 
 2 
 
 1 
 1 
 
 1 
 1 
 
 2 
 
 1 
 1 
 
 10 
 
 2 
 
 2 
 
 4 
 
 JAnguiepis Oregwa-robueta— 
 Both valves, 39 valves. 
 Oriented 66%. 
 Reversed 21%. 
 Pointing S.E. 8%. 
 .. N.W. ^. 
 
 5 
 " 9 
 
 5 
 7 
 
 3 
 2 
 
 2 
 
 1 
 
 1 
 
 1 
 
 1 
 
 1 
 1 
 
 26 
 
 8 
 
 8 
 
 2 
 
 Lingulepides 
 oriented in 
 Assise E. 1 d, 
 Dugald brook. 
 
 The ventral valve is thicker and is more regularly conical in this 
 variety than in L. Gregwa ; these differences may have helped to give 
 this form a more pronounced orientation than the L. Gregwa type. 
 
 Between the Gregwa shale and the top of Division 2 of the Etche- 
 minian, coarse sediments prevail; brachiopods are scarce and give no 
 data bearing on the orientation of the valves. But in some of the 
 lower seams of Division 3, fossils are again numerous, and again show Acrothyfa 
 the effect of the orienting current. Here a new fauna comes in, but Assise E. 3 a. 
 at first sparingly. 
 
 Orientation of fossils on a small slab from Assise E. 3 a. 
 
 
 Oriented. 
 
 Reversed. 
 
 Point 
 S.E. 
 
 Point 
 N.W. 
 
 Aerothyra proavia, ventrals. 
 " dorsals. 
 
 4 
 1 
 
 3 
 
 3 
 3 
 
 1 
 
 1 
 
 
 5 
 
 3 
 
 6 
 
 2 
 
58 
 
 Here, as elsewhere, the dorsal valves of Acrothyra give no indica- 
 tions .of value as to orientation, but the high, prostrate ventral valves 
 do. A bed in this assise gave the following result : — 
 
 Other fossils ORIENTATION of valves on four slabs, layers from one inch to half an 
 lllfsl^ e!°3 a. i^cb apart, in the Assise B. 3 a. 
 
 
 Layer. 
 
 Oriented. 
 
 Reversed. 
 
 Point 
 
 S.E. 
 
 Point 
 N.W. 
 
 Acrothyra proavia-prima, ventra] 
 valves. 
 Oriented 56% 
 Reversed 10% 
 Point S.B. 13% 
 Point N.W. 21% 
 
 1 
 
 2 
 3 
 
 4 
 
 4 
 39 
 62 
 32 
 
 
 
 5 
 12 
 
 7 
 
 5 
 
 13 
 
 6 
 
 8 
 
 13 
 30 
 
 1 
 8 
 
 
 — 
 
 137 
 
 24 
 
 32 
 
 52 
 
 Dorsal valves. 
 dolus lens, both valves. 
 Oriented 60% 
 Reversed 13% 
 Point S.B. 20% 
 Point N.W. 7% 
 
 4 
 
 17 
 
 17 
 
 16 
 
 11 
 
 1 
 2 
 3 
 
 4 
 
 2 
 1 
 1 
 5 
 
 1 
 
 1 
 
 3 
 
 1 
 
 
 — 
 
 9 
 
 2 
 
 3 
 
 1 
 
 The dorsal valves, on one slab, of Acrothyra are recorded to show- 
 how little they were affected by orientation. These slabs show an 
 unusual number of oriented Obolus ; many of these were young valves. 
 In the next assise above, orientation is well marked, as shown below : — 
 
 Orientation of 
 three genera 
 in Assise B. 
 3 6. 
 
 Orientation in five small slabs from Assise E. 3 6. 
 
 
 Oriented. 
 
 Reversed. 
 
 Oriented. 
 
 Reversed. 
 
 Point 
 S.B. 
 
 Point 
 S.W. 
 
 Obolus lena,hoth valves 
 LeptoboVus atavus, both 
 
 valves. 
 Lingulella. 
 Acrothele abavia. 
 
 33% 
 
 ^ 
 
 50% 
 
 21% 
 32% 
 
 2 
 
 13 
 
 2 
 
 11 
 
 4 
 
 7 
 
 2 
 
 1 
 1 
 2 
 
 2 
 
 1 
 2 
 
 
 28 
 
 11 
 
 6 
 
 5 
 
 Here Acrothele exhibits orientation to an unusual degree ; but in 
 other cases its round valves are found buried in the mud in all atti- 
 
59 
 
 tudes. Leptobolus shows the usual large percentage of oriented and 
 reversed valves. 
 
 In the next assise are layers, over which are scattered the valves of 
 Acrothele and an oval Leptobolus. The attitude of these valves is as 
 follows : — 
 
 Orientation of valves on three small slabs of Assise E. 3 c. 
 
 
 Ori- 
 
 Ke- 
 
 Ori- 
 
 Re- 
 
 Point 
 
 Point 
 
 
 ented. 
 
 versed. 
 
 ented. 
 
 versed. 
 
 S.E. 
 
 N.W. 
 
 
 % 
 
 % 
 
 
 
 
 
 Acrothele abavia. 
 
 50 
 
 25 
 
 4 
 
 2 
 
 1 
 
 1 
 
 Leptobolus coUieia. 
 
 78 
 
 13 
 
 35 
 
 6 
 
 2 
 
 2 
 
 
 39 
 
 8 
 
 3 
 
 3 
 
 Fossils 
 oriented in 
 Assise E. 3 c. 
 
 The second species here is more like a lingulella in form than the 
 Lieptobolus in the assise below, and responded correspondingly to the 
 orienting force. 
 
 Orientation in the next assise shows similar conditions, but with 
 other species. 
 
 Orientation of valves on several small slab? from Assise E. 3 d. Orientation of 
 
 two genera 
 
 in Assise E. 
 3d. 
 
 
 Oriented. 
 
 Reversed. 
 
 Point 
 S.E. 
 
 Point 
 
 N.W. 
 
 Leptobolus atavus. 
 Both valves. 
 Oriented 59% 
 Reversed 21% 
 Point S.E. 9% 
 Point N.W. 11% 
 
 6 
 3 
 3 
 
 4 
 2 
 
 8 
 
 1 
 
 1 
 
 1 
 1 
 5 
 
 
 
 
 1 
 
 3 
 1 
 
 
 4 
 
 
 26 
 
 9 
 
 4 
 
 5 
 
 Acrothyra proavia, ventrals 
 
 5 
 
 2 
 
 2 
 
 1 
 
 
 
 
 
 
 Oriented 50%. Reversed 20%. Point S.E. 20%. Point N.W. 10%. 
 
 Here the proportion of oriented ventral valves in Acrothyra proavia 
 is unusually low. 
 
60 
 
 A description of the orientatioa features in the bra/chiopods of the 
 next assise has been given on a previous page. There remains to record 
 the result of observations on the fossils of the highest Etcheminian 
 assise — E. 3 /! 
 
 Orientation of ORIENTATION in the valves of brachiopods in several small slabs from 
 Assise E, 3 /. t^e Assise E. 3 /at Dugald brook and Indian brook. 
 
 (Gillis' branch). 
 
 
 Ori- 
 ented. 
 
 % 
 60 
 59 
 
 Re- 
 versed. 
 
 Ori. 
 
 ented. 
 
 Re- 
 versed. 
 
 Point 
 S.E. 
 
 Point 
 N.W. 
 
 Acrothele proles. 
 Leptobolus coUicia-collis. 
 
 % 
 20 
 15 
 
 3 
 23 
 
 1 
 6 
 
 1 
 8 
 
 " "2 " 
 
 
 26 
 
 7 
 
 9 
 
 2 
 
 A marine 
 current tra- 
 versed Indian 
 brook valley 
 in Cambrian 
 time. 
 
 Conditions of 
 entombment 
 of fossils in a 
 tidal estuary. 
 
 From the above observations and records it will be seen that there 
 was quite a decided orientation of the valves of the brachiopods in a 
 fixed direction in all the Etcheminian assises of Indian Brook valley, 
 wherever these Valves were in sufficient abundance to afford means of 
 determining their attitude. Had the orienting current influenced the 
 valves of only one or two horizons, or had these valves borne conflict- 
 ing testimony at difTerent levels, there might have been some question 
 as to the cause of the phenomenon, but in view of the constant orien- 
 tation here in a fixed direction thoughout Etcheminian time we can 
 only conclude that this valley is of pre-Cambrian origin, and guided 
 the course of a marine current that traversed it in a north-easterly 
 direction. 
 
 It is a question for consideration whether this current was an ordin- 
 ary shore current along the coast, or a tidal current. The following 
 are some conditions which bear upon the latter hypothesis. 
 
 It may be surmised that entombment in the mud of a tidal estuary 
 would take place chiefly on the ebb-tide. On the flood-tide the waters 
 coming from the open ocean would arrive free from sediment, but with 
 the waves beating on the freshly submerged shore, and the possible 
 contribution of river sediment coming into the head of the tidal estu- 
 ary, the returning water, retiring with the obb-tide, would carry a load 
 of sediment to spread over the sea-bottom and bury such animals as 
 had reached the limit of their vitality, or were unable to free them- 
 
61 
 
 selves from the muddy deposit settling from the turbid water as its 
 tidal flow abated. 
 
 Another reason why we might anticipate the burial of marine ani- Dying marine 
 mals on the ebb tide, is that those which had nearly reached the limit be buried on 
 of their life, would be revived when bathed in the fresh sea-current of *e ebb-tide.; 
 the flood-tide, coming to them charged with an abundance of food ; 
 whereas they would be more likely to succumb in the turbid returning 
 waters of the ebb-tide, which had been robbed of their nourishment 
 by other animals of the Benthos. Hence from these two causes, it is 
 probable the majority of the burials of marine animals in estuarine mud 
 will occur on ebb-tide, and we may look for the orientation of the 
 valves of animals that hung by a byssus or pedicle in the direction of 
 the ebb-tide. In fact this may be seen on any sandy shore where a few 
 stones serve to give a foothold for mussels. Another cause which 
 would help to the same result would be the undertow resulting from 
 the wave impulse from the ocean sweeping up into an open bay. The 
 translation of water near the surface resulting from the impulse of 
 these waves would have a complementary under-tow outward along 
 the bottom of the bay. 
 
 Supposing the burial of the Etcheminian organisms to have occurred 
 at the time of ebb in a hypothetical estuary, occupying the Cambrian 
 valley of Indian brook, the orientation of these organisms would im- 
 ply that the estuary opened to the north-east and that its head was to 
 the south-west, since the fossils are oriented to the north-east. But 
 suich a hypothesis is not supported by the actual condition of the 
 Etcheminian sediment. For if the mouth of the estuary were to the 
 north-east, it would be natural to look for a greater thickness of 
 deposits in that direction, but the reverse is the case ; for while on 
 the Gillis branch of Indian brook the thickness of the Etcheminian 
 terrane is considerably less than two hundred feet, on Dugald brook, 
 two and a half miles to the south-west, it is five hundred feet, and at 
 Boundary brook, two mjles further south-west, it is five hundred and 
 fifty feet. 
 
 These conditions iiaaply that the mouth of an estuary in Indian 
 Brooik valley, if such existed in Cambrian times, was to the south- 
 west and the ocieatatdon of the fosais shouJd have been in that 
 (direction, and not te tbe north-east, the actual direction. 
 
 We therefore turn to the marine current theory as the more jnro- A shore cur- 
 bable explanation of the orientation of the Etcheminian brachiopods ^obabfe^^^e 
 of this valley. To give passage to such a current, we must suppose of orientation, 
 that the neck which now connects Indian brook valley with that of 
 
62 
 
 MoLeod brook was proportionally lower in Etcheminian times than 
 now ; otherwise there would not be a sufficiently open passage for the 
 flow of the current from one basin to the other. 
 
 All along the Indian brook basin the Etcheminian sediments are 
 replete with material derived from the rooks of the complex pre-Camb- 
 rian along the sides of that valley and the Coldbrook volcanics with 
 which this was overlaid. The basin was bordered with a ridge of these 
 rocks all along its north-western side ; and from the exactness with 
 which the marine current was directed along this basin it seems clear 
 to me that there was a complementary pre-Cambrian ridge along the 
 south-eastern side of the basin as there is now on that side of the 
 valley. Both ridges were probably of greater elevation in Etcheminian 
 times than now. 
 
 In the course of the writer's observations in Cape Breton, no other 
 opportunity to test the orientation of the Cambrian brachiopod was 
 met with, except at Young point at the north-east end of the Bara- 
 chois basin, and the result here was surprisingly different from that 
 obtained on Indian brook. 
 
 Orientation of The fossils at Young point are supposed to belong to the lower part 
 LinguleUasat „ r>. . . „ /^ , . , - ^ ^. jf u^- j 
 
 Young point oi Division 2, a zone trom which no orientation data were obtained on 
 
 that?"ln*d°™ Indian brook. The fossils here are mostly Lingulellas of the species 
 brook. L. Sdwyni, and the tipper side of the layers (though the beds stand at 
 
 a rather high angle) was satisfactorily determined by finding from 
 eighty to ninety per cent of the shells with the hollow side up. This 
 peculiarity in the attitude of shells buried in the mud of the Cambrian 
 terranes is noticeable in many of the assises of the Cape Breton areas. 
 Two causes may have helped to produce it. Gravitation causing the 
 shell to sink to the bottom, would be best served by the shell present- 
 ing the side of least resistance, i.e., the rounded side to the bottom. 
 To this would be added the lifting power acting on the upper (inner) 
 surface of the valves, of the decomposition of the organic matter in the 
 fleshy parts of the body, producing a buoy, that would sustain the 
 shell with the inner side uppermost while sinking to the bottom. 
 
 The fossils described in the following table were found in a number 
 of seams of sandy shale in the lower part of the section and were in 
 a thickness of about a foot of this shale. The record of orientation 
 was made in reference to the cardinal points, and the shells of both the 
 upper and the under side of each slab were noted. 
 
63 
 
 'Orientation of Lingulellas in the sandy shale at Young point, Cape 
 Breton, from middle division of the Etcbeminian. 
 
 
 No. 
 
 of 
 
 Slab. 
 
 The umbo poists. 
 
 
 N. 
 
 S. 
 
 E. 
 
 W. 
 
 In this table the upper row of figures for each 
 slab denotes the number of valves on the upper 
 surface of the slab, the lower row those on the 
 lower surface. The prevalent current when 
 these shells were buried ran to the S.B., as 
 shown by the majority of the umbones pointed 
 to the N. and W. 
 
 1 f 
 
 2 ( 
 
 3 f 
 
 4 f 
 5/ 
 
 6 f 
 
 7 '■ 
 \ 
 
 7 
 28 
 
 7 
 11 
 24 
 12 
 
 6 
 
 7 
 10 
 17 
 10 
 
 
 15 
 10 
 
 3 
 
 12 
 
 8 
 
 8 
 
 21 
 
 12 
 
 5 
 
 3 
 
 2 
 
 6 
 
 6 
 
 
 
 8 
 
 11 
 
 3 
 
 8 
 
 5 
 
 12 
 
 14 
 
 15 
 
 5 
 
 5 
 
 13 
 5 
 2 
 1 
 5 
 5 
 
 2 
 26 
 10 
 
 7 
 35 
 17 
 
 8 
 
 7 
 12 
 17 
 
 5 
 
 3 
 21 
 
 1 
 
 
 164 
 
 105 
 
 98 
 
 171 
 
 Young point is situated at the north-eastern end of the Barachois Supposed to 
 Cambrian valley and therefore midway between the northern extremi- meeting of 
 ties of the two pre-Cambrian ridges that bounded this basin ; it might ^° *'""®° • 
 therefore be expected to give reliable indications of a current if any 
 prevailed in this valley at the time these fossils were entombed, but 
 the result was quite at variance with that obtained on Indian brook, 
 as may be seen by studying the preceding table. 
 
 The observations of the orientation of these shells were referred to 
 the cardinal point. If this be changed to correspond to the columns 
 used to show the orientation in the Indian Brook basin, we find an 
 average of valves pointing S.W. 138, N.E. 131, S.E. 102, N.W. 167. 
 The orientation, therefore, was not to the north-east, as in Indian 
 brook valley,but to the south-east, indicating that the current ran 
 -chiefly in this direction. But only 32 above normal are oriented in 
 that direction, or only 77 per cent more than one quarter of the valves. 
 
 A study of the table will show how exceedingly variable the courses Orientation at 
 tire. This extreme variability would be explained by the existence extremely 
 here in Lower Etcheminian time of an eddy between two conflicting variable. 
 -currents, one coming out of the Barachois basin, and another more 
 powerful passing eastward across the end of the pre-Cambrian ridges 
 that bounded that basin. Such a current may well have existed, for 
 at present there are no pre-Cambrian rocks visible for a long way to 
 -the north of Barachois basin, the space in front being occupied by a 
 wide extent of Lower Carboniferous and Carboniferous deposits. 
 
64 
 
 CONDITION OF THE SEDIMENTS. 
 
 Similarity In Cape Breton the Cambriaa rocks have much the same litho- 
 
 sedimentetn logical appearance as they have in southern New Brunswick, and they 
 
 Cape Breton ^j.^ hardened to about the same degree ; and do not, any more than 
 and other a ' i • i j j 
 
 parts of Nova the latter, exhibit areas of metamorphic rocks, except the includea 
 
 > ootia. islands and ridges of pre-Cambrian age. There are no intrusions of 
 
 granite or other hypogene rocks, nor are there crystalline schists such 
 
 as are met with in the areas referred to the Cambrian system in the 
 
 mainland of Nova Scotia. 
 
 The process of hardening is most marked in the sandstones, which, 
 
 when in heavy bed=!, are converted into pseudo-quartzites ; yet we 
 
 never meet with a true quartzite in which the grains or particles of 
 
 sand are invisible from the filling of the interstices between the 
 
 Lime and iron grains with silica. While the cement is to a great extent silicious, 
 
 smoarammon showing that the sandstones have been steeped in heated waters, yet 
 
 cements of the the strata often respond to the test for calcium-carbonate, an evidence^ 
 
 Cambrian ^ 
 
 rooks in Cape that the cement IS in part calcareous. 
 
 Breton. 
 
 In the flags of the Johannian division of the St. John terrane, which 
 
 split readily along mud-seams, or mica-besprinkled layers, there are 
 often numerous cross-joints filled with calcium-carbonate. When 
 weathered, these flags fall to pieces at the joints, and the surface of 
 the soil where they prevail, abound with angular sandstone fragments. 
 The corresponding middle portion of the Etcheminian terrane, which 
 is also quite arenaceous, carries a cement largely composed of car- 
 bonate or peroxide of iron ; the latter is often sufficiently abundant to 
 give a strong colour to these sandstones, or even at times to concen- 
 trate to irregular thin beds of red hematite. The strength of th& 
 cement which holds together the particles of the rocks of the middle- 
 members of the Etcheminian and St. John terranes respectively cause 
 these members to stand out prominently, and they are consequently 
 visible in raised ridges when other parts of their respective terranes 
 are concealed from view by deposits of drift. They are therefore 
 useful in revealing the structure of the Cambrian terranes, which 
 otherwise would be difficult to unravel. 
 
 Causes of The prominence of the middle member (Johammian) of the St. John 
 
 prominence, gpoup^ jg tifae more maii^ied because it ia bordered both above and 
 
 below by soitt roeks. These so£ter ueiiiidbera, origiirtally modrbeds, are 
 
 asnailly in the coodition of slates ; o£teci they aite so dett ma to> baxe 
 
 no visible bedding' pl«nes. In aJI this region tlike dea.'Tiage planes hme 
 
65 
 
 a general course of S.W. to N.E. and a sceep hade, and where the dip 
 of the bed is at an angle with the course, or the beds are flat, the 
 fossils they contain are more or less distorted and often are quite un- 
 recognizable. 
 
 There are two areas, however, which have not been so much affected 
 by this cause of effacement of fossils, namely the valleys of McLeod 
 and Indian brooks. A third, the Mira valley, also has fossils in good 
 condition, especially when preserved in limestone layers. 
 
 Although there is considerable lime diffused as a cement through 
 the Cambrian terranes, heavy masses of limestone are unknown in 
 them. But a few thin limestone beds are found in the upper division 
 (Bretonian) of the St. John terrane. This is in contrast with the 
 rocks of the pre-Cambrian complex, which possesses large bodies of 
 gray limestone, and with the overlying Lower Carboniferous terrane, 
 in which also considerable limestone masses and gypsum beds are 
 found. 
 
 Some difference in condition may be noted between the s'ates of the Slates of the 
 Etcheminian and those of the Coldbrook terrane. The latter have terrane dis- 
 suffered more from sliding movements so that the fossils in these slates than th^e'^^ 
 have been much obscured ; it is only where they have been imbedded of the 
 in phosphatic nodules that the form 5 of the fossils have been preserved. 
 But this can hardly be regarded as a proof that the terrane in which 
 they are badly preserved has been subjected to greater metamorphism 
 than the one in which the fossils are in better condition, for in the Cold- 
 brook terrane these fossils are contained in a bed of slates only thirty 
 feet thick, while the rest of the terrane consists of conglomerates, 
 agglomerates and other trap- rocks, which would have resisted dynamical 
 movements more energetically, and the slates would have suffered 
 proportionately the more. 
 
 The small amount of alteration which has affected the Cambrian Cambrian of 
 ,,.-,. , ,1 1 Cape Breton 
 
 strata in Cape Breton, would indicate that they have never been very deeply buried. 
 
 deeply buried. The whole thickness of the three terranes was not 
 sufficient to bring the lower beds within the influence of the heat 
 of the earth's interior; and they could not at any time since their 
 formation have been deeply buried beneath more recent terranes. 
 And even the Lower Carboniferous may not have covered them every- 
 where,- for Mr. Fletcher in several places represents the Cambrian as 
 covered directly by the millstone grit. 
 
 The action of pressure from the direction of the Atlantic ocean is 
 everywhere traceable in the Cambrian terranes, and quite corresponds 
 
 5 — c. B. 
 
66 
 
 to conditions observable in the Cambrian areas of southern New Bruns- 
 
 Strata ar- wick. In the Barachois basin, though the succession of members of 
 ranged trans- . . ,. i ^ i i i 
 
 verse to a ihe terranes is in ascending order trom the north-east to the south- 
 
 DresBure^from ^^st, the cleavage planes are at right angles to this and so parallel to 
 
 the S.E. the direction of the pressure referred to. 
 
 So also in Indian brook basin, for the greater part of its length the 
 Cambrian 'terranes are arranged in a single succession transverse to 
 the valley, having been folded parallel to the valley and tranVerse to 
 the crowding pressure from the south-east. The Cambrian rocks of 
 this valley, for the greater part of its length, display simply the north- 
 east slope of a synclinal fold, of which the opposite slope has been 
 uplifted and entirely removed by erosion in the long ages that have 
 passed since Cambrian time. The pre- Cambrian platform on which 
 this part of the fold rested, now stands up as a high ridge on the south 
 east side of the valley, cutting it off from connection with the Cambrian 
 basins along the shore of East bay. 
 
 Again, in the valley of the Mira river, overturned dips are prevalent 
 along its south-eastern side, especially in the Etcheminian terrane, as 
 may be seen on examination of Mr. Fletcher's map of that district. 
 The whole series of the older Palaeozoic terranes along the north west 
 side of the Mira valley also, are seen to dip seaward without over- 
 turned dips, and in the middle of the valley the anticlinal and synclinal 
 folds are in a general way parallel to the Cambrian basins further to 
 the north-west, so that the parallelism of structure of the ridges and 
 valleys existing in pre-Cambrian times, along this coast, continued to 
 be emphasized by a continuance of the pressure in the post-Cambrian 
 ages. 
 
PART II 
 
 PALEONTOLOGY. 
 
 In consequence of the finding of trilobites, Brachiopods, etc., and of 
 Cambrian genera in the Etcheminian strata, and for reasons given below, 
 the writer proposes to revert to the classification of 1889, wherein these 
 deposits are called the Basal Series (of the Cambrian System).* 
 
 It has been found that slates with fossils of Cambrian genera are 'Volcanic 
 
 "111*!" roPKfl sij't fcrift 
 
 included in the important group of volciinic rocks which lie at the base of the 
 base of the Etcheminian, and that where the dip of the volcanics can be C'*™brian. 
 found, as is not infrequently the case, it agrees with that of the Etche- 
 minian. It is thought therefore that those volcanica (the Coldbrook 
 group) should be included in the Basal Cambrian. 
 
 Both in New Brunswick and in Cape Breton the Coldbrook group 
 begins with lavas showing deposition free of pressure, as they are amyg- 
 daloidal ; or with agglomerates devoid of evidence of marked aqueous 
 wear. The deposition therefore did not begin in deep water, or on 
 exposed sea coasts, or under heavy pressure. The foundation upon which 
 the volcanics rest shows in several places marks of deep sub-aerial decay 
 at the line of contact. Calcareous bands are dissolved, leaving the 
 silicious portion of the strata. The feldspar of the granitic rocks is Worn condi- 
 kaolinized, and the magnesian silicates are hydrated, impure graphite *r'e"cambrian 
 beds are changed to a black amorphous crumbling shale, and a depression sediments. 
 or narrow valley is usually found at the contact of the two terranes. 
 These conditions appear to indicate that the pre-Cambrian complex had 
 long been above the sea-level in these districts when the first Cambrian 
 eflfusives were thrown out upon it. 
 
 Another point worthy of note in this connection is the large amount 
 of feldspathic material in the Etcheminian beds ; the very sands are often 
 composed of feldspathic grains, and these largely of non-kaolinized feldspar, 
 as though they had not been exposed to sub-aerial decay. Feldspar in 
 this condition is found in two kinds of deposits, those that are the result 
 
 * Trans. Roy. Soc. Can., vol, vii, Sec. iv. p. 135. 
 5J — C. R. 
 
68 
 
 of glacial wear and those found around volcanic vents, where particles of 
 rock have been torn from the walls and blown out upon the surface of 
 the earth. These if dropped into the sea would soon be covered up by 
 fine mud and preserved in their original crystalline condition. The Etche- 
 minian appears to represent largely the submarine condition of such efi"usive 
 rocks. On the other hand, the Coldbrook series, as has been intimated above, 
 represents the preceding sub-aerial phase of the eruptives. It is true that 
 we find in many places conglomerates at the contact of these two series 
 of rocks, thus diverse in appearance ; but elsewhere there are no beds of 
 rolled fragments at the contact, and the passage is direct from ash-beds 
 or diabases, to the slates and sandstones. In reports of the Canadian 
 Geological Survey of 1870-71, pp. 57-59, etc., relating to the province of 
 New Brunswick, both these groups of rocks have been included in the 
 Huronian system. They may be equivalent in age to the upper part of 
 that series, but unfortunately the absence of fossils in the original 
 Huronian leaves this matter in doubt. 
 
 Pre-Cambrian As we contemplate the physical conditions of the initial epochs of 
 Maritime Cambrian time in the Maritime Provinces, we seem to see a region long 
 Provinces elevated above the sea, now subjected to depression nearly to the sea 
 level, the depression being accompanied with extrusion of lavas and 
 volcanic mud and the ejection of stones and ashes. These at first were 
 cast upon a land surface, but, as the crust of the earth continued to sink, 
 it was covered by the sounds and bays of a shallow sea, diversified with 
 pre-Cambrian ridges and islands, of greater or less extent. 
 
 For the above reasons, as well as because the stratified rocks of the 
 underlying complex are markedly unconformable to the Cambrian, the 
 volcanics are thought to belong to the latter, and to give the natural base 
 of this system. 
 
 The accompanying table will then show the classification of the Cam- 
 brian system, as seen in the Maritime Provinces of Canada. 
 
 (See accompanying sheet.) 
 
69 
 Base of the Palaeozoic Rooks in the Maritime Provinces of Canada. 
 
 Groups, and kind of 
 
 Rocks in Cape 
 
 Breton. 
 
 Dark gray, and black car- 
 bonaceous shales often 
 changed to slates ; a few 
 thin seams and lentiles 
 of dark limestone, and 
 some thin flags. 
 
 2. Micaceous gray slates, 
 flagstones and quartzi 
 tes. Iron bearing in 
 Mira Valley, Cape Bre- 
 ton. 
 
 Dark gray slates or shales 
 with calcareous lentiles. 
 Gray sandstones. In- 
 terraned conglomerates 
 at and near the base. 
 
 3. Fine greenish-gray argil- 
 lites, some reddish-gray. 
 Horizon of rooting sla- 
 tes, in 0. Breton and 
 Newfoundland. 
 
 Red sandstone and red 
 and gray argillite. Low- 
 er iron-bearing horizon 
 of Cape Breton Cam- 
 brian. 
 
 1. Gray shale or slate with 
 some quartzite and con- 
 glomerate, the latter 
 especially at the base. 
 
 Co. Dolorites, breccias and 
 amygdaloidal ash rocks. 
 Some gray shales about 
 the middle. 
 
 •- p. 
 
 rt 
 
 o 
 
 
 3 
 
 m 
 
 W 
 
 w 
 
 0) o 
 
 ^' 
 
 Leading Genera of the Several 
 Groups. 
 
 e. Harpes, Trinucleus, in N. W. 
 New wick. 
 
 d. Oyclognathus, ParabolineUa, 
 Tetragraptus, Didymograp- 
 tus, in S. New Brunswick. 
 
 e^. Asaphellus, ParabolineUa, 
 Triarthrus, Bellerophon. 
 
 c. Dictyonema, Monobolina, Schi 
 
 zambon, Acrotreta. 
 6. Peltura, Sphserophthalmus, 
 
 Leptoplastus, Ctenopyge. 
 a. Pardbolina, Agnostus, Ano- 
 
 mocare, Orthis, in S. New 
 
 Brunswick. 
 
 
 hJ-o 
 
 be 
 
 ■g 
 
 K. Agnostus, Lingulella. 
 (Place of Olemis). 
 
 6. Paradoxides, Beyrichia, Lin- 
 
 gulepis. 
 a. Obolus, Lingulella, Lingulepis. 
 d e. Paradoxides, Solenopleura, 
 
 Ptychoparia, Miorodiscus. 
 c. Paradoxides, Conocoryphe, 
 
 Liostracus, Agnostus. 
 a-b. Protolenus, Bllipaocephalus, 
 
 Beyrichona, Trematobolus, in 
 
 S. New Brunswick. 
 
 fH g 
 
 Succession of 
 the Cambrian 
 faunas in the 
 Maritime 
 Provinces and 
 the rocks that 
 concern them. 
 
 Solenopleura ? Ostraooda, 4 
 
 genera. 
 Acrothele, Lingulella, Obo 
 lus Acrothyra, Hyolithes. 
 
 Holasaphus, Paradoxidoid 
 trilobite, Ostracoda, Bil- 
 lingsella, Lingulella, 
 Acrothyra, Obolus, 
 Hyolithes. 
 
 Lingulepis, Lept obolus, 
 Obolus, Lingulella, Acro- 
 thyra, Acrotreta, Hyoli- 
 thes. 
 
 OS 
 
 43 
 
 Obolus, Lingulella, Linguledsis, 
 Acrothyra, Acrotreta, Lepto- 
 bolus. 
 
 2 Ostracoda. 
 
 
70 
 
 The Tremadoo 
 
 Fauna 
 
 discovered. 
 
 The "Upper 
 Paradoxidea " 
 Pauna of 
 Sweden 
 discovered. 
 
 The 
 
 Holasaphus 
 
 fauna. 
 
 In this table we have been able to present one of the faunas of the 
 European Cambrian, heretofore unrecognized in Eastern Canada, i. e., 
 the Tremadoc fauna of English writers, the Ceratopyge fauna of the 
 Swedes (the Euloma-Niobe fauna of Prof. W. C. Brogger), the Dicello- 
 cephalus fauna of the Mississipi valley. This is based on the discovery of 
 examples of Asaphellus, Parabolinella and Triarthrus in soft shale on the 
 upper part of McLeod brook, in Boisdale district. It happens that at St. 
 John, New Brunswick, the strata which would carry this fauna is in the 
 channel of the river in the upper part of the harbor of St. John, with the 
 Dictyonema fauna on one shore, and the^Tetragraptus fauna on the other, 
 hence it has not been recognized in the St. John Basin. 
 
 Also, the strata of Division 2 of the St. John group, the Johannian 
 division, which we have all along spoken of as the probable place of the 
 Olenus, it would seem will have to be assigned largely to the Paradoxides 
 zone, since Mr. S. Ward Loper, who has been collecting in Cape Breton 
 for the TJ. S. Geological Survey, has found a Paradoxides, which the 
 writer would regard as a variety of P. Forchhammeri, in the middle of this 
 Division. From this it may be inferred that the two lower bands {a and 
 h) of this division may be assigned to the upper part of the Paradoxides 
 zone. I had found in the Mira river Cambrian a cheek of Paradoxides 
 type in this division, but this alone was not sufficient to determine the 
 presence of this genus in the Johannian division. 
 
 Another important point made during the past season was, that the 
 strata at Youngs point (or McFees point), from which the fossils came, 
 collected by Messrs. Weston and Robert many years ago for the Canadian 
 Geological Survey, and which the author had described, and referred (on 
 account of their resemblance to European forms) to the Ordovician fauna, 
 are in the Etchemiiiian or basal Cambrian. The more abundant material 
 gathered since Messrs. Weston and Robert's visit, show that the species 
 referred by me to Orthisina is a Billingsella. The Holasaphus does not 
 agree with any other basal Cambrian trilobite so far described ; but the 
 Hyolithes may be a form of H. americanus of Billings. 
 
 The exploration in Cape Breton has added greatly to our knowledge of 
 the Etcheminian Faunas. In New Brunswick we had already recognized 
 two lithological divisions in the Etcheminian rocks, of which the lower was 
 bare of any but the lowest forms of life, and worm trails ; but some 
 forms of higher types were found at the base of the upper division — 
 Obolus, Hyolithes, Orthotheoa. 
 
 In Cape Breton fossils occur at numerous levels throughout the Etche- 
 minian rocks, and even in the Coldbrook volcanics there is a fauna. And 
 
ri 
 
 it would appear that three important faunal changes can be traced in the 
 fossils of this Basal part of the Cambrian system. 
 
 A conspectus of the several fossiliferous zones of the Etcheminian and Cold- 
 brook terranes of the Basal Cambrian in Cape Breton, vnth list of the 
 species which occur. 
 
 In making this tabulation of the species and varieties of fossils in these 
 old Cambrian rocks it is necessary to use names in anticipation of the 
 descriptions further on in this report. Many of the species have already 
 been published in the Proceedings of the Royal Society of Canada, in the 
 Bulletin of the Natural History Society of New Brunswick (St. John, 
 N.B,), and in the Canadian Record of Science ; but the descriptions are 
 reproduced here as they have not appeared in any official report, and 
 because there is additional information to present with a number of the 
 species. 
 
 The assises or zones are taken in their order from the oldest upward. 
 
 COLDBROOK TERRANE, assise " co." 
 
 This is the only assise in which fossils have been found, in this terrane. 
 It consists of a body of gray shales about thirty feet thick, lying near the 
 middle of the terrane. The layer in which the' fossils were found in chief Fossiliferous 
 abundance was a bed of compacted, slicken-sided shaie, from a pure gray Coldbrook 
 to a lavender gray in colour, and having a few grains of feldspar sand, volcanic 
 and scattered grains and pieces of calcium phosphate. The rock is harder 
 than the shales resembling it in the Etchminian terrane above, though it 
 is not any more silicious or sandy, and it lies between masses of volcanic 
 rock, chiefly ash beds and felsites. The presence of these shales in the 
 midst of the volcanics indicates a temporary cessation of volcanic activity^ 
 and that the deposition of the fossiliferous bed occurred in comparatively 
 clear water is shown by the grains and lumps of calcium phosphate, with 
 which it is charged. 
 
 Though thus peacefully interred, the valves of the Brachiopods were 
 afterward subjected to disturbing agencies by which they were twisted 
 and distorted, so that for many of the valves, the species, and even the 
 genera are unrecognizable. Hence it comes that the numbers given in 
 the list below do not by any means show the abundance of the fossils, as 
 many were not worth preserving. When the fossils happened to be 
 buried in calcium phosphate or filled with this mineral, the form was 
 preserved and it is mostly these that are listed. The smallness and the 
 
72 
 
 roundness of many of the grains of calcium phosphate would lead one to 
 suspect the presence of Foramenifera, but I was unable to observe the 
 smooth pitted surface by which the Foramenifera of the Protolemus beds 
 may be recognized. 
 
 Species of Hyolithes, small, tubes 3 
 
 Acrothyra signata-prima ventral 18, dorsal 16 
 
 Acrotreta papillata-prima " 1 " 
 
 Leptobolus torrentis " 1 " 
 
 Lingulepis pumila " 3 " 4 
 
 Lingulella cf. longovalis " 1 " 1 
 
 Obolus torrentis " 1 " 1 
 
 Indiana ovalisprima carapace 1 right v. 1 
 
 EscasoDa 1 1 ingens ? left v. 1 
 
 Notwithstanding that all these genera are Etcheminian, and that we 
 can no longer separate the Coldbrook volcanic rocks as pre-Cambrian, 
 there appears to liave been an advance or growth in the species as they 
 pass upward to the next terrane. This will appear as regards their 
 size if they be compared with the most nearly related Etcheminian forms. 
 
 mm. mm. 
 
 Their Acrothyra signata prima. .. 2x2^ A. signata 2x3 
 
 minutenesT Acrotreta papillata-prima. . 2x2^ A papillata 2^x2^-3 
 
 Leptobolus torrentis 3x2 L. atavus 5x3|^ 
 
 Lingulepis pumila 6x4J L. longinervis 11x8 
 
 Lingulella cf. longoval-is. . . . 7^x5 L. longovalis 9x6 
 
 Obolus torrentis 6x6 O. triparilis 9x8 
 
 Indiana ovalis-prima 5 Jx3| I. ovalis 4Jx3J 
 
 Escasona ? 1 ingens 6x6 J ? 
 
 The fossils of the first column are of the Coldbrook terrane, those of 
 the second, Etcheminian. 
 
 Throughout the inarticulate Brachiopoda represented here, there 
 appears to have been an average increase of nearly fifty per cent, both in 
 the length and breadth of the valves in the resembling forms of the 
 Etcheminian (Lower) fauna. There seems not to have been a dwarfing 
 of the species of this assise from incongenial habitat, as its fine shales 
 should rather have shown larger species. In the Etcheminian terrane the 
 advent of shaly beds was accompanied by the appearance of large species, 
 as for example the two typically largest species of the two Etcheminian 
 faunas, Lingulepis Gregwa (Assise E. 1 d.) of the Lower fauna and 
 Obolus Bretonensis (Assise E. 3d.) of the Upper. 
 
73 
 
 DESCRIPTION OF THE FOSSILS OP THE COLDBROOK 
 TERRAJSTE. 
 
 ACROTHYRA SIGNATA-PRIMA. Plate I, figS. 1 CU-g, 
 
 Test (calcareo-)corneous ; valves tumid. _ Ventral valve variable in Acrothyra 
 form, longer than broad, often quite tumid, with the posterior half prima, 
 straighter than the anterior, which in some examples is strongly arched 
 down toward the margin. Hinge area variable in height, beak sometimes 
 overhanging the hinge, sometimes withdrawn from the perpendicular. 
 Interior — There is a visceral callus from one-quarter to one-third of the 
 length of the valve, wider in front than behind, bordered by vascular 
 grooves ; the central depression is greater toward the apex than toward 
 the front. Outside of the aforesaid grooves is another and a shorter pair, 
 more widely diverging ; traces of the lateral muscle scars are seen outside 
 of this latter pair of grooves. 
 
 The dorsal valve is more regular in form than the ventral, but also 
 often quite tumid. The umbo is low and close to the margin. Interior 
 — This possesses a shallow median septum extending to the middle of the 
 valve ; on each side of the septum, at the hinge line, are pits for the car- 
 dinal muscle. A pair of diverging grooves in the posterior half of the 
 valve mark the position of the lateral muscles. Both valves have thick- 
 ened borders and are flattened inside along the lateral margins. Consid- 
 ering the variableness of this form, one might be disposed to think 
 it a mutation of A. signata, and it is so classed here ; but the following 
 differences are apparent : The visceral callus of the ventral valve is 
 broader and not so distinctly impressed, and the grooves at the posterior 
 end project farther backward. In A. signata the callus does not have 
 the strong bounding ridges that this frequently is seen to have. The 
 cardinal area in this form never has the extreme over-hang that marks A. 
 signata, and the back part of the ventral valve is not produced. 
 
 Sculpture. — The surface is smooth, but a strong lens reveals fine con- 
 centric ridges at intervals on the surface of the shell. 
 
 ^i2;e._yentral, length, 2J mm. ; width, 2J mm.; depth, \\ mm. Dor- 
 sal, length and width, 2^ mm. ; depth, | mm. 
 
 Horizon and locality, — Fine gray shales in the volcanic beds of the 
 Coldbrook Group at Dugald Brook, Escasonie (C.B.), N. S. 
 
 ACEOTRETA PAPILLATA-PRIMA, n. mut. PI. Ill, figS. 1 a-C. 
 
 Only the ventral valve of this form is known. This is wider than long, Acrothyra 
 tumid, with the cardinal area vertical. Interior.— In this the visceral ^X^a***" 
 
74 
 
 callus is of a circular form, and only one-quarter of the length of the 
 valves. Its ridge closely encircles a deep pit, which lies just in front of 
 the foraminal opening, in the direction of which it becomes narrower and 
 shallower. The traces of a pair of straight diverging grooves are discern- 
 able at the sides of the callus. 
 
 Sculpture. — This consists of minute concentric ridges, visible only with 
 a strong lens. 
 
 (Size.— Length, 2 mm.; breadth, 2^ mm.; depth, 1 mm. 
 
 Horizon and locality. — Fine gray shales in the volcanic beds at Dugald 
 Brook, Escasonie (C.B.), N. S. Scarce. 
 
 The short callus distinguishes this species from Acrothyra signata-prima 
 with wliich it occurs. The pit in this callus, though so short, is analog- 
 ous to that of A. signata, so that in this earliest fauna these two types of 
 umbonal muscle scar and groove of the Acrotretinae were already differ- 
 entiated. 
 
 Leptobolus toreentis, n. sp. Pl. vi, fig. 1. 
 
 Iieptobolus Shell thin, surface shininsr. Form elongate-oval, 
 
 torrentis. 
 
 Ventral valve, obtusely pointed at the back somewhat acutely rounded 
 
 in front ; elevated along the middle ; somewhat flattened along the sides 
 
 within the margin. 
 
 Interior. — By decortication a low boss and a transverse furrow behind 
 it are exposed on the mould, about three quarters of the length of the 
 valve from the hinge ; if this boss marks the front of the callus, the 
 central muscles are unusually far forward, more advanced even than in 
 L. atavus of the Etcheminian terrane. There are faint impressions of the 
 lateral septa on the sides of the valve. 
 
 Dorsal valve unknown. 
 
 Sculpture. — The surface of the shell is covered with minute, low tuber- 
 cles, cancellate in arrangement ; through these can be traced faint parallel 
 lines, concentric to the umbo. Along the median third in places can be 
 seen about six broad flat ridges, radiating from the direction of the umbo ; 
 these break the continuity of the concentric ridges. 
 
 Size. — Length, 3mm ; width, 2 mm ; depth, ^mm. 
 
 Horizon and locality. — Gray shales in the volcanic rocks of the Cold- 
 brook terrane. Scarce. 
 
75 
 
 This littlo species is only known from a ventral valve. It is even 
 smaller than L. atavus of the Etcheminian terrane and is flatter along 
 the sides. 
 
 LlKQULEPIS PUMILA, N. SP. Pl. VII, FIGS. 5a AND b. 
 
 Shell thick and long-ovate. Lingulepis 
 
 pumila. 
 
 Ventral valve somewhat ridged toward the beak, which is much pro- 
 longed. 
 
 Interior. — The imprint of the foraminal groove on a mould of the valve 
 extends one third of the length of the valve, and a faint imprint of the 
 callus one-half the length or more. The dorsal is ovate with an obtuse 
 back and straightened sides. At the front half of the valve are several 
 strong concentric ridges, about seven in the space of a millimetre ; behind 
 these are others, more faintly marked. Interior. — A small exfoliated 
 valve show-i a median sulcus and faint print of muscle scars about the 
 middle of the valve. 
 
 Sculpture. — This consist of irregular concentric ridges, about six in the 
 space of a millimetre, near the back the concentric ridges are much more 
 minute. 
 
 Size. — Length of the ventral valve 6 mm.; width, 4^ mm.; depth, 1 mm. 
 
 The dorsal is about 1|- mm., shorter than the ventral. 
 
 Horizon and locality. — Gray shales of the Coidbrook terrane at Dugald 
 Brook, Escasonie. 
 
 LiNGULELLA cf. LONGOVALIS. Plate VII, lig. 2. 
 
 A single example of a thin shelled Lingulella of the form and size of Liugulella cf. 
 the above named species of the Lower Etcheminian Fauna was found. 
 The outline has been preserved by a filling of calcium phosphate. The 
 margin is somewhat acutely rounded in front, and the sides, somewhat 
 flattened, are evenly curved from near the hinge. The valve has two or 
 three strong growth grooves. 
 
 Sculpture. — This consists of fine irregular wavy ridges, made visible by 
 the lens ; there are about 6 ridges in the space of a millimetre. The 
 ridges are irregularly granulated along the crest, the granulations being 
 obscurely arranged in rows diverging from the apex ; on the lateral slopes 
 for a short distance, these low tubercles form more distinct curved ridges 
 radiating from the direction of the umbo. 
 
 Size. — Length 7| (?) mm. ; width 5 mm. 
 
' Obolua 
 torrentis. 
 
 76 
 
 Horizon and locality. — Same as the preceeding. 
 
 This species has a smoother surface than L. longovalis of the Etche- 
 miaian (Lower) Fauna, but otherwise much resembles it. 
 
 Obolus torrentis, n. sp. PI. VIII, fig. 1. 
 
 A few examples of shells were found which from their form should 
 apparently be referred to the above genus. 
 
 The Valves are broadly orbicular and moderately arched. 
 
 Ventral. Only an interior of a broken valve could be identified. It 
 shows a thickening of the margin toward the hinges. Interior. — The 
 cardinal area is laterally extended and is striated ; the pedicle furrow is 
 distinct and depressed. 
 
 Dorsal. An undersized exfoliated example was found, which is dis- 
 torted by compression longitudinally, and shows traces of concentric 
 ridges. There is a well-defined median sulcus on the mould extending 
 forward from near the hinge. 
 
 Sculpture. — Unknown, except as above noted. 
 
 Size. — Length of dorsal 5J mm. (probably shortened by pressure) ; 
 width 6 mm. A rim of an Obolus from the same terrane is 8 mm. across. 
 
 This species is near the size of 0. triparilis of the Etcheminian Lower 
 Eauna, but is thinner, has a more obtuse beak to the ventral valve, and a 
 weaker hinge area to the dorsal valve. 
 
 OSTRACODA. 
 
 Ostracoda. We have as yet only two forms that can be referred to this group of 
 
 crustaceans, one a very peculiar one, the other similar to oval carapaces 
 that are found in the beds of the overlying terrane. These will be found 
 described in connection with other ostracoda of the Etcheminian terrane. 
 
 ETCHEMINIAN TERRANE. 
 
 Assise E. la. 
 
 Assise holding This assise rests upon the effusive rocks of that last described. The 
 
 Etohemiii! lower part is a red amygdaloid that graduates upward into a red clay-slate, 
 
 Fauna. which in its turn is covered by a bed of trap. The fossils are scarce and 
 
 are found in the slate. A large Hyolithes occurs here, an Orthotheca and 
 
 worm burrows, also a large Brachiopod. The fossils are badly preserved. 
 
77 
 
 Assise E 16. 
 
 The rock in which the fossils are contained is a greenish-gray sandy 
 layer in lavender gray, rusty weathering, fine shale. The grains of the 
 sandy layers are mostly of pellucid quartz and green quartz (some of a 
 bright copper green). There are numerous minute fragments of red 
 feldspar not kaolinized, (and some of red felsite). There is a pale green 
 (magnesiau) deposit in places among the sand grains. The sand is mixed 
 with numerous fragments of the shells of Brachiopods and a few of Ostra- 
 cods. The fossils found here were : — • 
 
 Fossils — 
 
 Acrothyra signata ventrals 7, dorsals 
 
 Leptobolus ? , ' " 1 " 
 
 Lingulepis Gregwa ? (mould) ... " 1 " 
 
 LinguleUa longovalis " 2 " 
 
 Obolus triparilis " 3 " 
 
 Bradorona spectator-acuta . . , . right v. 2 left v. 
 
 B observator-lsevis . " 2 " 
 
 Bradoria vigilans-obesa " 1 " 
 
 Assise E \c. 
 
 The rock here is also a fine gray to lavender gray shale, weathering 
 pale brown in the cracks. The following species occur : — 
 
 Acrothyra signata-sera ventrals 59, dorsals 53 Fossils of 
 
 '' , „ ,. , assise E Ic. 
 
 A tarda " 6 " 4 
 
 LinguleUa longovalis " 1 " 
 
 Lingulepis Gregwa , " " 5 
 
 Eoobolus triparilis " " 7 
 
 Hyolithes sp. (wide apertural 
 
 angle) tubes " 2 
 
 Orthotheca sp " " 2 
 
 Bradorona perspicator-maxima. . right v. 1 left v. 
 
 B spectator " 1 " 
 
 Bradoria ornata " 1 " 
 
 B vigilans, mut " 1 " 1 
 
 Crustacean, part of a carapace 
 
 with strongly pitted surface 
 
 (part of cheek of trilobite ?) " 1 
 
 4 
 1 
 
 Fossils of 
 assise E V>. 
 
 
 
 
 1 
 
 
 4 
 
 
 
 
 
 2 
 
 
 1 
 
 
78 
 
 Assise E. Id. 
 
 Fossils of E Id 
 at Dugald 
 brook. 
 
 The fossiliferous layers in this assise consist of gray and brownish gray 
 shale, somewhat charged with fine sand, the sand grains being largely 
 feldspathic particles. The rock was open in grain, and there are grains of 
 a soft, grass green mineral, and of kaolinized feldspar (Gregwa shale). 
 The species are as follows : — 
 
 Acrothyra signata-tarda ventrals 24, dorsals 27 
 
 Acrotreta papillata " 2 " 1 
 
 Lingulepis Gregwa " 42 "38 
 
 var. robusta. " 5 " 1 
 
 Orthotheca tube " 2 
 
 Bradorona spectator ": . right v. left v. 2 
 
 B acuta " 2 " 
 
 At Boundary brook in the Indian brook vralley, some miles S.W. of 
 Dugald brook there is some variation in the strata of this assise and a 
 fuller fauna. The rock is a dark brownish gray feldspathic sandstone, 
 full of small gray or pink grains of feldspar, and of darker feldspathic and 
 quartzose grains ; fragments of dark gray felsite occur half an inch in 
 diameter and less. The rock is not strongly cemented and is traversed by 
 calcareous veins. Tiie surfaces of the fossils are much corroded, and fre- 
 quently only a thin film represents the fossil. The following occur here. 
 
 Fossils of E Id 
 at Boundary 
 brook. 
 
 Acrotreta papillata ventrals 25, dorsals 24 
 
 A lata 
 
 Leptobolus atavug, mut. tritavus. 
 
 L cf coUicia 
 
 Lingulepis Gregwa 
 
 L ■ sp 
 
 Obolus sp " 
 
 Orthotheca sp. (broken) tube. , . " 
 
 Bradorona perspicator right v; 
 
 B spectator " 
 
 B observator " 
 
 B benepunota. " 
 
 Bradoria vigilans, mut " 
 
 Escasona rutellum-prima " 
 
 Schmidtella(?)pervetus-concinna. " 
 
 2 ' 
 
 
 
 5 ' 
 
 3 
 
 3 • 
 
 1 
 
 40 
 
 44 
 
 5 ' 
 
 3 
 
 2 
 
 
 
 ( 
 
 2 
 
 2 left 
 
 . V. 2 
 
 5 ' 
 
 9 
 
 4 ' 
 
 8 
 
 3 ' 
 
 2 
 
 1 ' 
 
 
 
 ' 
 
 1 
 
 ' 
 
 1 
 
1, 
 
 dorsalE 
 
 2 
 
 Fossils of 
 assise E le 
 
 2 
 
 
 1 
 
 
 14 
 
 
 8 
 
 
 1 
 
 
 4 
 
 
 1 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 
 1 
 
 
 1 
 
 left V. 
 
 1 
 
 
 1 
 
 (( 
 
 1 
 
 
 79 
 
 Assise E, le. 
 
 The fossiliferous seams here consist of greenish gray sand, alternating 
 with others that are lavender gray. The sand consists largely of grains of 
 pellucid quartz ; there are pale green particles and films which may be 
 glauconite or some magnesian silicate. There are also black grains and 
 a few lumps of calcium phosphate. Some of the fossils are fragmentary. 
 
 Leptobolus sp ventrals 
 
 Lingulepis Gregwa-robusta 
 
 young 6 " 
 
 Lingulella longovalis " 
 
 Obolus discus " 
 
 O sp " 
 
 OrthothecEt, part of tube " 
 
 Hyolithes " 
 
 Bradorona spectator-spinosa .... right v. 
 Indiana ovalis " 
 
 The above assises belong to the lower division of the Btcheminian, 
 and although the matrix imbedding the fossils is fine it alternates with 
 grit sandstones and quartzite in different parts of the division, so there 
 was considerable diversity of conditions when this division was laid down. 
 In the next division, the rocks are coarser and of a more uniform 
 character. 
 
 Assise E. 2 o 
 
 On Dugald brook there are in this assise two species of Lingulella but 
 they are not in such a condition as to be worth study, as the shells have 
 been subjected to much corrosion, 
 
 We have referred here provisionally the fossils of Young point near 
 George river station, as they are in red sandy members of the Etcheminian 
 and some distance above the base of the terrane. The species are : 
 
 Hyolithes cf. tenuistriatus, Lnrs., or princeps. Bill. Fossils of 
 
 Leptobolus atavus, mut. insulse. assise e 2a 3. 
 
 Lingulella Selwyni. 
 
 Lingulepis Roberti. 
 
 Obolus discus. 
 
 Billingsella retrofiexa. 
 
 Holasaphus centropyge. 
 
 A Paradoxidoid trilobite. 
 
 A Eurypterid (?) crustacean. 
 
80 
 
 Assise E. 26. 
 
 The rock is a dark purplish gray sandstone, with abundant grains of 
 non-kaolinized red feldspar. The sandstone is strongly cemented, and has 
 some small calcite veins ; from this and from other conditions in this rock, 
 it would appear that the cement is in part calcareous. There is enough 
 iron in the sandstone to give it a rusty brown color when weathered. 
 The rock contains "pieces of black slate and small pebbles of quartz. 
 
 Acrothyra signata-tarda ventrals 1, dorsals 
 
 Lingulepis longinervis " 9 " 9 
 
 Orthotheca, tube 2 
 
 Bradorona perspicator-magna, right " 2, left v. 
 
 Assise E. 2c. 
 
 J, .] , ., The rock containing the fossils is a fine grained greenish gray sandstone 
 
 assises s 26 with purplish clouding, but the main body of the assise is a purplish gray 
 feldspathic sandstone. The fossils found in this assise were : — 
 
 Acrothyra signata-orta ventrals 3, dorsals 2 
 
 Bradorona observator-lsevis, right valve 2, left v. 
 
 This is the highest assise in which the Lower Etcheminian Fauna was 
 found; above this, in the next division new species come in, and one new 
 genus appears. Between the two fossiliferous zones is a thickness of 
 about 50 feet, in which only broken and imperfect Lingulella, were 
 collected. In this thickness of barren measures though the rock still 
 remains coarse and sandy, the purplish red color has disappeared, and the 
 gray color prevalent in the upper division, is found. 
 
 Assise E. 3a. 
 
 The fossiliferous layers are of lavender gray or pure gray shale, 
 weathering yellowish in the cracks, so probably containing iron-carbonate. 
 There is some felsite debris or feldspar grains, and minute spangles of 
 white mica. The species present are : — 
 
 Acrothyra proavia-prima ventrals 7, dorsals 10 
 
 Acrothele abavia " 4 " 1 
 
 Leptobolus sp , " " 1 
 
 tingulella sp " 1 " 
 
 Obolus lens " 1 " 
 
81 
 
 Assise E. 3 b. 
 
 A bed of purplish gray shale with diffused hematite (giving the rock a Fossils of the 
 purplish gray streak) contains the fossils. There are quite minute spangles of e 3, viz. a 6 
 of white mica. The fossils of this layer are much corroded and do not ^°^ ^■ 
 show good surfaces. 
 
 Fossils — 
 
 Acrothele aba via ventrals 12, dorsals 21 
 
 A avia (?) , " 1 " 1 
 
 Leptobolus atavus " 5 " 7 
 
 Obolus lens, youngvtl. 2. " 4 " 3 
 
 Trilobite a pleura with a deep furrow 1 
 
 Assise E. 3tf. 
 
 A considerable body of gray and purplish gray shale, with very minute 
 spangles of gray mica, " Bretonensis Shale." 
 
 Fossils — 
 
 Acrothele avia ventrals 5, dorsals 7 
 
 A puteis " 14 " 10 
 
 Leptobolus atavus " 32 " 33 
 
 Obolus Bretonensis, young vnt. 1 " 6 " 4 
 
 Bradorona spectator-sequata . . right v. 1 left v. 2 
 
 Of the Acrotheles above named, the first was found on Dugald brook, 
 and the second on Gregwa brook. 
 
 Assise E. 3e. 
 
 In this assise the gray shales become iiaggy, and split into layers \ to 
 3 inches thick ; the fissile condition appears to be due to layers covered 
 with fossils alternating with thin beds in which the shells are less abun- 
 dant. The rock has fine spangles of sihery gray mica. 
 
 Fossils — 
 
 Acrothyra proa via ventrals 160, dorsals 160 Fossils of the 
 
 ■' '^ „ assise E 3f. 
 
 A crassa " 1 " 
 
 Acrothele avia " 9 " 1 
 
 A abavia " 5 " 
 
 Leptobolus atavus " 69 " 63 
 
 L . coUicia " 18 " 26 
 
 6 — c. K, 
 
82 
 
 Lingulella, sp , ventrals dorsals 1 
 
 Oboluslens " 17 " 16 
 
 O longus " 3 " 1 
 
 Bradorona observator-ligata. right v. 2 left v. 2 
 
 Bradoria scrutator " 3 " 1 
 
 B vigilans " 6 " 2 
 
 B rugulosa " 5 " 3 
 
 Indiana ovalis " 1 " 1 
 
 Schmidtella(?) pervetus.... " 2 " 1 
 
 S ^?) acuta " 3 " 3 
 
 Assise E. 3/ 
 
 Gray shale more sandy than the assise below ; some beds havs a purp- 
 lish tint ; the spangles of a silvery mica, are larger than those of E. 3«. 
 Some of the highest beds are flaggy and more silicious. 
 
 Fossils of the Aorothyra proavia-prima ? ventral 1, dorsal 
 
 assises 3/. ^j^ crassa ? . . . . " 1 " 
 
 *Acrothele proles '• 23 " 12 
 
 Leptobolus atavus " " 1 
 
 *L coUicia " 6 " 2 
 
 *L var. coUis . . , . " 21 " 16 
 
 Hyolithes, part of tube 1 
 
 Leperditia (?) rugosa ventral 1, dorsal 
 
 Bradorona perspicator-major.. . right v. 1 left v. 
 
 *Bradoria scrutator " " 1 
 
 Escasona rutellum " " 2 
 
 Indiana lippa " 2 " 2 
 
 *Solenopleura Bretonensis, heads 2, cheek. 1, pleura 3 
 *Eurypteroid Crustacean ? head 1. 
 
 Though we have associated this assise with the Upper Etcheminian 
 Fauna, there are some changes in its species from the typical grouping 
 of t^at fauna. Aerethele avia is replaced by A. proles, to which there is a 
 resembling species in the Paradoxides lamellatus 8ubzone in New Bruns- 
 wick ; also the large Leptobolus is chiefly a variety of L. collicia. The 
 presence of a Solenopleura might also be thought to indipate connection 
 with a higher fauna, but it has not the short eye-lobes of the species of 
 the Paradoxides Zone, and so may be considered more primitive. We 
 have therefore thought it advisable to follow the lithological indications, 
 and inclu(je this assise in the Etcheminian. 
 
 •The species marked with an asterisk were found at GilHs, Indian brook. 
 
83 
 
 Fossils of the EicHEMiNiAjf terrane. 
 
 Though remains both of Hyolithes and Orthotheca have been found at 
 several horizons in the Etcheminian terrane, only at one locality are 
 they in such a condition of preservation as to render it possible to make 
 any attempt at designating the species. 
 
 ORTHOTHECA, Novak. 
 
 This genus is represented at no less than five horizons of the Lower 
 Etcheminian, but in all cases the material representing the tubes of these 
 worms is so imperfectly preserved that no specific reference can be 
 made. 
 
 HYOLITHES, Eichwald. 
 
 Hyolithes ef. tenoistriatus, Linrs., PI. TX, figs. 4o and h. 
 
 A large species of this genus occurs in company with Linguldla 
 Sdwyni in the gray sandstones of Young point, which is nearly related 
 to the above Swedish species. It also resembles the Bohemian H. 
 maximus, Barr., and the American U. princeps, Bill. 
 
 Apical angle about 12°. No groDves were observed within the margins 
 on the dorsal side and no furrow at the median line on the ventral side. 
 This valve is somewhf^t flattened on the sides but much more convex than 
 the dorsal ; on the average it is three times more convex, but the relative 
 convexity is variable. The edge of the orifice of the shell on the ventral 
 side is slightly bowed upward in the middle, and near each end is a sinus 
 where the growth line curves downward and then upward before crossing 
 over to the dorsal side, hence the rising arch of the edge on the dorsal 
 side belongs partly to the ventral side. 
 
 The £^ngles between the dorsal and ventral sides are sharp, especially 
 in the apical half of the shell. The lip on the dorsal side is strongly 
 arched upward, and the surface striae correspondingly curved. 
 
 Sculpture. — Qn both sides are distioft transverse striae, but no longi- 
 tudinal striae. The inner surface of the shell is smooth and daes not 
 show grovth Hues. 
 
 Size of the tube. Width at the aperture 14 mm. Shorter diameter 
 at aperture 8 mm. Length of tube supposed to be about 50 mm. 
 The lip projects above the tube about 5 mm. 
 
 Horizon and locality. — Assise E. 2 (a ?) at Young point near G«qrge 
 river station, N.S. 
 
 61— c. B. 
 
 Hyolithes cf. 
 tenuis triatus. 
 
84 
 
 This species has a sharper emargination at the lateral angle of the 
 aperture than is shown for H. tenuistriaius. Billings speaks of a similar 
 notch in his species If. princeps, but Mr. Walcott does not depict this 
 feature in the examples he ascribes to Billings species. The Cape Breton 
 species diflfers from H. excellens, Bill., in the sharper lateral angles of the 
 tube, (fee. 
 
 Besides this species there are fragments of the tubes of Hyolithes at 
 three other horizons of the lower Etcheminian ; they are, however, in poor 
 preservation, and we have not been able to recognize the opercula of any 
 form of this or the preceding genus in the Etcheminian rocks of Cape 
 Breton. 
 
 In the Upper Etcheminian of this island we have not found the remains 
 of any Hyolithidse, though it is apparently in this part of the Etcheminian 
 terrane that they occur at Smith's Sound in Newfoundland. The genus 
 Orthotheca is exhibited there in great variety. On that sound the Etche- 
 minian beds consist of fine argillaceous sediments of a red color, with 
 some thin limestone beds, while in Cape Breton the Hyolithes-bearing 
 beds are mostly coarse and sandy and abound in effusive volcanic materials. 
 The difference in the genesis of the sediments in the two regions may ac- 
 count for the perfect condition of the fossils in the one, and their frag- 
 mentary state in the other. 
 
 1. — Development of the genera Aorothyra, Acrotreta and Acrothele. 
 
 DeveloDment '^^^ value of small species of fossils in determining geological horizons 
 of the Genera is well shown in TuUberg's monograph on the Agnosti, of which genus 
 Acrotreta and certain types are peculiar to special horizons of the Cambrian and of the 
 Acrothele. Ordovician. A small fragment of rock only has been found sufficient, 
 when containing certain Agnosti, to determine the age of a group of strata. 
 I hope it may hereafter be possible to use the three genera above men- 
 tioned in a similar way for determining the age of parts of the Etche- 
 minian and the higher Cambri.an, where these genera occur. It is as a 
 contribution to this object that the writer presents here descriptions of 
 sucn species and varieties as have been recognized in the Canadian 
 Cambrian rocks. 
 
 It will be seen that so far as our knowledge goes, the first two genera 
 are among the oldest that have been recognized in the Cambrian rocks of 
 Eastern Canada, since they are found along with the volcanics that lie at 
 the base of the Palaeozoic terranes, as well as higher up in jthe Cam- 
 brian ; and they were distinct from each other, even at that early time. 
 The following table shows the distribution of these early forms of 
 Brachiopods in the Basal Cambrian rocks and their relative abundance at 
 Dugald brook at the several horizons at which they occur ; 
 
85 
 
 Distribution of Aceothyea and Aceoteeta in the Coldbeookian 
 AND Etcheminian OP Cape Beeton. 
 
 
 8 
 
 g 
 
 1 
 
 Etcheminian. 
 
 These species and mutations are 
 
 described in the following 
 
 pages. 
 
 1 
 
 2 
 
 3 
 
 
 a 
 
 b 
 
 _7 
 
 c 
 
 d e 
 
 % h c 
 
 a 
 
 b c 
 
 d e 
 
 / 
 
 Aorothyra signata 
 
 
 prima 
 
 18 
 
 
 
 
 
 
 
 
 
 sera 
 
 
 
 59 
 6 
 
 
 
 
 
 
 
 
 
 
 
 24 .. . 
 
 
 
 
 
 
 
 
 orta 
 
 
 
 
 3 
 
 
 
 
 
 A proavia 
 
 
 
 
 
 
 
 
 
 6 160 
 
 
 A prima 
 
 
 
 
 
 
 
 7 
 
 
 '>^ 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 Acrctreta papillata 
 
 
 
 1 
 
 9 
 
 25 
 
 
 
 
 
 
 A prima 
 
 1 
 
 
 
 
 
 
 
 
 
 
 A sp 
 
 
 
 1 
 
 1 
 
 
 
 
 
 
 
 1 
 
 
 
 1 1 i 
 
 
 
 Distribution 
 to Aorothyra 
 and Acrotreta 
 in the Basal 
 Cambrian. 
 
 N. B.— The figures in the columns show the number of individual shells examined. 
 The horizons where the tt/pes of these species are found are marked by heavy faced 
 numbers. Only the ventral valves are recorded in this table. 
 
 AOROTHYRA. 
 
 In studying the earliest strata of ttn Eo Paleozoic of the island of The genus 
 Cape Breton in Nova Scotia, Canada, the author has met with a form °'°^ '"^*' 
 already described in the pages of the Bulletin of the Natural History 
 Society of 'New Brunswick as an Acrotreta,* but which, from more perfect 
 knowledge of the shape, habits and structure, he now thinks should be 
 set off as a separate genus with the following characters : 
 
 Quite small Brachiopods having the ventral valve elongate-conical, with 
 the apex either overhanging the cardinal line, or but little in front of it. 
 Orifice nearly circular, often oblique. Inferior with a long, narrow, or a 
 quadrate visceral callus, extending forward from the foramen about a 
 third of the length of the valve and widening as it goes. 
 
 *Acrotreta proavia, Bulletin of the Natural History Society of New Brunswick, vol. 
 iv., p. 203. 
 
86 
 
 A distinct, usually high, cardinal area extends from the foramen to the 
 cardinal line. 
 
 1 
 
 Dorsal valve as in Acrotreta. 
 
 The difference in the form of the 
 ventral valve distinguishes this genus 
 from Acrotreta and is accompanied by 
 difference of habit, etc. In Acrotreta 
 the visceral callus is concentrated 
 around the foraminal passage, and the 
 shell appears to have been of sedent- 
 ary habit, since the ventral valve in 
 many cases is found fossil in such an 
 attitude as to show that it stood in a 
 vertical position in the mud of the sea 
 bottom when the animal which inha- 
 bited it was living, the opening of the 
 valve being uppermost. No such uni- 
 formity of attitude characterizes the 
 dorsal valve. 
 
 We find that the ventral valve in 
 Aero thy ra assumes quite a different 
 attitude. It lies in very many cases 
 on its side, and usually with the open- 
 ing of the valve uppermost. Moreover 
 it is to be noted that on successive 
 layers these valves lie with the umbo 
 oriented in a fixed direction. From 
 this it may be inferred that they give 
 evidence herein of the action of a cur- 
 rent, flowing in a definite course and sweeping the valves in the direc- 
 tion towards which the current set. They may have swung in this direc- 
 tion by the pedicle while the animal was living ; or when swept away by 
 the flowing water, have presented the point of least resistance to the cur- 
 rent, as they sank to the bottom. In either case we must regard Acro- 
 thyra as living under different conditions from Acrotreta, which, as we 
 have remarked, apparently had the apex of the ventral valve buried in 
 the mud. It is in accordance with these conditions that we have in 
 Acrothyra a visceral callus developed along the median line of the ventral 
 valve, as is the case in Lingula and other allied genera ; and Lingula, 
 as is well known, had a long pedicle. 
 
 Acrothyra proavia, mut. prima — 
 1, Ventral valve — 2, Mould of the same 
 — 3, Same in profile — 4, Dorsal valve-5, 
 Mould of the same- 6, Same in profile. 
 All magnified V Upper Etohemin Shale, 
 0. Breton, N. 3. 
 
87 
 
 ACROTHYEA SIGNATA. Plate I, flg8. 2 o-e. 
 
 Bulletin Nat. Hist. Soc. of New Brunswick, vol. iv p. 377, pit 
 xiii, figs. 2 a-e. 
 
 Ventral valve — Oval, pointed at the umbo, beak depressed and sides Acrothyra 
 compressed. Hinge area oblique. Interior. — There is a strong narrow 
 callus, one third of the length of the valve, bounded by a raised ridge at 
 the sides and in front ; at the front of this callus is an oval pit, from 
 which a groove runs backward nearly to the apex of the shell, where it is 
 supposed to connect with the foramen. Outside the callus, on each side, 
 near the margin of the valve, are lenticular marks of the lateral muscles. 
 About the middle of the valve the position of the anterior adductors is 
 indicated by a faint impression of the lozenge or " heart-shaped " depres- 
 sion. The margin of the valve is thickened. 
 
 The dorsal valve is orbicular, strongly convex, and has a somewhat . 
 triangular appearence, because of the sides being depressed from the 
 umbo, and because the front is strongly bent downward. Interior. — 
 This shows a sharp, thin, median septum, for half of ihe length of the 
 valve. This ridge is broader and more distinct at the front ; at each 
 side are lateral obscure ridges diverging from the umbo. Outside of 
 these ridges are the lenticular imprints of the lateral muscles. 
 
 Sculpture. — The surface of this shell (which perhaps is not the real 
 outer surface) is shining, and has fine concentric ridges visible only 
 with a lens. 
 
 Size. — Length of the ventral valve, 3 mm. ; width, 2 mm. ; depth, 1 
 mm. In the dorsal the length and breadth are equal, and the depth is 
 less than that of the ventral. 
 
 Horizon and locality. — This species is found in Assise 6 of the lowest 
 Etcheminian division at Dugald brook, a branch of Indian brook in 
 Escasonie, N.S. On a cursory examination the ventral valve of this shell 
 might pass for that of a Lingulella, but the closed deltidial area is that of 
 Acrotreta and Acrothyra ; the form of the dorsal and the nature of the 
 interior show that the species is closely related to Acrotreta. 
 
 Acrothyra signata sera. PI. I, figs. 3 a-f. 
 
 Bulletin Nat. Hist. Soc. of the N. Brunswick, Vol. iv, p. 383, pi. xiii, figs. 3, a-f. 
 Valves corneous, thick, especially the ventral. General form orbicular, Acrothyra 
 with the umbo of the ventral projecting. 
 
 Ventral valve nearly circular in outline, and with the back either 
 straight, or slightly hollowed near the apex, and rounded down toward 
 
88 
 
 the front margin. The margin is somewhat straightened at the hinge, 
 and there is a depressed pseudodeltidium, with a narrow striate area on 
 each side. The area is at right angles to the base of the valve, which, 
 when viewed from the side, has the margin somewhat arched up at the 
 front and back. Interior. — This has near the hinge a thick rectangular 
 callus, hollowed at the middle, with a depression that deepens toward the 
 hinge ; from this it is divided by a low transverse ridge, behind which 
 is a pit leading to the foramen, which is just behind the umbo. On each 
 side of the callus, two low ridges extend forward at a wide angle, and 
 limit the area occupied by the lateral muscle scars. The position of the 
 central group of muscles in front of the callus is not clearly defined. 
 
 The dorsal valve is orbicular and the umbo depressed. Two broad 
 obscure ridges radiate from the umbo to the sides of the valve. When 
 viewed sidewise the valve is seen to be bent down both at the anterior 
 and posterior ends. Interior. — The most prominent feature is the median 
 septum, which is usually visible from one-sixth of the length of the valve 
 from the back, to the middle of the valve. A pair of diverging grooves 
 originate at the hinge line, and forward, towards the sides of the valve, 
 divide off the space occupied by the impression made by the lateral 
 muscles. Midway between these grooves and the median septum, are 
 two faint vascular ridges. The margins of both valves are thickened and 
 flattened. 
 
 Sculpture. — This consists of fine concentric ridges with smooth intervals 
 between ; the known surface is smooth and shining, but there are frag- 
 ments of what appears to be an outer layer, with a dull, minutely granu- 
 lated surface. The surface is often ridged with growth lines, especially 
 toward the anterior margin. 
 
 Size. — Length and width of the valves equal, 2|^ mm. The depth of 
 the ventral is 1^ mm. ; that of the dorsal, 1 mm. 
 
 Horizon and locality. — The Assise Ic of the Etcheminian at Dugald 
 brook, Escasonie (C.B.) N.S. 
 
 This differs from the type in the shorter and wider shell, upright hinge 
 A characteris- *'"®*' ^i^S'" visceral callus, and straighter bick of the ventral valve. 
 
 tic Etohemi- From A. signata prima in the more regularly conical form of the ventral 
 man genus. . . i i -n i 
 
 valve. This genus is particularly Etcheminian, there being two species and 
 
 several varieties or mutations in the strata of this age. It seems likely 
 
 Lingulella (?) injiata of the Protolenus Fauna belongs to Acrothyra ; if so, 
 
 the genus ranges up into the base of the St. John terrane. 
 
89 
 
 Oonotreta, of Walcott, an Ordovician (Trenton) genus is a later 
 development from the Acrotretoid phylum, differing in the form of the 
 visceral callus, which is pointed in front, in place of expanding, as in 
 Acrothyra. Analogy, however, would lead us to infer that this genus 
 also was free-floating by a long pedicle, and not sub-sedentary, like many 
 species of Acrotreta. This type of Brachiopod — Acrothyra — is one of the 
 earliest known in the Palaeozoic rocks of Canada, being found in shaly 
 layers in the midst of the eruptives which mark the advent of Palaeozoic 4e*'lnuJ °^ 
 Time in Eastern North America. 
 
 ACEOTYRA SIGNATA— TARDA. PI. II, figs. la-d. 
 
 Bulletin Natural History Society of New Brunswick, vol. iv. p. 364, 
 pi. xiv, figs. 1 a-d. 
 
 Only the ventral valve known. This is tumid, with a broad low umbo, 
 and convex on the median line. Interior. — Distinguished by two short jyjutation 
 prominent grooves that end abruptly, short of the end of the callus ; the tarda, 
 callus is narrow and has a low ridge along the middle ; it ends 1| mm. from 
 the hinge, and the two lateral grooves are about 1 mm. apart. Outside of 
 the two grooves above named are low crescentic ridges in front of the lateral 
 extensions of the hinge line, that enclose the scars of the lateral muscles. 
 
 The dorsal valve has not been separated from that of Acrotreta papillata, 
 which occurs with it. 
 
 Sculpture. — This, on the lateral slopes of the valve, consists of fine, 
 closely set ridges, visible only with a lens. 
 
 Size. — Length, 2J mm.; width, 3 rnm.; depth, 1| mm. 
 
 Horizon and locality. — In the gray shales of E. 1 c and d at Dugald 
 brook, Escasonie, (C. B.) N. S. Common in the latter assise. 
 
 This mutation is distinguished from Acrotreta papillata, with which it 
 is associated, by the form of the callus, etc.. and from Acrothyra signata 
 (typical) by its flatter callus and deeper and shorter lateral grooves ; the 
 same characters distinguish it from A. signata-prima axiA A. signata-sera. 
 
 Acrothyra signata — oeta. PI. I, figs. 4 a-J. 
 
 Bull. Nat. Hist. Soc. of N. B., vol. iv, p. 385, pi. xiii, figs. 4, a-f. 
 
 This rather tumid form has an overhanging beak. Ventral valve broadly Mutation 
 ovate, bluntly pointed, convex along the back, especially toward the front °'^'^- 
 
90 
 
 of the valve, where the curve becomes abrupt. Interior — A callus about 
 three times as long as its width in front, extending from the beak one- 
 third of the length of the valve, sometimes there is an apophysis in front 
 of it, of equal width, sometimes an apparent extension of the callus, with 
 a median ridge dividing it lengthwise. The callus usually has a transverse 
 raised thread towards the posterior end, and sometimes another near the 
 front. A faint, narrowly triangular hollow, divides the callus from the 
 impression of the lateral muscles. 
 
 The dorsal valve is oblately orbicular in form, with inconspicuous umbo. 
 The valve is somewhat depressed in the middle and toward the front. 
 Interior — This part of the valve exhibits a medium septum in the poste- 
 rior quarter of the valve, and behind it two lateral septa, that fork from 
 near the umbo ; the place of the lateral muscles is faintly marked. 
 
 Sculpture. — Of fine concentric ridges, as with other forms of this 
 species. 
 
 Size. — Length of ventral, 2 mm.; width, If mm.; height, 1 mm. to 2 
 mm. Dorsal length, If mm.; width, 2 mm.; height, about ^ mm. 
 
 Horizon and locality. — Fine, greenish-grey calciferous sandstone of E. 
 2 c. at Dugald brook, Escasonie. Not rare. 
 
 This mutation shows a change in the direction of A. proavia of a 
 higher horizon described below. 
 
 The ventral valves lie on their sides on the layers of the rock, but some 
 dorsals are on edge. 
 
 AOEOTHYEA PROAVIA. PI. 11, figa. 2 a-g and 3 a-f. 
 
 Acrotreta proavia, n. sp. Nat. Hist. Soc. N. B. Bull., Vol. iv, p. 203, 
 pi. iii, figa. 2 atoj.; ibid, p. 386, pi, xiv, figs 2 a-g, and 3, a-/. 
 
 Aorothyra Shell-substance calcareo-corneous. The thin outer crust sometimes 
 
 proavia. wanting from corrosion, abrasion or absorption. 
 
 Ventral valve oblique conical, with a prolonged beak. Cardinal area 
 narrow, as is also the pseudo deltidium ; in the pseudo deltidium near the 
 apex is a small oval tubercle, between which and the apex, the foramen 
 is supposed to be situated. The valves slope evenly down from the apex 
 to the anterior and lateral margins. No good examples of the interior of 
 this valve have been obtained ; imperfect ones show two vascular lines 
 enclosing a narrow visceral callus, and extending as far down from the 
 apex on one side, as the hinge area does on the other ; the front margin 
 exhibits on the interior a row of about ten radiating vascular ridges. 
 
91 
 
 This valve is often undulate with one, sometimes several strong grooves 
 concentric to the umbo, marking periods of rest in the growth of the 
 shell ; corresponding ridges are found on the deltidial area. 
 
 The dorsal valve is round, and broadly rounded in front ; the contour 
 of the surface is varied by a moderate projection of the jimbo behind, and 
 by a slight flattening of the valve in front, giving the valve a rounded, 
 slightly triangular relief. The interior has the impression of a pair of 
 muscles in the umbo, whence a low ridge extends forward across the 
 valve. Mot infrequently the edges of this valve are flattened, and one 
 or more grooves, concentric to the umbo, marking stages of growth, 
 indent it. 
 
 Sculpture. — A strong lens reveals a series of concentric strife on the 
 surface on some examples of this shell, there being about 20 in the space 
 of a millemetre. Between these ridges a still stronger magnifier (1 inch 
 objective) shows a fine granulated surface with occasional rows of coarser 
 granules, parallel to the concentric strire. On the inner, chitinous surface 
 there is a similar ornamentation, but less distinct than that on the sur- 
 face of the outer layer. 
 
 Size. — Length of the ventral valve in the largest examples, 3 mm. ; 
 width, 2 mm. The dorsal valves in both diameters is 2 mm. Depth of 
 the ventral valve from the beak 1 ^ mm. ; that of the dorsal at the middle, 
 J mm. A great majority of the valves are smaller and of the size given 
 in the original description. 
 
 Horizon and locality. — In the Assise e, common (and less common in 
 d where it is larger) of the upper Etcheminian, Dugald Brook, Escasonie, 
 Cape Breton. Very thin shells are found on the highway at V. McPhee's 
 in Assise e. 
 
 There is a good deal of variation in the form of the ventral valves of this 
 species. The majority are of the dimensions given, but sometimes the 
 width of the valve is equal to the longest diameter. Also the concentric 
 furrows of growth are in some examples so profound as to give the ventral 
 valve, when slightly distorted obliquely, the appearance of a minute 
 Raphistoma. 
 
 This species differs from all others of the Acrotretinse known to me, except Attitude of 
 L. inflata of the Protolenus fauna, in the high overhanging apex, which ^'^^ *°^^' ' 
 in the typical form projects one-quarter beyond the base of the valve, but 
 in one variety from Assise e, one-third beyond. As a result of their form, 
 the ventral valves of this species, in place of standing erect like many of 
 those of the genus Acrutreta, rest on the dorsal side, on the layers of the 
 shale in which they are imbedded, and except for their marked convexity 
 
92 
 
 Resemblance 
 to Hyolithes. 
 
 Characterizes 
 the Upper 
 Eteheminian 
 Fauna as A. 
 aignata does 
 the Lower. 
 
 Additional 
 characters of 
 the species. 
 
 might be mistaken for those of a minute Lingulella. As they occur 
 scattered over the layers of the shale they also strongly recall the ordi- 
 nary aspect of the conical teeth of fishes, brilliant with black enamel. 
 
 No described species of Acrotreta is as small as the more abundant 
 valves of this species, though A. gemmuld of the Protolenus fauna approa- 
 ches it in that respect.* 
 
 Sir William Dawson has called attention to the resemblance in struc- 
 ture between the shells of Hyolithidse and the Brachiopoda, and has com- 
 pared the ventral valve of a Brachiopod to the tube of a Hyolithes. Had 
 Sir William been acquainted with this species he would have found it a 
 good example for compai-ison. This will be seen if the ventral valve be 
 so oriented as to make the areal side correspond to the ventral side of a 
 tube of Hyolithes. The dorsal valve with its round form and excentric 
 umbo, with radiating lines, also resembles the operculum of a Hyolithes. 
 A detailed comparison of this species with certain Hyolitidse has been 
 made in an article contributed to the Royal Society of Canada (Trans. 
 New Ser. Vol. VII., Sec. IV. p. 93). 
 
 A study of layers of the shales of the horizon E. 3 <"., studded with the 
 valves of this species, failed to reveal any ventral valves, showing clearly 
 a thickened callus. For the relationship of this species we have therefore 
 to depend on the lovms pri'na and crassa, both of which possess a narrow 
 callus. These show that these three forms are of the tame genus as A. 
 signala, but of a different species, and reveal a series ia the upper Etehe- 
 minian Fauna parallel to the Signati of the lower fauiia ; they are distin- 
 guished from the latter by their narrow visceral callus. The absence of 
 a thickened callus in the typical form of A. proavia would seem to show 
 that the pedicle in this form was slender and weak, and from the fact that 
 this shell, above all its fellows, shows a perfect orientation in one direc- 
 tion, as imbedded in the shale, there is a presumption that the pedicle 
 was also long, enabling the animal to swing in the currents of the sea in 
 which it lived. Often the ventral has an even slope along the back, 
 but many old valves, especially long ones, show from two to three 
 heavy concentric ridges, marking stages of the growth of the shells. 
 
 Interior. — The ventral valve of this species has a quite small tubercle 
 in front of the foramen. Two-fifths from the apex of the ventral valve 
 there is a shallow depression on the interior surface, which, by analogy 
 with mut. prima should mark the position of the central muscle scars. 
 On each side of the shallow depression a shallow groove runs forward 
 toward the front of the valve. Some examples show a median and two 
 lateral septa in front of the shallow depression. Faint ridges, running 
 
 * Trans. Roy. Soo. Can. Vol. xi, p. 87, pi. xvi, figs 2 a to d. 
 
93 
 
 forward on each side of the front slope of the ventral valve, may indicate 
 the position of vascular trunks. 
 
 Interior. — The dorsal valve has inside a median and two lateral ridges. 
 On some valves the median ridge extends only so far as to divide the pits 
 of the cardinal muscle ; in others it extends to the middle of the valve. 
 A pair of median pits are sometimes visible near the end of the median 
 septum, one on each side of it. 
 
 ACROTHYEA PROAVIA-PRIMA, PI. II, figS. 4 O-f. 
 
 Bull. Nal. Hist. Soc. of N.g. vol. iv, p. 389, pi. xiv, figs. 4 a-f. 
 Ventral valve triangular-ovate, about twice as long as wide, prolonged Mutation 
 
 T)nn[i3i 
 
 into a long pointed beak, and rounded and bent down in front. 
 
 Interior. — This exhibits a long narrowly tapering callus originating in 
 the beak at the foramen ; the callus is a third of the length of the valve, 
 or more. In front of the callus is a shallow transverse depression, 
 marking the position of the central group of muscles. 
 
 The dorsal valve is nearly circular, projecting at the back, where there 
 is a somewhat low 1 eak, and rounded down more at the front than the 
 sides. Interior. — A median septum is visible, dividing the pits of the 
 cardinal muscles. A shallow median ridge traverses the middle of the 
 valve, which is flattened at each side near the hinge. The edge of both 
 of the valves are flattened and thickened, also the apical third of the 
 ventral valve is thicker than the middle of that valve. 
 
 Sculpture. — This consists of a very fine granulation, witli frequent, 
 thread-like, concentric ridges. 
 
 Size. — Ventral valve : length, 3 mm. ; width, 2 mm. ; height of the 
 cardinal area, 2 mm. Dorsal valve, 2 mm. in each diameter ; depth, 
 ^ mm. 
 
 Horizon and locality. — E 3 a = base of the upper Etcheminian shale 
 at Dugald brook, Escasonie (C. B.), N. 8. Frequent. In this rock the 
 ventral valves of Acrothyra lie flat on the layers. Also a valve appar- 
 ently of this form, 3x2 mm,, from E. 3 /!, occurs at Gillis brook, a 
 branch of Indian brook, Escasonie. 
 
 This mutation is distinguished from the type by its greater size and by 
 the possession of a thickened callus. 
 
94 
 
 Variety 
 crassa. 
 
 ACEOTHYRA PROAVIA-CHASSA, PI. II, figS, 5 a-C. 
 
 Bull. Nat. Hist. Soc. of N. B. vol. iv, p. 389, figs. 5 a-c. 
 
 Only the ventral valve known. This is short, tumid and conical. 
 Interior. — .This possesses a narrow callus, four or five times as long as 
 wide, and nearly a third of the length of the shell. At the front of the 
 callus are two small oval scars divided by a faint septum. The callus is 
 concave and extends back nearly to the beak. 
 
 Sculpture. — Some fragments of the surface which are preserved show 
 fine, close set, concentric ridges. 
 
 Size. — Length, 2||- mm. ; width, 2 mvS. ; height, 1| mm.? 
 
 Horizon and locality. — Lower layers of the assise E. 3 e, at 
 Dugald brook, Escasonie (C. B.), N. S, Also a doubtful ventral from 
 E. 3 /. at Gillis, Indian brook, Escasonie. Scarce. 
 
 This mutation is distinguished from the type and from mutation 
 prima by its robust form, and from proavia, the type, also by the posses- 
 sion of a thickened callus. From the mutations and type of A. signata by 
 the narrowness of its callus. 
 
 Of the two species of Acrothyra herein described, signata was found 
 specially to characterize the lower half of the Lower Etcheminian fauna, 
 being found most abundant in the middle measures of this set of beds. 
 It is not, however, limited to these measures, but by mutations is 
 sparingly represented in the upper part of this lower fauna. 
 
 Acrothyra proavia, on the contrary, has been found only in the Upper 
 Fauna, and mostly in its higher part, where some layers are crowded 
 with thousands of these litte shells. 
 
 ACROTRETA. Kutorga. 
 
 Acrotreta 
 
 comparative 
 
 abundance. 
 
 While this genus appears as a contemporary qf Acrothyra in the 
 earliest B^BaJ Qambviftn, it seemingly lived qq ^fter thie l»itter had passed 
 away. But throughout the Coldbmpk '*nd lower EtefeenaiQian mesi^ures, 
 it is quite subordioaite in numbers to Aqrothyra, an(} we have nat fonnd 
 it at all in the upper Etcheminian. Throughout the true C^icnbrian in 
 the Acadian Provinces, hqwever, these conditions were reversed, for, 
 with the doubtful exception of Linguldla (Acrothyra ?) inftata of the 
 Protplenus fauna, an undoubted example of the genus Acrothyra is 
 unknown to me above the Etcheminian horizon, and Acrotreta has full 
 possession of the field in the higher Cambrian zones. 
 
95 
 
 ACKOTRETA, PAPIHATA, PI. Ill, figs. 2 af. 
 
 Bull. Nat. Higt. gee. of N. Bruns'k, vol. iv, p. 390, pi. xv.figs. 2 a-/ 
 (Calcareo-)corneous vg,lves ajoderately arched, nearly ortiicular, ventral Acrotreta 
 valve with » inaderately elevated umbo, one-fifth from the back of the P^P'"^'*- 
 valve ; the back of the vsilve somewhat concave toward the umbo, but 
 convex toward the front margin. There is a concave pfseudo-xleltidium, 
 and the side slopes of the hinge area are convex. Interior — In this 
 the visceral callus is short, sub-circular, and marked at the middle by a 
 deep circular pit ; at its sides, obscure, short, straight, diverging grooves 
 are usually seen within the circular groove that surrounds it. 
 
 The dorsal valve is moderately arched, the slope being steepest toward 
 the umbo, which is but slightly raised. On eaph side of the umbo flat- 
 tened slopes run along the sides of the valve in the posterior half. There 
 is a shallow median sinus on the beak of the valve, which widens toward 
 the front. Interior — Under the beak is a boss from which a median 
 septum runs forward, that forks about a fifth of the length of the valve 
 from the hinge line ; from the space between the forks, at a third of the 
 length of the valve from the hinge, the median septum reappears, widens 
 and terminates at a point nearly a third from the front of the valve. On 
 each side of the umbo are pits of the cardinal muscles and outside these, 
 in advance of them, and near the margin, are large scars of the lateral' 
 muscles. 
 
 The margins of bpth valves are flattened and thickened. 
 
 Sculpture. — This shell has a dviU, minutely granulated surfape, across 
 wWeH run narrow ridges concentric to the umbo, widely s,p»eed io the 
 middle of th# shell, more cJasely arranged t&ward the margis, q,nd closely 
 crowded and nacrow, on each side toward the hinge. 
 
 Size. — Ventral, 2^ mm. long, 2J to 3 mm. wide, and 1^ mm. high. 
 Dorsal, as the ventral, except th t the height is about f mm. 
 
 Horizon a,Tk^ locQ,lit^. — E. 1 d, the Qregwa sfeale of the Etcheminian at 
 Dugald brook, Ep^sonie, (C.B.) N.S. Oonimon. It occurs algo in 
 Assise E. 1 c. 
 
 Vab. lata, pi. Ill, figs. 3 9-c. 
 
 Pull. Nat. Hist. Soc. of N. Brunswick, vol. iv, p. 391, pi. xv, figs. 3 a-c. 
 
 In examples from Boundary brook the form of the callus in the mferior* Variety 
 of the ventral valve varies from a perfectly circular elevation to one that 
 
96 
 
 is somewhat squared at the sides ; the groove outside of the callus is 
 somewhat indistinct. On each side of the foramen is sometimes a short, 
 sharp furrow directed forward. In the dorsal valve the depressed posterior 
 lateral slopes and the somewhat flattened anterior slope give the valve 
 a triangular appearance. The interior shows a pit at the hinge area, 
 which is narrow, and thence a narrow median ridge runs nearly to the 
 middle of the valve. An inconspicuous lateral branch is thrown off each 
 side of the median ridge. 
 
 Horizon and localiiy. — The assise E. 1 d, on Boundary brook, Esca- 
 sonie, (C.B.) N.S. 
 
 ACROTItETA. Sp. 
 
 A species of this genus occurs in the sandstone of E 2a at Youngs 
 point with Lingulella Selwyni. It is rare, and only a dorsal valve has 
 been found. 
 
 Development op Aceotreta. 
 
 Development This is one of the most conservative of the genera of the Cambrian and 
 o oro re a. Qrdovician. Though its species occur at intervals at various horizons in 
 these Systems the uniformity of size and sculpturing is remarkable. Though 
 so uniform as regards their outer surface, the various species of Acrotreta 
 present differences of moulding of the interior of the valves, especially of 
 the ventral valve by which they may be distinguished. This may be seen 
 by consulting the figures of some of the Canadian Cambrian species given 
 on plates iii, iv and xviii, where especially in the moulds of the ventral 
 valves marked differences of form of the inside surface is apparent. As re- 
 gards the moulds of the interiors of the dorsals also, the differences are suffi- 
 ciently marked. (Compare with each other, figures 2_/, 4c and 5A of plate 
 iii, Ig of plate iv, and fig. 2 of plate xviii.) The ornamentation consists 
 of a fine concentric striation, only visible with a strong lens. The 
 size did not increase more than about four-fold in area in the vast 
 space of time included in the Cambrian and Ordovician Systems. Con- 
 trast this with Paradoxides, which increased in area an hundred fold in 
 the first two sub-faunas of the Paradoxides Zone. These sub-faunas per- 
 haps do not cover more than a twentieth of the space of gelogical time 
 represented by the range of faunas in the following table. 
 The series of Acrotreta run in size about as follows : 
 
97 
 
 Size and form op the Ventral Valve in Species of Acroteeta 
 OF the Cambrian and Ordovician 
 
 Horizon 
 
 or 
 Group. 
 
 Coldbrook 
 
 Group. 
 Lower 
 
 Etcheminian. 
 Upper 
 
 Etchemiman. ? 
 Protolenus 
 
 Fauna. 
 Lower 
 
 Paradoxides. 
 Upper 
 
 Paradoxides. 
 Dolgelly, ? 
 Dolgelly, 
 Tremadoo, 
 Tremadoo, 
 Arenig, 
 Llandeilo, 
 II 
 
 Etage D. 
 
 Name and reference. 
 
 A. papillata — prima, PI. xv, figs, la to e 
 
 A. papillata, PI. xv, figs. 2a to/ 
 
 A. gemma, (Bill. ) Walcott* . , 
 
 A. gemmula, f PI- xv, figs, ia to d. . . . 
 A. Baileyi J PI. xvi, figs, la to d 
 
 A. sooialis, v. Seebach,§ 
 
 A. gemma, (Bill.), Waloott* 
 
 A. Diseota,1| PI. xvi, 2a tog 
 
 A. cf. sooialis (Seeb), Brogger** 
 
 A. sipo, PI. xviii, figs. 1 and 2 
 
 A. gemma, Billingsft 
 
 A. suboonioa. Kutorga'JJ 
 
 A. Nicholsoni, Davidson, §§ 
 
 A. babel, Barrande||i| 
 
 In Millimetres. 
 
 t 
 
 a 
 
 2 
 
 24 
 
 14 14 
 
 34 
 
 3 
 
 3 
 3 
 
 14 
 
 3 
 
 If 
 4 
 4 
 2 
 
 3 
 2 
 4 
 
 4 
 24 
 
 li 
 
 li 
 
 1+ 
 
 2 
 
 24 
 2| 
 
 14 
 
 24 
 2. 
 
 2i 
 
 Table showing 
 enlargement 
 and change of 
 form in 
 8'o'S' Acrotreta. 
 
 B5.C 
 
 2. 
 
 2.4 
 
 1.5 
 
 1.5 
 
 3.- 
 
 1.5 
 
 1.4 
 1.3 
 1.3 
 1.2 
 1. 
 .85 
 .94 
 1.1 
 
 It will be noticed that not only are the later species as a rule larger, 
 but they are proportionately higher. Also we may observe that there were 
 two lines along which there was a divergence in the relative height of the 
 ventral valVe. A Baileyi had low umbones and approximated in form to 
 Linnarssonia, a genus which, so far as has been observed, appeared in the 
 Canadian Cambrian a little before it. The other and main line of develop- 
 ment culminated in the high umboned species of the Ordovician faunas. 
 
 For information regarding several European species of Acrotreta I am 
 indebted to Mr. Gilbert Van Ingen, of the School of Mines, Columbia 
 College, New York. 
 
 * Bui. U. S., Geol. Survey No. 30, p. 98. 
 
 t Trans. N. York, Acad, Soi., No. XXVIII, p. 126. 
 
 t Trans. Roy, Soc, Can., Vol. Ill, Sec, IV, p. 36 
 
 § Braohiopoda Paradox. Beds, Sweden, Linrs. p. 16. 
 
 ir Nat. Hist. Soc, N. B., Bull. No. XIX, p. 275. 
 
 ** Die Silurisch, Etagen 2uud 3, p. 46. 
 
 tt Paleozoic Fossils, Vol. I, pt. 1, p. 216. 
 
 H Monog. Br. Braohiopoda, Vol I, pi. IX. Fischer, Conchyliologie p. 1266. 
 
 §§ Monog. Br. Braohiopoda, Vol. I. pi. XVI, Vol III, p. 338. 
 
 nil Syst. Silur. Bohem, Vol. V, pJ. 95. 
 
 -C. E. 
 
98 
 
 ACROTHELE Linnarsson. 
 AcROTHELE AVIA. PI. V. Figs. la to/ and 2a and b. 
 
 Aerothele Acrothele avia, n. sp. Nat. Hist. Soc. Bull., vol. iv, p. 202, pi. iii, figs. 
 
 avia. . , 
 
 a to h. 
 
 Bull. ffat. Hist. Soc. of New Brunswick, vol. iv, p. 396, pi. xvi, figs. 
 1 a-f and 2 a-b. 
 
 A rather large species with oblately oval valves and a thick horny shell. 
 
 Ventral valve somewhat concave in front of the apex. This valve has 
 a triangular, somewhat convex, high area, including a narrow, slightly 
 convex, pseudo deltidium, divided into two equal parts by an obscure 
 central groove. There appears to be a foraminal opening at the slender 
 pointed apex. 
 
 The interior of the ventral valve is marked by a shallow circular pit, 
 on each side of the pedicle opening ; and behind, at the margin, is a 
 shallow triangular pit, resembling the pedicle groove of an Obol-as. In 
 front of the pedicle opening is a strong oval tubercle, on each side of which 
 extend the ridges that bound the oval centre of the visceral cavity. Four 
 low vascular ridges extend forward from this oval area to the anterior 
 margin of the valve. The parts of the interior of the shell, above des- 
 cribed, are enclosed by an ox-bow shaped groove, resembling the impres- 
 sion of vascular trunks ; these trunks have about four anterior branches, 
 and each trunk extends nearly to the front of the valve. On the lateral 
 slopes of the shell are three crescentic grooves, which may be accidental 
 and due to pressure. 
 
 The dorsal valve is strongly bent down behind and in front. The umbo 
 is slightly prominent, is appressed, and is close to the posterior margin. 
 The sides of this valve have about a dozen radiating, branching, crenulated 
 ridges, that extend to the margin. The interior of the dorsal valve has 
 a strong median septum, extending to the middle of the valve : at the end 
 of this ridge is the central muscle. Scars of the latter are seen on each 
 side of the broad end of the median ridge, near its end. On each side 
 of the median ridge at the cardinal margin are two pairs of muscle scars. 
 From the posterior part of the shell several faint radiating ridges extend 
 toward the front margin. 
 
 Sculpture. — The surface of the valves is marked by irregular, concen- 
 tric, rounded ridges, that frequently anastomose ; and the front of the 
 ventral valve and the sides of the dorsal valve have a number of radiating 
 ribs. The sculpture is very variable ; on the central part of the dorsal it 
 ahows an irregular network of low, rounded ridges ; on the sides of the 
 
99 
 
 valve these ridges are more regular in their course ; and on the margins, 
 especially of old shells, they are stronger and more continuous. There is 
 also much variation in the distinctness of the features of the interior, 
 both of the dorsal and ventral valves, the smoother shells being thinner. 
 There is no trace on the interior of the dorsal valve of the ridges on its 
 lateral slopes. 
 
 Size. — Length 9 mm. ; width 10 mm. or more. Depth of the two 
 valves together 2 mm. or more. 
 
 Horizon and Locality. — In assises d and e of the Upper Etcheminian 
 (E. 3 d and e) Dugald brook, Escasonie, N.S. 
 
 As the outer layer of this shell is thin and fragile, the strong inner Aorothele 
 , . , , , 1 n . ■ , 1 1 1 , avia compared 
 
 layer is the one most commonly exposed, and might be thought the real with other 
 
 surface. The outer surface has an ornate sculpturing, while that of the ^P^^'^s. 
 
 second layer is smoothed. This species of Acrothele is distinct from all 
 
 others by the long tubercle or callus in front of the pedicle opening. The 
 
 ribs of the outer surface of the latei-al slopes of the dorsal valve are peculiar 
 
 to it. A. Matthewi and its varieties have no such ribs. A. Matthewi- 
 
 prima has a granulate-latticed surface, but no lateral or anterior ribs. A. 
 
 Matthewi-costata also has a granulated surface, and ribs on the front of the 
 
 ventral, but none on the sides of the dorsal valve. The varieties of A, 
 
 Matthewi also have the foramen nearer the cardinal margin than is the 
 
 case with this species. 
 
 Examples of this species occurring in the As4se B. Zd differ from 
 those of A. abavia occurring with it, in the thinner corroded valvesi 
 larger size and oblate form ; they are doubtfully referred to this species 
 for the ventral valve is more concave in front of the umbo than are the 
 typical shells occurring in Assise E. 3e. It does not flake at the middle 
 layer of the shell as A. abavia of the same assise does. 
 
 In Assise E. 3d valves appear, which, by their oblate form and surface 
 markings, may, without much doubt, be referred to this species. Not 
 only are they broader than the Acrotheles of the lower assises, but they 
 are larger, some valves attaining 9^ mm. in width. An exterior of a 
 ventral which is nearly one-half wider than long, and an interior of a 
 dorsal about a third wider than its length, are figured. 
 
 In the examples from this horizon the ventrals show surface markings, 
 hinge area and foramen ; their interiors show crescentric grooves of the 
 vascular trunks, and at the margin, prints of its branches. Some of the 
 dorsals show the surface sculpture ; others, which have the interior ex- 
 posed, show median and lateral ridges, vascular lines, <fec. 
 
 7J— c. B. 
 
100 
 
 A. AviA-PUTEis. PI. IV, figs 5 a and 5. 
 
 Variety 
 puteis. 
 
 Bull. Nat. Hist. Soc. of N. Brunswick, 
 
 5, Or-h. 
 
 Vol. IV, p. 398, pi. XVI, figs. 
 
 This seems to be a variety of A. avia. It differs in the possession of a 
 pair of pits, one of which lies on each side of the space between the fora- 
 men and the visceral callus, partly overlapping each. The visceral callus 
 is quite short in this form and has but little prominence. The ridges on 
 the surface of the valve are more regularly concentric than in the type, 
 and more sharply cut ; about ten are found in the space of one millimetre. 
 The cardinal area is curved forward towards the top, and finely striated. 
 The foramen is about a fifth of the length of the valve from the cardinal 
 line, and the front of the callus about a third. Vascular trunks and 
 branches are visible on the surface of the ventral valve as in the type. 
 The dorsal valve does not sensibly differ from that of A. avia. 
 
 Size.— -The largest valve seen was 8 mm. long, and about the same 
 width. 
 
 Horizon and locality. — Found in the Bretonensis shale (E. 3d.) at 
 Gregwa brook, Escasonie, Cape Breton. Frequent. 
 
 Acrothele 
 aba via. 
 
 Acrothele abavia. PI. IV, figs. 3a to d, and 4a and b. 
 
 Bull. Nat. Hist. Soc. of N. Brunswick, Vol. IV, p. 398, pi. XVI, figs. 
 3 a-d, and 4 a and b. 
 
 Outlines of the valve nearly circular. Length of the hinge line less 
 than a third of the diameter of the valve. 
 
 Ventral valve rather flat, with the umbo slightly raised. The umbo is 
 about one-quarter of the length of the valve from the cardinal line. In- 
 terior. — In the examples known from the horizon E. 3a., the interior is 
 smoothly moulded, except along the front slope, where faint vascular 
 grooves may be detected, but in those from E. 36., a visceral callus is 
 faintly outlined, with a swelling on the middle ; some valves here have faint 
 impressions of vascular trunks on each wide of the callus, running forward. 
 
 The dorsal valve has its greatest height near the middle, and has an 
 appressed umbo, close to the hinge line ; the lateral margins, in the pos- 
 terior half, are revoluto. Interior. — A median septum starting near the 
 hinge line, extends across the middle of the valve to nearly one-third 
 from its front ; it is widest in the middle and fades away to a point in 
 front. On each side of it is a vascular grove, the pair radiating from 
 near the umbo and extending nearly to the front margin ; they are nearly 
 
101 
 
 as far apart at the front as half of the width of the valve. Another 
 pair of such grooves, about half as far apart as these, are faintly impressed 
 on each lateral slope of the valve. The visceral cavity is faintly marked 
 out by striated lines in the posterior half of the valve, and has an irregu- 
 lar arched front, projecting near median septum towards the front of the 
 valve. Faint vascular strise are visible on the median area towards the 
 front of the valve. Some examples from the horizon E 3 6 have a shorter 
 septum, and show the position of the central and lateral muscles closer 
 to the hinge line. The shells are more oblate. 
 
 Sculpture. — This is only known near the side of the valve, where it 
 consists of fine, closely set, more or less tuberculated ridges, parallel to 
 the margin. 
 
 Size. — ^Length and width equal, 7 mm. Depth of the ventral valve 
 about of a millimetre ; that of the dorsal 1 mm. 
 
 Horizon and locality. — All the horizons from E. 3a to E. 3e, (except E. 
 3d,) at Dugald Brook, Escasonie, N.S. 
 
 The Acrotheles of E. 3c are much corroded, and do not show the 
 characters well ; they are mostly moulds from which the shell has been 
 exfoliated. One ventral shows well the hollow behind the hinge area, 
 and the foramen. 
 
 Examples from the assises E. 3e. have in the ventral valve quite a small 
 tubercle in front of the foramen ; the visceral callus extends half of the 
 length of the shell, and at each side in front are sometimes seen pits of 
 the adductor muscles : on each side of the callus a groove run out toward 
 the fi;ont margin. Some examples show a median and two lateral septa 
 in front of the callus. Often the shell has an even surface to tbe margin, This the 
 but frequently there are a ipvr strong concentrip ridges that mark stages Acrothel 
 of growth. 
 
 Thq dorsal valve of this species (from E. 3e) has inside, a median and. 
 two lateral ridges ; on some valves the median ridge extends only so far 
 as to divide the cardinal muscles ; in others it extends to the middle of 
 the valve. A strpng pair of median pits are sometimes visible near the 
 end of the median septum. 
 
 This is the oldest undoubted Acrothele detected in the Eopal^ozoic 
 rocks of Eastern Canada. Almost all show only the interior surface, or 
 intermediate layers of the shell. One ventral has a 'cor roded outside, 
 with traces of concentric ridges. 
 
102 
 
 ACROTHELE PROLES. PI. V, figS. 3 05 tO 6. 
 
 Bull. Nat. Hist. Soc. N. Brunswick, vol. iv, p. 400, pi. xvi, figs. 3 ou-e. 
 
 Aorothele General form lenticular with the umbo of the ventral valve projecting. 
 
 The length and breadth of the valve.^ of this species are sometimes 
 equal, though usually the width is somewhat greater. 
 
 The ventral valve is convex on all the slopes, except close to the umbo, 
 where it is slightly concave in front. The umbo is low, and is about 
 one-seventh of the length of the valve from the hinge line, the area is 
 about 1 mm. long and the length of the hinge line nearly one-third of the 
 width of the valve. Interior. — This has an obscurely lozenge shaped 
 callus in front of the foramen, upon which at the posterior end is a small, 
 more elevated portion. On each side of the callus is a pair of vascular 
 ridges, marks of the advance of the central muscles. A pair of short 
 ridges, near the hinge line, are of the nature of teeth outlining sockets for 
 the articulation of the two valves. Faint curving ridges in the anterior 
 part of the valve appear to be vascular trunks ; these fork toward front, 
 and show eight or nine ridges with corresponding depressions along the 
 anterior margin. 
 
 The dorsal valve is more regularly lenticular, but more abruptly bent 
 down behind i ban elsewhere, the umbo is depressed, and not easily recog- 
 nize i. Flattened valves exhibit costae radiating from the umbo, but not 
 reaching the margin. Interior. — This shows a strong, broad median 
 septum extending nearly half of the length of the valve ; at the front it 
 fades away into fan-like ridges that rapidly sink to the level of the valve. 
 On each side in the cavity of the valve, and extending nearly as far for- 
 ward as the median septum and, diverging from it, is a pair of sharp 
 vascular ridges. Outside of these, on the rounded edge of the' valve, at 
 the ends of the cardinal line, are a pair of elongated flattened teeth, that 
 articulate with the sockets in the ventral valve. The margins of the 
 dorsal valve are broad and rolled backward at the edges. 
 
 Sculpture. — This consists of fine, regular concentric ridges that occa- 
 sionally anastomose. There are about eight or ten ridges in the space of 
 one millimetre, the ridges being more widely Spaced toward the margin. 
 
 Size. — The largest valve seen was 12 mm. long ; valves of 9 mm. are 
 common ; the height of each valve is about 1 mm. 
 
 Horizon and locality. — In the shales of E. 3/!, near the top of the 
 Etcheminian at Dugald and Gillis' Brooks. Frequent. 
 
103 
 
 This interesting species seems best represented in Europe by A. Kesemblance 
 i- T • > , , 1 . . » , -r^ , . n ^ to A. coriacea 
 
 coriacea ot Liinnarsson, but that species is of the Paradoxides Zone, Linrg. 
 
 its umbo is further from the hinge line, and the cardinal features are 
 
 different. 
 
 It will be noted that the supposed vascular trunks in this species, 
 Aerothele avia and Obolus (Palceobolus) Bretonensis are far removed from 
 the margins of the valves. 
 
 ACEOTHELE, sp. 
 
 A species of this genus occurs in the flags of Division 2 (6 ?) of the St. 
 John Group at a cutting on the Intercolonial R. R. at Long Island 
 passage, St. Andrew's Channel. The material is too imperfect to de- 
 termine the species. 
 
 Notes on the following table. 
 
 It seems quite probable that when the Acrotheles that have been 
 described from the Lower Paradoxides beds are compared, some of the fol- 
 lowing names may be found to be synonyms, there being five species 
 accredited to the Band c. But it is to be remembered that there are two 
 sub-zones in this band, showing considerable differences in the fauna. 
 To the lower sub-zone of Paradoxides lamellatus (cf. Qillandicus) A. 
 granulata and A. cf. coriacea are to be assigned, and to the higher or 
 sub-zone of P. eteminicus, the other three. 
 
 As Mr. Walcott's species are referred simply to Lower Cambrian, one 
 cannot compare them closely with the others ; but it seems possible 
 that the one referred to A. suhsidua may be some other species, as it 
 occurs with a different fauna than that of the original form, and 
 apparently, by the stratigraphy, should be much older. 
 
 I have ventured to assign White's A. subsidua to the Peltura Zone, 
 because it appears to be the same with a species which occurs in the 
 Mt. Stephen Fauna ; this fauna contains an Ogygia and an Olenoides 
 with other forms which appear to indicate this as the lowest horizon to 
 which it should be assigned. White's species is said by Director Walcott 
 to occur with Asaphiscus and Olenoides, which also appear to be Upper 
 Cambrian forms.* 
 
 Near the same horizon, or perhaps a little higher, would come Bar- 
 rande's A. incohans which occurs in the ' Fauna of Hof ' equivalent to 
 the Tremadoc Fauna. 
 
104 
 
 Pi^t^ributipn 
 of Aorotjiele 
 in the Cam- 
 brian rocks of 
 Eastern 
 Canada &c. 
 
 •aaquin^ 
 
 T-4NCQ-i*<i0;pt^00O&OrHNCQ-*lO<O 
 
 c3 
 
 (3 
 
 1^ 
 
 o 
 
 Pi3 
 d 
 
 M 
 e 
 
 o 
 
 o 
 
 ■s 
 
 
 o 
 
 I— I 
 
 & 
 
 D 
 O 
 
 O 
 
 02 
 
 g.S 
 
 la 
 a o 
 
 If 
 
 i " I 
 
 sniidBjaiBj^aX 
 
 ■simaqd'Bsy 
 BcaauOii^oiQ 
 
 •■Bjn^pa; 
 
 •'Bai[oq«J'Bj^ 
 
 
 I 
 
 i 
 
 'jequin|{ 
 
 X X X X 
 
 Us 
 ^"1-^ = 1 
 
 'sf 
 
 ill?. 
 
 nip 
 
 
 e T-t 
 
 THNCjTjHlOeot^QOaiOiHMCC-^lOCD 
 
 a 
 
 <a 
 
 S5 
 
 3 
 
 .a 
 
 ■a 
 
 S r 
 
 5 
 
 
 
 T^^ 
 
 » 
 
 
 
 
 
 «-:: 
 
 
 -••t" 
 
 OT1 
 
 ^4 
 
 a'C 
 
 Sfl 
 
 . 9 
 
 gd3 
 
 .ya 
 
 a*- 
 
 2^1 
 
 -"1 
 
 1^ 
 
 i^^ 
 
 
 1=' 
 
 «S - 
 
 
 a --a 
 
 •S5 
 
 gSSu^SS 
 
 il^^'ii 
 
 ir^ 
 
 SS 
 
 OS — ^ 
 
 "It-^ So 
 -s ""^ 1 
 
 ot-lO i-H 
 
 e«) . to 
 
 Si* 4^ 
 ^?^ Is 
 
 ?' -^ tt» ** 
 
 a or So 
 
 li« II 
 
 #|5 ii 
 
 •a p. 
 
105 
 
 Among the Acrotheles there are several types of sculpturing of the 
 surface of the valves. The most characteristic is that of fine, short, 
 irregular wavy ridges, such as are found in A. Matthewi and A.granulata. 
 Another type is represented in A. proles, A. gamagei and A. cf. coriacea 
 wherein the ridges become more regularly concentric ; the valves in this 
 group are larger, and the ventral less selliform than in the preceeding 
 one. White's description of A. suhsidua would indicate that there is a 
 third style of ornamentation in the latter species, in which the surface is 
 papillose, yet with concentric lines of growth. 
 
 From the time of its sudden appearance in the base of the Upper Omamenta- 
 Etcheminian group, Acrothele continues to be common until we pass the surface of the 
 Lower Paradoxides beds ; from this point upward they are rarely met ^l^^s m this 
 with in Eastern Canada. It is thus in Canada apparently more limited in 
 range than Acrotreta, which extends up into the Ordovician. Its range 
 also diflfers from that of Acrothyra, which is a common genus in the Lower 
 Etcheminian, can be found even as far down as the Coldbrook, and also is 
 present with Acrothele in the Upper Etcheminian, but hardly invades 
 the Protolenus fauna ; where, as well as in the Lower Paradoxides beds, 
 shells of Acrothele are common. 
 
 Neither in Eastern C^aiuicla nor in Scandinavia do we find any Acrothele Range of the 
 reiported from the Upper Cambrian, but in these countries the fine dark ff^'stera 
 ocean muds that were then accumulating were not favourable to the Canada, 
 growth of Acfothele. Lindstrom however reported an undescribed 
 species from the Ceratopyge limestone (equivalent to the Trunadoc 
 ■Group of Wales) and from the occurrences in Bohemia and western 
 North America it would appear that the genus extended up into the 
 Ordovician or at least to its borders. 
 
 LEPTOBOLUS, Hall. 
 
 At several horizons in the Etcheminian terrane we have met with small Characteris- 
 Braohiopods which seem to agree with Hall's genus above cited better j^j„° ^^ 
 =than with any other. Such forms have usually been- included in Lingu- 
 lella, but in addition to their minute size they are separated from that 
 genus by important characters. 
 
 These little shells have thin test, weak umbones ; vascular trunks are 
 8 tuated near the lateral margins, and both the central and lateral muscle 
 in^both valves are advanced far toward the front of the valves. They are to 
 .be found both in sandy and muddy layers often mingled with Lingulella, 
 
 ♦Bull. U. S. Geol. Surv. No. 30, p. 40. 
 
106 
 
 etc., though seeming to prefer a sandy bottom, ia clear quiet water 
 They abound in the Upper Etcheminian, and are spread vertically from' 
 the Coldbrook terrane to the summit of the Cambrian. 
 
 Leptobolus atavus, pi. VI, figs. 2 a — g. 
 
 Leptobolus L. atavus, n. sp. Bull. Nat. Hist. Soc, New Brunswick, vol. iv, p; 
 
 atavus. 200, pi. ii, figs. 2, a to/. 
 
 A synopsis of the description of this species was published in the Bul- 
 letin of the Natural History Society of New Brunswick as above noted, 
 a fuller description is the following : 
 
 Shell substance thin, calcareo-corneous. Valves somewhat quadrately 
 oval to ovate ; rather strongly arched transversely and behind. 
 
 Ventral valve somewhat pointed behind and having an inconspicuous 
 umbo. Cardinal area very small and obscure, not more than one-seventh 
 of the length of the valve. No pedicle groove has been determined, but the 
 shell deepens suddenly in the interior behind the cardinal line. Except at 
 the umbo the margins of the shell are strongly arched down. The interior 
 shows at the side a pair of long lateral scars in the posterior half of the valve;: 
 extending from these scars forward are arching impressions of the vascular 
 trunks. The scars of the central muscles are in the front half of the valve. 
 
 The dorsal valve differs from the ventral in the rounded posterior end 
 and in the depressed longitudinal band which traverses the median part. 
 The interior has a rhombic depression at the back, on the sides of which 
 are placed the prints of a pair of muscle scars. Thence a narrow raised 
 band extends along the median line nearly to the front. On each side near 
 the middle of this band is a small muscle scar. Impressions of a vascu- 
 lar band extend along each side of the valve. 
 
 Sculpture. — Somewhat obscure, fine concentric strise, visible with a 
 lens, can be observed on all parts of the valve ; there are about 15 to 20 
 in the space of a millimetre. But a strong lens will hardly resolve the 
 finer ornamentation, which consists of a granulation, due to opposite 
 series of striae, crossing the shell diagonally. The second layer of the 
 shell is smooth and shining, but having concentric ridges similar to those 
 of the outer layer, without the minuter markings. Stronger growth 
 lines occur at intervals of 6 to 10 of the concentric ridges. 
 
 Size. — Length, 5 mm. ; width, 3J mm. ; depth, 1 mm. Young indi- 
 viduals are proportionately wider, because in the latei stages of growth 
 additions are made chiefly to the front of the valve. 
 
 Horizon and locality. — In assises E. 3 c? and e (Upper Etcheminian) 
 at Dugald brook, Escasonie, &c. 
 
107 
 
 The following table will show the size and salient characters of this 
 species. The second, third and fourth columns give the dimensions of 
 the valves ; the fifth column, the length of the callus, in front of or near 
 which the central muscles are placed ; the sixth column shows the dis- 
 tance from the umbo of the principal growth furrows on the outer sur- 
 face of the valve, which mark resting stashes in the growth of the shell, 
 the main furrow is usually at the front of the visceral cavity ; the 
 seventh column indicates the height of the hinge area ; and the eighth 
 column the space between the impressions of the vascular trunks. 
 
 Dimensions of Leptobolus atavus from Assise E. 3 e. 
 
 — 
 
 ll 
 
 g 
 
 1 
 
 1 
 
 
 Resting 
 Stages. 
 
 i 
 
 CO 
 
 
 
 
 
 mm. 
 
 mm. 
 
 mm. 
 
 mm. 
 
 mm. 
 
 mm. 
 
 mm. 
 
 
 r 
 
 1 
 
 5 
 
 3 
 
 
 
 24 34 
 
 
 24 
 
 Exterior ! exfol'd. 
 
 
 2 
 
 44 
 
 2| 
 
 
 
 34 
 
 
 2i 
 
 II soulp. oorrod. 
 
 i 
 
 3 
 
 5 
 
 3 
 
 
 2 
 
 4 
 
 ! 
 
 2 
 
 Interior. 
 
 1 
 
 4 
 
 5 
 
 3 
 
 
 
 34 
 
 1 
 
 2 
 
 ti 
 
 1 
 
 5 
 6 
 
 5 
 5 
 
 34 
 3 
 
 
 
 
 
 
 Exterior, sculp ! 
 
 1 
 
 2 
 
 34 4 
 
 
 Dimensions 
 
 II exfol'd. and features 
 
 
 
 of the valves 
 
 
 7 
 
 4 
 
 3i 
 
 
 
 34 
 
 4 
 
 
 II II widened, in assise B So 
 
 
 8 
 1 
 
 5 
 
 3 
 
 
 
 
 
 
 II sculp., corrod. 
 
 
 
 
 
 
 
 
 384 
 
 244 
 
 
 4 
 
 24 174 8 
 
 2 
 
 8| 
 
 
 
 4-8 
 
 S'l 
 
 
 2- 
 
 2-5,3-5,4 
 
 •7 
 
 2 2 
 
 Average. 
 
 ' 
 
 5i 
 
 3. 
 
 
 34? 
 
 34 
 
 
 
 Mould of inter, narrow ? 
 
 
 2 
 
 44 
 5 
 
 ,3 
 
 
 34 
 
 
 4 
 
 
 11 II broaden'd 
 
 i 
 
 3 
 
 3 
 
 
 344 
 
 
 Interior. 
 
 »■ 
 
 rS 
 
 4 
 
 44 
 4 
 
 24 
 2 
 
 
 34 
 24 
 
 24 34 
 
 
 
 Exterior, sculp ! 
 
 IS 
 
 • 
 5 
 
 i 
 
 4 
 
 14 
 
 Interior ! 
 
 i 
 
 6 
 
 54 
 5 
 
 34 
 3 
 
 
 Mould of exterior. 
 
 7 
 
 
 
 
 4 
 
 
 Exterior, sculp ! 
 
 . 
 
 8 
 
 4 
 
 24 
 
 
 3 ? 
 
 34 
 
 1 
 
 2i 
 
 2 
 
 Mould of interior. 
 
 
 38 
 
 224 
 
 71 
 
 16 
 
 2414 4 
 
 34 
 
 
 
 4.8 
 
 2-8 
 
 1- 
 
 3-2 
 
 2-5,3-5,4- 
 
 •6 
 
 17 
 
 Average. 
 
10,8 
 
 The variation in form shown above is largely the result of distortion in 
 the shells after they were imbedded. The following table shows the 
 form and other features of valves from the assise below. 
 
 Dimensions of Leptobolus atavus from Assise E. 3 d. 
 
 
 S 
 
 ^ 
 
 43 
 
 
 A 
 
 Crrowth 
 
 » 
 
 A 
 
 
 
 s 
 
 g 
 
 
 03 
 
 ^ 
 
 Groves. 
 
 CO 
 
 a 
 
 
 
 121 
 
 h! 
 
 P5 
 
 Q 
 
 Q 
 
 
 W 
 
 H 
 
 
 
 
 mm. 
 
 mm. 
 
 mm. 
 
 mm. 
 
 mm. 
 
 mm. 
 
 mm. 
 
 
 r 
 
 1 
 
 5* 
 
 3 
 
 1 
 
 
 345 
 
 1 
 
 2 
 
 Interior, mould, narrow 
 
 
 2 
 
 6 
 
 3 
 
 1 
 
 %h 
 
 4? 
 
 1 
 
 
 M • ir ir 
 
 ^ 
 
 3 
 
 6 
 
 3 
 
 1 
 
 
 34 5 
 3444 
 
 
 
 Exterior, corrod. narrow 
 Interior, mould. 
 
 IJ 
 
 4 
 
 5A 
 
 3 
 
 1 
 
 3? 
 
 1 
 
 2 
 
 c 
 
 5 
 
 fi' 
 
 3i 
 
 1 
 
 2? 
 
 34 
 
 
 
 IF II 
 
 > 
 
 Dimensions 
 
 and characters ^ 
 
 6 
 
 6 
 
 3 
 
 1 
 
 
 44 
 
 
 
 
 7 
 8 
 
 1 
 
 1 
 1 
 
 
 
 
 
 3 
 
 4 54 
 
 
 2i 
 
 II 11 
 
 •of the valves 
 in assise E id. 
 
 45i 
 
 25 
 
 1 
 
 104 
 
 22,244 
 
 3 
 
 6i 
 
 
 
 5-7 
 
 31 
 
 1 
 
 2-6 
 
 4-4,4-9 
 
 1 
 
 21 
 
 Average. 
 
 f 
 
 5A 
 
 3 
 
 1 
 
 4 
 
 4 
 
 1 
 
 al 
 
 Interior, mould, narrow 
 
 
 2 
 
 .-i 
 
 2f 
 
 1 
 
 
 4 
 
 1 
 
 
 II II II 
 
 A 
 
 3 
 
 5* 
 
 3i 
 
 1 
 
 4 
 
 34 44 
 
 1 
 
 24 
 
 M 
 
 1, 
 
 4 
 
 5 
 
 3 
 
 1 
 
 4 
 
 3 4 
 
 1 
 
 24 
 
 II mould 
 
 
 5 
 
 5 
 
 3 
 
 1 
 
 4 
 
 4 4^ 
 
 
 24 
 
 II M shortened 
 
 P 
 
 6 
 
 6 
 
 3 
 
 1 
 
 4 
 
 4 4J 
 
 i 
 
 
 Interior. 
 
 
 7 
 
 6 
 
 3 
 
 1 
 
 ^* 
 
 
 
 
 „ 
 
 
 8 
 
 44 
 
 2| 
 
 1 
 
 4 
 
 
 24 
 
 Exterior, sculp-corrod. 
 
 
 43i 
 
 25i 
 
 8 
 
 274 
 
 224,174 
 
 5 
 
 124 
 
 
 
 5-4 
 
 3-2 
 
 1 
 
 3-9 
 
 3-7 4 4 
 
 1 
 
 2-5 
 
 Average. 
 
 Compared 
 with other 
 species. 
 
 In this assise the valves are larger, and proportionately longer than in 
 Assise E. 3 e. 
 
 This species is of about the same size and geological age as LinguleUa 
 Jerrugmea, Salt.; but if Davidson's figures are correct, that species has a 
 hinge area twice as long as this. It may be further observed that David- 
 son has included in his species forms from much higher zones of the Cam- 
 brian (Dolgelly Group, <fec), but the characters are so vague, that any small 
 oval species may be referred to L. ferruginea. We are subject to the 
 dilemma of chosing between two, or several species which by form and size 
 represent the species named, hence if one is L. ferruginea the others are 
 not. 
 
 LinguleUa Grcmvillensis, Walcott, of the New York Cambrian, is of 
 about the same size as this, and approaches it in form, but the moulding 
 of the interior of the dorsal valve differs. 
 
109 
 
 Mr. Walcott has borrowed from the writer the types of this species 
 and of Lingulepis Gregwa for study and has decided that the former is 
 the young of the latter.* While having the highest respect for Mr. Wal- Not the young; 
 cott s knowledge of (Jambrian Brachiopoda, it may be well to present Gregwa. 
 certain objections to this dictum. 
 
 StudiBnts of the Brachiopoda will recognize that in Lingulella and allied 
 generisi the young stages are often round, when the adults become elon- 
 gated by more rapid growth at the front than at the sides. In assuming 
 Leptoholus atavus to be the young of Lingulepis Gregwa Mr. Walcott 
 would reverse this law. Another objection to this decision is that L. 
 Gregwa does not occur in the Assises E. 3 c? and E. 3 e, where L. atavus 
 is found but is much older ; and on the other hand L. atavus in the typical 
 form does not occur in the (Assise E. 1 d,) Gregwa shale. Other objections 
 might be pifesented, but these are sufficient. 
 
 Mutation teitavus, n. mut. PI. VI, figs. 5 a-c. 
 In the Lower Etcheminian another form which may be referred to this ,, , ,. 
 
 •' . Mutatiom 
 
 species is found. It is smaller than L. atavus or L. insulce but propor- tritavus. 
 
 tionately wider j the edges of the valves have a radiating as well as con- 
 centric ridging. 
 
 The following are the dimensions of some valves collected. 
 
 Dimensions of Leptobolus m. tritavus from Assise E. 1 d. 
 
 — 
 
 4. 
 
 •B 
 
 1 
 
 t 
 
 1 
 
 Growth 
 Grooves 
 
 w 
 
 i 
 
 a 
 
 
 
 
 1 
 
 2 
 3 
 
 mm. 
 
 4 
 4 
 34? 
 
 mm. 
 
 mm. 
 
 1 
 1 
 1 
 
 mm. 
 
 2? 
 
 ii 
 
 mm. 
 34 " 
 
 mm. 
 ■ 1 
 
 mm. 
 
 l| 
 14 
 
 Interior, mould. 
 
 1 
 
 
 
 
 Interior. 
 
 
 114 
 
 7J 
 
 3 
 
 7 
 
 34 
 
 1 
 
 41 
 
 
 3-8 
 
 2-4 
 
 1- 
 
 2-3 
 
 3-5 
 
 1 
 
 1-5 
 
 Average. 
 
 03 
 
 1 
 2 
 3 
 
 4 
 4 
 4 
 
 24 
 
 24 
 
 2|. 
 
 1 
 
 1 
 1 
 
 24? 
 
 243 
 li 3i 
 
 ■■■4?' 
 
 "14? 
 
 Interior. 
 Interior, mould. 
 
 « 
 
 
 
 
 Q 
 
 
 12 
 
 74 
 
 3 
 
 24? 
 
 IS 24 6i 
 
 4? 
 
 14? 
 
 
 
 (. 
 
 4- 
 
 2-5 
 
 1 
 
 24? 
 
 1-7 2-5 3-1 
 
 ■5? 
 
 1-5? 
 
 Average. 
 
 Dimensions 
 &c, of this 
 form. 
 
 *Proeed. U.S. Nat. Mus. vol. XXIII, page 694. 
 
no 
 
 Mutation 
 inhulae. 
 
 Leptobolus atavus, tnut. insula, n. sp. Plate VI, figs. 4, a — c. 
 
 Minute, shell thin, corneous or calcareo-corneous. Valves deep, elongate 
 oval, having the edges rolled back. Ventral valve more pointed than the 
 dorsal, having a small cardinal area where the shell is thickened, about 
 one-tenth of ihe length of the valve. Interior. — There is a lenticular 
 cavity just in front of the hinge line. Visceral callus extending nearly 
 to the middle of the valve ; a faint transverse swelling is seen on some 
 valves, half way from the beak. Grooves, that appear to be due 
 to vascular trunks, but run along near the lateral margins of the valve. 
 The dorsal valve approaches an elliptical form. It has a short area, 
 with a tubercle on the axial line. Interior. — In front of the area is a 
 transverse depression in which on each side is a pit, apparently for the 
 attachment of the posterior adductors. The depression merges on each 
 side into long, narrow lateral grooves (for vascular trunks ?) like those of 
 the ventral valve. The visceral callus extends across the middle third of 
 the valve, where also on the axial line are low septal ridges. 
 
 Sculpture. This species has fine strise, concentric to the umbo, over 
 the whole shell. 
 
 Size. Length of ventral valve, 4^ mm. 
 mm. shorter. 
 
 Compared to 
 
 Lingialella 
 
 linguloides. 
 
 width 2| mm. ; the dorsal is \ 
 
 Horizon andlocality. Assise E. 2, {a V) Lower Btcheminian at Young's 
 Point. George R. Station, N. S. Scarce. 
 
 This form is of about the same length as Lingulella linguloides of the St. 
 John terrane in New Brunswick (which also appears to be a Leptobolus), 
 but is proportionately narrower ; it also resembles L. atavus of the 
 Upper Etcheminian Fauna in form, but is considerably smaller and nar- 
 rower and the callus of the ventral valve is proportionately shorter. 
 The shell is very thin, and is flexible, as its valves are more distorted 
 than those of the Lingulellas with which it is associated, and it is often 
 moulded on the grains of sand with which it is imbeded. When the 
 shell is distorted diagonally it may be mistaken for a small Ostracod, 
 owing to the vascular groove which gives the margin the appear- 
 ance of having a marginal fold, so often found in this group of crus- 
 taceans. 
 
 The following are dimensions of the valves of this mutation. 
 
Ill 
 
 Dimensions of valve of Leptobolus (mut.) insula. From assise E. 2 (a?). 
 
 
 No. 
 
 1 
 2 
 3 
 4 
 5 
 6 
 
 1 
 2 
 3 
 4 
 5 
 6 
 
 Length. 
 
 Width. 
 
 Callus. 
 
 Growth of 
 Groove. 
 
 Hinge. 
 
 Trunks. 
 
 
 r 
 
 mm. 
 44 
 44 
 4 
 4 
 4 
 4 
 
 mm. 
 
 2I 
 
 2 
 2 
 
 mm. 
 24 
 
 mm. 
 
 mm. 
 
 mm. 
 
 
 
 H 
 
 
 
 
 V 
 
 
 
 ir 
 
 i 
 
 2i 
 
 3 
 
 2| 
 
 4 
 
 2 
 
 II M 
 
 
 
 
 d 
 
 
 
 
 
 
 
 25 
 
 14 
 
 4i 
 
 9 
 
 4 
 
 2 
 
 
 t> ^^ 
 
 4-2 
 
 f 
 
 4 
 
 3 
 
 3 
 
 34 
 
 23 
 
 2-4 
 
 3 
 
 0-5 
 
 2 
 
 Average. 
 
 
 1 
 
 2 
 
 2 
 
 2 
 
 If 
 
 
 2-3 
 
 
 
 
 
 
 
 
 s 
 
 2| 
 
 3 
 
 
 
 II exterior. 
 
 > 
 
 
 
 ti interior. 
 
 ti 
 
 
 
 
 
 
 24 
 
 
 
 
 Mould of interior. 
 
 £ 
 
 21i 
 
 13i 
 
 5i 
 
 2-6 
 
 
 
 
 
 
 
 
 3-6 
 
 2-2 
 
 2-6 
 
 2—3 
 
 
 
 Average. 
 
 
 
 
 Dimensions 
 &c. of this 
 form. 
 
 A comparison of the size and form of Leptobolus in the most typical 
 group, gives interesting results. It shows a development in these Basal 
 Cambrian rocks by an increase of the valves both in length and breadth, 
 ■which is parallel to the development of Acrotreta in the Cambrian 
 rocks, as a whole, as shown above, and in the writers paper on the Cam- 
 brian AcrotrotidsB, etc.* This will be seen by the following table in 
 which only the ventral valves' are considered. 
 
 Development of the phylum of Leptobolus atavus in the Basal Cam- 
 brian rocks. 
 
 Assise Co., homogeneous fine gray shale, L. torrentis. 
 
 Assise E. Id, shale with volcanic sand, uniform 
 marine current, atav-us, mut. tritavus 
 
 Assise E. 2 (a ?) sandy shale, marine currents oon- 
 flictiiig, atavus mut. insulw 
 
 Assise E. 3d, homogeneous gray shale, marine cur- 
 rent uniform, L. atavus . . 
 
 Assise E. 3e flaggy, more^silioious shale, marine cur- 
 rent uniform, L, atavus 
 
 Length. 
 
 mm. 
 30 
 
 3 
 
 4 
 5 
 4 
 
 Width. 
 
 mm. 
 20 
 
 2-4 
 
 2-3 
 
 1 
 
 1 
 
 Propor- 
 tion. 
 
 1-5 
 
 1-6 
 
 1-8 
 
 1-84 
 
 1-55 
 
 Area. 
 
 60 
 
 Development 
 9 1 of the phylum 
 
 of Leptobolus 
 9 ' 7 atavus. 
 
 17-7 
 
 14-9 
 
 * Additional notes on the Cambrian of Cape Breton, etc. Bull. Nat. Hist. Soc, N.B., 
 vol. iv, p. 377, etc. 
 
112 
 
 Of these five horizons, one is in the Cold brook terrane, two in the 
 Lower and two in the Upper Etchiminian faunal zones, and the gradual 
 increase in size is quite noticeable. As far as the assise E. 3 d, there is a. 
 regular increase in the proportionate length of the valv.es, as compared 
 with their width. But the return to flaggy and silicious beds reduces 
 both the length and the superficial- area of the valves. The layers of E. 
 3 e are crowded with multitudes of -these little shells, which make up in 
 numbers what they lack in size ; while in the sandy layers of E. 2 (as ?} 
 the shells of this genus are scarce ; and notwithstanding the coarseness 
 of the matrix are thin. 
 
 Leptobolus collicia, pi. VI, figs. 3 a — e. 
 
 Leptobolus (?) collicia. Bull. Nat. Hist. Soc. N.B., vol. iv, p. 200, pi. i, figs. 3, a—e. 
 
 Leptobolus A small oval species somewhat pointed in front. Margins flattened, 
 
 especially in the posterior half. Remarkable for the peculiar spoutlike 
 flexure at the front of the dorsal valve, acquired in the later stages of 
 growth. A corresponding pair of grooves appears in the anterior part of 
 the ventral valve. 
 
 Sculpture. This consists of fine concentric ridges, visible only with the 
 aid of a lens. These sometimes anastomose. 
 
 Size. — Length 10 mm., width 6 mm. 
 
 The peculiarity from which the name of this species was taken has 
 been found to be a sporadic character ; many valves do not have it. 
 
 The examples of this species first obtained, did not show clearly some 
 of the essential characters of Leptobolus and the generic reference was 
 left open. Examples obtained since IJhen show that the conjectural 
 generic reference was a right one : such as the forward position of the 
 muscular scars and the grooves near the margin, supposed to be due to 
 vascular trunks : this added to the regular oval form, fine sculpture, low 
 hinge area, and similarity of the umbones of the two valves, are fair 
 characters of Leptobolus. 
 
 Characters of Leptobolus collicia was a small species (though large for the genus), 
 e species. moderately tumid, oval, but somewhat pointed inf ront ; margins flattened 
 somewhat in the posterior half. 
 
 The ventral valve is pointed at the umbo, and has a very narrow apical 
 slit or groove ; it is evenly sloped to the margins, and, for a Leptobolus, 
 rather flatly arched. There are two furrows or a depressed area in some 
 examples, at the front of the valve. Interior. The callus is quite narrow, 
 subtriangular, and about three-sevenths of the length of the valve. The 
 lateral septa extend nearly half of the valve ; they reach beyond the callus. 
 
113 
 
 The dorsal valve is oval in form, and has a somewhat depressed band 
 along the middle, for' most of its length, but otherwise it is evenly slbped 
 down to the margin ; some examples are elevated along the middle in the 
 interior quarter of the valve, forming a kind of spout at the front. The 
 interior has a median band or callus extending three quarters of the 
 length of the valve, and the lateral septa extend two thirds of its length; 
 the marginal grooves (vascular trunks 1) also show along this portion of 
 the valve, and in front of it are forked. There are several fine ridges 
 close together, along the median band, the two outer of which end at the 
 mid-length of the valve. 
 
 Sculpture. — This, as mentioned in the original description, is of fine 
 concentric ridges, of which there are about fifteen in the space of one 
 millimetre ; some examples have as many as twenty to a millimetre on the 
 sides of the valves ; these are crossed by close-set, minute, less conspicu- 
 ous radiating atrise, that give a beaded appearance to the edges of the 
 concentric ridges ; there are also a number of growth grooves, marking 
 resting stages in the growth of the valve. 
 
 Size. — Length 10 mm.; width 6 mm.; depth of each valve about 1 mm. 
 
 ■ Horizon and locality. — In Assises E. 3 c, and e. Upper Etcbeminian, 
 at Dugald brook, and f, at Gillis' Indian brook, Escasonie, N.S. 
 
 The following are characters of the valves from the three horizons : 
 Valves of Leptobolus coUicia from E. 3 e. 
 
 ra I 
 
 > L 
 
 s f 
 
 i 
 
 .a 
 
 a 
 1 
 
 1 
 
 2 
 8 
 
 1 
 2 
 3 
 
 4 
 
 i 
 § 
 
 Hi 
 
 1 
 
 
 
 w 
 
 1 
 
 6 + 
 
 n 
 
 4 
 
 3 
 
 44 
 
 
 
 
 
 34 
 
 4 6 
 
 
 
 20 
 60 
 
 13 
 
 6J 
 
 84,5 
 
 
 
 4-2 
 
 3-2 
 
 4-2,5 
 
 
 
 
 
 6 
 
 
 4 
 4 
 4 
 4 
 
 3 
 
 4 
 
 34 
 
 4 
 
 '4' 
 
 44 
 4 
 
 1? 
 
 1 
 1 
 4+ 
 
 ■'3' 
 ■3' 
 
 m 
 
 16 
 
 144 
 
 124 
 
 34 
 
 6 
 3 
 
 61 
 
 40 
 
 3-6 
 
 41 
 
 0-9 
 
 Interior. 
 
 No. 2 has closely set faint striae ; two faint ridges 
 
 from the callus to the front margin. It is 
 
 shortened by pressure. 
 No. 3 is lengthened by pressure. 
 
 Average. 
 
 No. 1 shows very fine strise 20 to 1 mm. 
 
 No. 2 mould of interior, shows callous and trunks. 
 
 No. 3 elongated, mould, shows callus. 
 
 No. 4 mould of interior. 
 
 Average. 
 
 Dimensions 
 &c. of valves 
 in assise E 3e. 
 
 8— C. R. 
 
lU 
 
 Dimensions 
 &o. of valves 
 in assise e So. 
 
 Dimensions • 
 &o. of valves 
 in the assise 
 e3/. 
 
 Valves of Leptobolus coUioia from E. 3 c. 
 
 — 
 
 1 
 
 p 
 
 ;?; 
 
 1 
 
 2 
 
 3 
 4 
 
 1 
 
 2 
 
 3 
 4 
 5 
 
 1 
 
 8 
 8 
 
 7 
 8 
 
 4 
 
 •a 
 5 
 
 1 
 
 ^1 
 
 1 
 
 .1 
 
 
 ,< 
 
 Si 
 
 3? 
 
 6 
 6 
 
 4 
 
 3 
 
 Interior and mould of same. 
 
 No. 2. Sculpture of fine concentric ridges. Fine 
 
 11 
 
 '1 + 
 
 
 growth lines at intervals. 
 No. 3. Interior shows median sulcus at front. 
 No. 4. Mould of interior. 
 
 
 31 
 
 20 
 
 6i 
 
 12 
 
 2i 
 
 3 
 
 
 
 7-7 
 
 50 
 
 31 
 
 6 
 
 1-3 
 
 3 
 
 Average. 
 
 fl 
 
 7 
 
 7 + 
 
 6i+ 
 
 7 
 
 T 
 
 5 
 
 4 
 
 5+ 
 
 5 
 
 5 
 
 1 
 
 1 
 
 1 
 1 
 
 1 
 
 
 Mould, masoerated and wrinkled. 
 No. 2. Hinge and visceral callus distinct. 
 Sculpture, fine rather distant ridgts. 
 
 No. 4. Mould shows cardinal area. 
 
 No. 5 shows spout, visceral callus and hinge area. 
 
 
 35 
 
 24 
 
 23 
 
 5 
 
 5 
 
 
 
 
 70 
 
 4-8 
 
 4-6 
 
 5 
 
 10 
 
 
 Average. 
 
 Valves of Leptobolus collioia from Assise E. 3 /. 
 
 — 
 
 1 
 
 i 
 
 s 
 
 Hi 
 
 4 
 
 ■a 
 
 
 .^1 
 
 S to 
 
 s 
 
 1 
 
 
 1- 
 
 > 
 
 1 
 
 2 
 3 
 4 
 5 
 6 
 
 1 
 
 f 
 
 7 
 6 
 6i 
 
 74 
 
 i 
 4 
 
 
 
 
 Surface corroded. 
 
 3' 
 34 
 
 ■"■44 
 
 
 '24 
 ■24 
 
 Interior, callus has three ridges. 
 Obscure sculpture. 
 
 Interior, callus and trunks. 
 
 
 374 
 6-6 
 
 244 
 41 
 
 64 
 3 2 
 
 44 
 
 
 5 
 
 
 
 4-5 
 
 
 2-5 
 
 
 ■i 
 
 7 
 
 4 
 
 4 
 
 6 
 
 1 
 
 24 
 
 Surface corroded. 
 
 Var., COLLI8, n. var. 
 
 Variety collis. This is distinguished by its larger, broader and flatter valves. The 
 dorsal valve has a longer callus ; while, differing from the type, the lateral 
 septa do not extend as far forward as the callus. 
 
115 . 
 
 Sculpture. — Owing to the coarseness of the matrix, and the corrosion of 
 the surface in the examples known, the ornamentation is very imperfectly 
 preserved. Some examples show obscurely a fine concentric ridging ; 
 these ridges are much more numerous than those of Lingvlella longovalis 
 of the Lower Etcheminian Fauna which this somewhat resembles n form. 
 
 Size. — Length of the ventral valves 8^ mm. ; width 5J- mm ; the 
 dorsal is about 1 mm. shorter. 
 
 Horizon and locality. — Bandy gray shales of Assise E. 3/. at Gillis- 
 Tndian brook. 
 
 The following table will show the size and variation in form of a 
 number of valves : — 
 
 Valves of Var. Leptobolus coUis in Assise E. ZJ. 
 
 •3-! 
 
 _i 
 
 774 
 7-7 
 
 7 
 7 
 6 
 7 
 7 
 64 
 64 
 6+ 
 6 
 7 
 
 66 
 
 6-6 
 
 54 
 
 O 
 
 Resting 
 stages of 
 growth.* 
 
 524 
 
 5-2 
 
 26 
 
 3-7 
 
 49 
 
 4-9 
 
 22 
 
 4-4 
 
 54 
 54 
 44 
 
 6i 
 
 bo 
 bo 
 
 in 
 
 39 13 
 
 5-6 6-5 
 
 304 
 
 
 4i 
 
 20 
 2-9 
 
 12 
 
 The dimensions given in this table are in 
 millimetres. 
 
 No. 1 shows several retting stages in the 
 
 pedicle groove as well as on the outside 
 
 of the shell. 
 No. 2 and No. 1 on the same slab have been 
 
 differently distorted owing to difference 
 
 in the orientation of the valves. 
 No. 4 is narrowed by distortion. 
 No. 6 elongated, shows vascular trunks 
 
 well. 
 No. 8 sculpture of fine concentric beaded 
 
 No. 9 bf-oadened. leptobolus 
 
 No. 10 shows traces of pedicle at pedicle coJIieia-coUis. 
 groove. 
 
 Average. 
 
 No. 1 masceiated and wrinkled. 
 
 No. 2 sculpture very fine beaded ridges. 
 
 No. 4 interior, shows muscle scars. 
 
 No. 8 broadened, mould of interior. 
 
 No. 9 
 
 No. 10 11 mould of interior. 
 
 Average. 
 
 *The distance of each main cicatrice or resting stage, from the umbo, on the 
 median line, is recorded in this and the following tables. 
 ^—C. E. 
 
116 
 
 LINGULELLA, Salter, 1861* 
 
 Characters of When first studying LinguleUa SeUvyni, with much more defective mate- 
 ingu e a. ^.^^ than has since been obtained,** it had seemed to the writer that 
 there was a close relationship between the Russian species 0. Quenstedti 
 and species of the genus LinguleUa. Messrs. Hall and Clarke had 
 noticed the same.f Since then Michwitz has identified 0. Quenstedti 
 with 0. ApoUonis, the type of the genus Obolus, as a variety. | At a 
 still later date, Director Walcott, of the U, S. Geological Survey, has 
 followed up this line of investigation and has referred all Lingulellas to 
 Obolus, as belonging to a subgenus of the latter. ft 
 
 In support of this view, Mr. Walcott has marshalled much new evid- 
 ence showing the close alliance between these two genera, but still to the 
 writer there are objections to fusing the two. In the following descrip- 
 tion of the characteristics of L. Seluyyni more complete than was possible 
 a few years ago, some of these differences will appear, and this is a species 
 desirable to use in this way, as it is particularly oboloid in aspect, from 
 its broad cardinal area in the dorsal, its depressed beak, and other 
 features. The horizon to which it belongs is far below that assigned to 
 L. Daviaii, the type of the genus LinguleUa, and if one may judge by 
 Salter's description of that species, this was smaller and deeper in the 
 valves. 
 
 The types of Brachiopods which the writer in former articles has referred 
 to LinguleUa, in this report, he has divided into three groups LinguleUa, 
 Salter Lingulepis, Hall, and Leptobolus, Hall. The characters under 
 which the two latterare separated are described under the two genera named 
 and need not here be repeated or anticipated. Species, however, still remain 
 under LinguleUa, which are closely related to one or other of the above 
 two genera (or sub-genera), that do not fully embody all the characters 
 assigned to those two genera. Such forms are here still retained under 
 LinguleUa. 
 
 LlNQULELLA SeLWYNI PL VII, figS. lo-C. 
 
 Linguella Selwyni, n. sp. Trans. Roy. Soc. Can. 2d ser. vol. 1, pi. i, figs. 1 
 a and b. 
 
 *In Memoirs Geolog. Surv. of G. Britain, vol. iii, 1880, p. 537, this genus appears to be 
 accredited to S. Woodward, by Salter. 
 + Genera Palseozoio Brachiopoda, p. 337, figs. 38 and 39. 
 JMem. Imp. Acad. Sci. St. Petersb. Ser. 8, vol iv, No. 2, p. 79. 
 **TranB. Roy. Soo. Can., 2ud Ser., vol. i, sec. iv., p. 256. 
 ttProo. U. S. Nat. Mus., p. 390. 
 
117 
 
 To show the anatomy of L. Selwyni the following figures have been Lingulella 
 drawn, enlarged four diameters from the original types. The pore pits 
 with which the shells are studded and the radiating pits of the mantle rays 
 are omited for greater clearness, but they are quite conspicuous on the 
 valves. 
 
 Lingulella Selwyni, enlarged 4 diameters to show musculation &c. 
 
 a Pedicle groove — 6, pseudo-deltidium — c, cardinal area — d, excurrent 
 branches of the circulatory system — e, front of the brachial area — f, 
 small tubercles — g, cardinal muscle— ? — h, anterior adductors ("central ") 
 muscle — i, transmedian muscles — j, anterior laterals — k, interior laterals 
 — I, exterior laterals — p, pedicle muscle ? — v.t., vascular trunks — v.b., 
 branches of the vascular trunks. 
 
 VENTRAL VALVE. 
 
 Cardinal area. — This species has a well developed pedicle groove 
 in the ventral valve, with slopes on each side descending to the deepened 
 central depression, or groove. The pseudo-deltidium is rather narrow, 
 and its sides slope inward as above described, the areal borders are nar- 
 row, and the strise diagonal. The beak is depressed. 
 
 The strise on the cardinal area cannot be due to the contact of the 
 valves in this part as when fully grown the strise of the last growth in 
 the shell are depressed from J to 1 mm. below l^e plane of the edge of 
 the valve, and the corresponding depression on the dorsal valve would 
 leave these two valves nearly two millimetres apart at the back, hence 
 it seems probable that a ligamental (ileoparietal) band connected the 
 
118 
 
 two and gave rise to the striae that traverse this portion of the margin 
 of the valves. If so, the valves of Lingulella may have had much less 
 mobility than those of Lingula, and perhaps a diflerent interpretation 
 should be given to some of the muscle soars of Lingulella whose office 
 and use are based on supposed analogues in the living genus Lingula. 
 
 Muscular Muscle Scars. Cardinal and pedicle muscles. There is great difficulty 
 
 venS valve. ^'^ recognizing the imprint of the cardinal muscles ; in a few valves very 
 shallow round pits (g) on each side within the visceral cavity appear to 
 represent the cardinal muscles. A little in front of the cardinal muscles 
 on the median line, is a small lozenge shaped depression, which is separated 
 by a low elevation from a small round pit, also on the median line, this 
 pit (p) perhaps marks the point of attachment of the sinews of the ped- 
 icle muscle. From this small depression the thickened visceral callus, 
 occupying the middle third of the valve, extends forward to the central 
 group of muscles. 
 
 Centrals — These form, on each side of the front of the callus, a trian- 
 gular group, consisting in each of a large posterior triangular print (h), 
 and two smaller anterior muscles ; of these the outer Q) is a narrow trans- 
 verse triangular scar with the acute point of the triangle turned inward ; 
 the inner print (A) is rounder than the outer and somewhat posterior to 
 it; it is obscure. 
 
 Laterals — Two lateral muscle scars are imprinted at the side of the 
 valve, near the hinge area. Of these the posterior and smaller, though 
 outer (i) in the ventral valve, is supposed to mark the place of a trans- 
 median muscle, the anterior and large (_;), is the principal lateral muscle 
 (unless the office of these two muscles is reversed). 
 
 Circulatory The vascular system — Along the lateral margin in the posterior half of 
 
 system. the shell, the imprint of the vascular trunks is straight; they diverge 
 
 considerably and throw off numerous branches toward the margin of the 
 valve. At the mid-length of the valve the trunks begin to converge, and 
 on the outside throw oflf a few short branches, directed forward. On the 
 inside of the trunks the branches are numerous ; at first they are trans- 
 verse, but farther forward the branches, especially in the central space, 
 turn forward toward the opening between the extremities of the main 
 vascular trunks. 
 
 Dorsal Valve. 
 
 Cardinal area. — This is unusually wide for a Lingulella, and is dis- 
 tinctly striated transversely, the striae arching forward in the middle; the 
 areal borders are narrow and mark a change in the course of the striae 
 that traverse the back edge of the valve. A slightly raised ridge, like 
 
119 
 
 a orescent, marks the division between the cardinal area and the visceral Muscular 
 cavity. The middle of the cardinal area, at the hinge line, is three J^^gi valve. 
 quarters of a millimetre be'ow the sides, showing a depression here, as in 
 the ventral valve, but much wider. 
 
 Muscle soars. Cardinal. — Though there is a general depression at the 
 back of the valve in front of the cardinal area, there is nothing which 
 can with any certainty, be regarded as the imprint of a cardinal muscle. 
 But there is a pair of narrow scars outside of and behind the group of 
 lateral muscles that may have some office in connection with the hinge. 
 
 Centrals. — The group of central muscles is strongly marked and is 
 situated at the middle of the valve. The centrals or anterior adductors, 
 (h) are oval in form, and about as far apart as the width of the cardinal 
 area. The anterior laterals (j) are about as far in front of the centrals 
 as these are apart ; they also are oval; are smaller and are closer together 
 than the centrals. Between the two pairs of muscle scars of the central 
 group, along the median line runs a sharp medium septum, with a narrow 
 furrow on each side of it ; in front of the anterior lateral scars the sep- 
 tum is replaced by a furrow. 
 
 Laterals. — At the back of the dorsal valve is a kind of angulated cres- 
 cent, between which and the posterior end of the vascular trunks, the 
 group of lateral scars are crowded together. On the line of the crescent 
 on each side is a heavy oval scar (i) ; behind and outside of this is a 
 small narrow scar supposed to be lateral (or cardinal) ; in front of 
 this is a large scar, which like the one on the crescent is usually well 
 defined, this is supposed to be the (Z) lateral ; an unimportant scar in 
 front of this, which is sometimes seen is also supposed to be a lateral (A). 
 
 The vascular system. — The main trunks in this valve are farther apart Circulatory 
 than in the ventral and more strongly arched. The branches also are 
 quite different in their course, etc. ; the main interior branches are 
 directed toward the central group of muscle-scars, and the outer ones 
 radiate regularly toward the margin of the valve ; the posterior inner 
 branches throw off several spurs each, on the posterior side. 
 
 Both valves have sinuses in the visceral cavity, those in the ventral 
 narrow and angular, those in the dorsal broader, and rounded behind. 
 
 That there are important differences between Obolus and Lingulella 
 will be seen from a comparison of the diagram of 0. Quenstedti given by 
 Michwitz with that of L. Selwyni as given above ; these may be tabulated 
 as follows : — 
 
120 
 
 This species 
 compared 
 with 0. 
 Quenstedti. 
 
 Ventral Valve. 
 
 Pedicle scar, relative to the cardinal muscle 
 
 Transmedian scar 
 
 Lateral mnscle ( j ) 
 
 Heartshaped area 
 
 Lateral muscle ( 1 ) relative to central (h) 
 
 Vascular branches 
 
 Vascular anterior, external branches directed 
 
 Dorsal Valve. 
 
 Posterior lateral ( 1 ) 
 
 Position of central muscle (h) in the valve 
 
 Anterior lateral ( j ) — from the front of the valves 
 
 0. Quenstedti. 
 
 Opposite. 
 
 Interior. 
 
 Exterior. 
 
 Present. 
 
 Lateral. 
 
 Sparse. 
 
 Outward. 
 
 Medium. 
 Middle. 
 One-fit th. 
 
 L. Selwyni. 
 
 Interior. 
 
 Exterior. 
 
 Interior. 
 
 Obscure. 
 
 Anterior. 
 
 Numerous. 
 
 Forward. 
 
 Lar^e. 
 
 Behmd middle 
 Two-fifths. 
 
 There may be some question as to the interpretation of the muscle 
 scars of the dorsal valve of Lingulella Selwyni given in the preceding 
 description, which is based on that of Lingula. But if it be assumed 
 that the three principal posterior scars of the dorsal valve represent 
 respectively i, I and k, the two latter will closely accord with those of 
 Obolus ; but then the poslerior outer scar is without analogy in that 
 genus, and the whole group is more closely crowded together. 
 
 Another distinction which appears to be of generic value is the position 
 of the (Z) lateral in the ventral valve. In 0. Quenstedti it is at the side 
 of the central scar (A), whereas in L. Selvn/ni it is at the front of this 
 scar. In consequence of the diflferent arrangement of the group of central 
 scars in this valve in Obolus, the front outline of these scars curves away 
 backward from the front of the visceral callus on each side, but in Lin- 
 gulella it is transverse, or even turns forward from the front of the callus. 
 It results that the whole group of central muscles in Lingulella is strongly 
 triangular. 
 
 The following is the original description of this species quoted from 
 Trans. Roy. Soc. Can. 2d Ser. vol I, Sec. IV. p. 255, pi. I, figs, la and b. 
 
 Original 
 description of 
 L. Selwyni. 
 
 "Lingulella Selwyni, n. sp., PI. J, Fig la and b. 
 
 The form is sub-ovate, broadly rounded in front, but having nearly 
 straight sides in the posterior half ; the beak of the ventral valve is regu- 
 larly pointed and that of the dorsal bluntly rounded. The ventral valve 
 in its interior, exhibits two large, triangular scars, where the central 
 muscles were attached, one on each side of the rhombic pit in the pos- 
 terior third of the valve. The posterior adductors appear on each side 
 of the hinge area, and there are sliding muscles, exterior to and in front 
 
121 
 
 of them. In front of the posterior adductor muscle on each side of the 
 •valve, there is a low ridge extending forward as far as the scars of the 
 ■central muscles : at and in front of these ridges the imprint of the main 
 vascular trunks is visible, extending forward toward the median line. 
 
 The interior of the dorsal valve has a broad scar (posterior adductor 1) 
 just in front of the striated hinge area, and on each side of the hinge are 
 impressions of sliding muscles. The central muscles are indicated by a 
 group of small pits near the centre of the valve ; of these the anterior 
 adductors are oval and somewhat apart at the mid-length of the valve ; 
 the anterior adjusters are indicated by a pair of small rounded pits, a 
 little in advance of those last named and closer together. A faint line 
 (indicating the border of the splanchnocoele ?) includes these scars and 
 runs back towards the posterior part of the valve. Extending forward 
 from near the cardinal area on each side are the lateral ridges and the 
 imprint of the vascular trunks, as in the ventral valve, but here more 
 distinct and bearing a number of branches directed, some inward and 
 some outward. 
 
 Sculpture. — -The external surface of the valve of this species is marked 
 by fine concentric lines, and fainter radiating lines ; there are also at 
 intervals, concentric growth lines, and less distinct undulations of the 
 shell, radiating from the umbo. 
 
 Size. — Dorsal valve. Length and breadth, each about 11 mm. The 
 •ventral valve is about 1-5 mm. longer. 
 
 Locality. — McFee's point, {i. e. Young point) George river. Cape 
 Breton ; collected by Messrs. Weston and Robert, of the Canadian Geo- 
 logical Survey. 
 
 The plan of the muscular scars of this species is very nearly that of 
 Oholus Quenstedti of A. Michwitz, found in Esthonia, Russit, and as we 
 find a shell in the Lower Cambrian of the St. John Group which possesses 
 all the essential characters of an Obolus, but differs from this shell, we 
 fully agree with Messrs. Hall and Clarke that 0. Quenstedti could, with 
 propriety, be excluded from Obolus ; whether it should go into Lingulella 
 will be better known when the internal features of the species L. Davisii, 
 the type of that genus, are more fully described." 
 
 Additional note on L. Selwyni. 
 
 A comparison of the size and outlines of the valves of this species Additional 
 shows it to have been a wide one. The vascular trunks of the ventral Lingulella 
 valve are half as far apart as the width of that valve. This species has Selwyni. 
 marked growth grooves on the outer surface, always outside of the 
 
122 
 
 visceral callus, and most numerous on the ventral valve. The dorsal 
 valve shows three grooves at an earlier stage than the ventral, but in the 
 latter the grooves are more numerous and are most abundant toward the 
 anterior margin ; there are perhaps one-half more of these grooves on 
 the ventral than on the dorsal valve ; for often there is only one, and 
 rarely more than two on this, but frequently three on the ventral. The 
 following table shows the relation of these grooves to the length of the- 
 shell. 
 
 Valves of L. Selwyni from Assise B. 1 (a T) 
 (The dunensions given are in millimetreB.) 
 
 Ventral. 
 
 Dorsal. 
 
 1 
 
 4 
 
 h! 
 
 12 
 
 12 
 
 15 
 
 10 
 
 12 
 
 13 
 
 14 
 
 13 
 
 124 
 
 124 
 
 12 
 
 138 
 
 12-5 
 
 4 
 
 •73 
 
 13 
 13 
 13 
 14 
 13 
 
 114 
 104 
 
 12 
 11 
 10 
 11 
 132 
 12 
 
 i 
 
 5 
 5 
 7 
 
 44 
 
 5 
 
 44 
 
 Besting Stages 
 of Growth. 
 
 C3 
 
 1 
 
 1 
 
 1 
 2 
 3 
 4 
 5 
 6 
 7 
 8 
 
 . 9 
 10 
 11 
 
 4 
 
 of) 
 
 g 
 
 lOi 
 13 
 12 
 12 
 14 
 11 
 10 
 
 11 
 9 
 
 114 
 
 9 
 123 
 11- 
 
 4 
 
 •a 
 
 12 
 
 144 
 
 11 
 
 13 
 
 13 
 
 10 
 
 10 
 
 12 
 
 9 
 
 10 
 
 9 
 
 1234 
 
 11- 
 
 4 
 1 
 
 ^ 
 
 be 
 1 
 
 i 
 
 3 
 
 Kesting Stages 
 of growth. 
 
 1 
 
 6 
 64 
 
 7 
 64 
 
 8 
 9 
 
 8 
 
 8 
 
 8 
 
 84 
 
 494 
 8-2 
 
 11 
 10 
 
 
 6 
 
 64 
 
 7 
 
 
 
 74 
 
 8 
 8 
 8 
 
 
 2 
 
 
 
 11 
 
 3 
 
 
 6 
 
 
 
 Dimensions of 
 L. Selwyni. ^ 
 
 5 
 
 9 
 10 
 
 104 
 11 
 11 
 
 10 
 
 94 
 
 92 
 
 10-2 
 
 13 
 
 114 
 134 
 12 
 
 50 
 
 iT 
 
 6 
 
 54 
 64 
 6 
 5 
 
 354 
 6- 
 
 14 
 
 li 
 
 14 
 14 
 14 
 14 
 14 
 
 12 
 
 1-5 
 
 8 
 8 
 7 
 6 
 5 
 
 44 
 
 G 
 
 5 
 
 62 
 
 6-2 
 
 
 10 
 
 
 
 
 10 
 
 6 
 
 7 
 
 5 
 44 
 
 6 
 6 
 
 6 
 
 74 
 
 
 
 8 
 
 9 
 
 10 
 
 11 
 
 .... 
 
 14 
 1 
 1 
 
 34 
 
 1-2 
 
 5 
 
 6 
 
 41 
 5 
 
 7 
 7 
 
 6 
 46 
 6-6 
 
 74 
 7 
 
 74 
 
 
 .... 
 
 
 94 
 4-7 
 
 24 
 6- 
 
 37 
 
 T 
 
 24 
 8- 
 
 31 
 
 103 
 
 Sculpture. — The umbonal region in this species is granulated. Out- 
 side of this region the granulation soon becomes varied by concentric 
 striae. In the anterior half of the valve, strong concentric furrows of 
 growth, still further diversify the surface. 
 
123 
 
 Horizon and locality. In the sandstones and sandy shales of the Lower 
 Etcheninian rocks at Young point near Geot ge River station of the Inter- 
 colonial Railway, N.S. This fossil and its associates are provisionally 
 assigned to Assise E. 2 a. 
 
 LlNGULELLA TUMIDA. PI. VI., figS. 6 a — C. 
 
 Lingulella tumida n. sp. Nat. Hist. Soc. Bull., vol. iv, p. 200, PI. 
 1, fgs. 2 a to e. 
 
 The following is a fuller description of the species above cited. 
 
 Shell substance corneous. A small, round, thick-shelled species. 
 
 The ventral valve is broadly ovate, with a projecting beak, the valve Lingulella. 
 is rounded down regulajaly on all sides to the margin. In the example 
 figured the beak is broken away, and a mould of the cardinal area ex- 
 posed ; here a triple ridge rises abruptly to a slightly projecting elongated 
 tubercle in the middle ; it is the mould of a pit in the ped.cle groove, 
 similar to that in Obolus and Obolella. 
 
 The visceral cavity shows three grooves impressed upon it, of which 
 Ihe middle one, like the pedicle groove of the cardinal area, is triple. 
 This valve is deepest in the posterior third. 
 
 Sculpture. — The surface of the shell is marked by rounded concentric 
 ridges, some of which show a beaded crest. 
 
 Size. — Length, 6 mm.; width 5 mm.; depth IJ mm. 
 
 Horizon and locality. — Assise E 3 e. Upper Etcheminian, Dugald 
 brook, Escasonie, N.S. 
 
 This species in its general form approaches Obolus, but the strong pro- 
 jecting umbo separates it. 
 
 Lingulepis Martinensis of the Protolenus fauna is like this in form and 
 surface markings, but is much larger. Lingulella Mia H. and W. of 
 the Middle Cambrian of the West is like this in outline, but the surface 
 markings are finer. 
 
 This species, L. tumida, is remarkable for the distinctness of the 
 channels on the callus, due to the sinews of the pedicle muscle! Even in 
 the pedicle groove these little grooves are seen. 
 
 Lingulella longovalis n. sp. PL VII., figs. 3 a—/. 
 
 A small elongately oval species approaching in form to Leptobolus. Lingulella- 
 
 longovalis^ 
 Ventral pointed, rather high along the median line in the posterior described.. 
 half ; flatter toward the front margin. Interior. — The hinge area is 
 
124 
 
 high, being about one-fifth of the length of the valve ; the cardinal 
 slopes and pseudodeltidium are of about equal width, and the latter is 
 obliquely striated. The pedicle groove suddenly contracts in width 
 toward the beak. The visceral callus is narrow and extends forward 
 about half of the length of the valve ; on each side of it runs a vascular 
 line, marking the advance of the anterior adductors. On each side of 
 the valve, half way between the callus aud the margin, run the vascular 
 lines that mark the advance of the lateral muscles ; these extend nearly 
 as far forward as the callus. The margips of the valves are flattened on 
 the inside. 
 
 The dorsal valve is more obtusely rounded behind than the ventral, 
 «nd in some examples is more tumid. Interior. — The height of the 
 hinge area is about one-tenth of the length of tj^^e valve. The callus is 
 quite long, extending four-fifths of the length of the valve ; along the 
 middle of the valve it is divided by a distinct median septum ; the front 
 of the anterior adductor scars is about one-third from the front of the 
 valve ; the lateral vascular ridges extend one-half of the length of the 
 valve, from the hinge. 
 
 Sculpture. — This consists of wavy, beaded ridges, that sometimes anas- 
 tomose ; there are about eight in the space of a millimetre. 
 
 Size. — Length of ventral valve 9 mm. ; width 6 mm ; depth about J 
 mm. The dorsal valve is nearly 1 mm. shorter. 
 
 Horizon aiid locality. — In the shales of E. 1 c and e, Dugald brook, 
 Escasonie, N.S. 
 
 As seen in Assise E. 1 e, this species is distinguished by its long oval 
 form and the projecting beak of the ventral valve. The callus of the 
 ventral valve is- a straight narrow band, and the striae of the hinge- 
 area run a long way forward on the edges of the valves. 
 
 Ooinpared This species in its oval form and elongated callus in both valves recalls 
 
 I^s eoUicia?''" Leptobolus, but the strong development of the hinge, the rather thick 
 shell, and the coarse wavy ornamentation of the surface of its valves, 
 range.^'"*^ seem to exclude it from that genus, as also the approximation of the vas- 
 cular trunks in the ventral valve. Still it may be regarded as the repre- 
 sentative in this fauna of Leptoholus collicia of the Upper Etcheminian. 
 
 It is not " satchel shaped ", that is squared at the front and angulate 
 behind, and so is not a typical Lingulella, but it is a common type of 
 Lingulelloid shell, for similar forms are to be met with throughout the 
 Cambrian system ; it is among the oldest Cambrian types, being found 
 in the Coldbrook volcanic terrane. 
 
125 
 
 The following table shows the size and proportion of parts in a number 
 of the valves of this species : — 
 
 VA.LVES of Lingulella longovalis from Assises E. 1 c and E. le. 
 
 FROM ASSISB E 1 C. 
 
 
 (The dimensions are in milli- 
 
 
 
 
 
 i 
 
 1 
 
 1 
 
 " 
 
 
 metres. ) 
 Number. 
 
 i 
 
 a 
 
 4 
 
 4^ 
 
 1 
 
 iffl 
 
 
 09 
 
 
 1 
 
 9 
 
 6 
 
 i 
 
 5 
 
 54 
 
 
 
 
 2 
 
 • 
 
 8 
 
 5 
 
 1 
 
 4 
 
 2 
 
 3 
 
 
 3. . 
 
 
 8 
 
 5 
 
 i 
 
 4 
 
 6 
 
 
 
 
 
 
 'S 
 
 4.... 
 
 
 8 
 
 5 
 
 S 
 
 4 
 
 6 
 
 2 
 
 3 
 
 ■u J 
 
 
 
 
 r 
 
 6 
 
 
 74 
 
 5 
 
 fi 
 
 3i 6 
 
 2 
 
 3 
 
 
 5. ... 
 
 
 8 
 
 6 
 
 i 
 
 4 
 
 
 
 
 
 7.... 
 
 
 8 
 
 6 
 
 i 
 
 5 
 
 
 2? 
 
 3 
 
 l^ 
 
 8. 
 
 
 8 
 
 5 
 
 1 
 
 4 
 
 
 2 
 
 
 
 
 
 
 
 64i 
 
 41 
 
 6 
 
 33i 
 
 234 
 
 10 
 
 12 Dimensions 
 &c. of this 
 
 
 
 
 
 
 
 
 
 
 1.. 
 
 Average 
 
 80 
 
 51 
 
 0-7 
 
 4 2 
 
 5-9 
 
 2 
 
 3 
 
 
 7i 
 
 6 
 
 1 
 
 5? 
 
 
 1 
 
 
 . 
 
 2 
 
 
 8 
 74 
 
 6 
 
 64 
 
 1 
 
 44 
 
 6 
 
 4 
 
 
 
 3.... 
 
 
 
 fi 
 
 4 
 
 
 64? 
 
 5 
 
 1 
 
 6 
 
 
 
 
 
 
 
 
 
 
 
 294 
 
 224 
 
 S 
 
 144 
 
 6 
 
 2i 
 
 
 
 7-4 
 
 S-5 
 
 1 
 
 4.8 
 
 6 
 
 •7 
 
 
 
 
 
 
 TKO 
 
 U ASSISE E I 
 
 c. 
 
 
 
 
 
 
 7 
 
 5 
 
 1 
 
 
 6 
 
 
 
 c£ 
 
 
 
 
 7 
 
 2 
 
 
 8 
 
 7 
 
 6? 
 4? 
 
 i 
 
 44 
 44 
 
 54 
 
 
 
 A 
 
 Q 
 
 3 
 
 > 
 
 Average 
 
 
 
 
 
 22 
 
 14 
 
 2i 
 
 9 
 
 114 
 
 
 3 
 
 
 7-3 
 
 4-6 
 
 0-7 
 
 4-5 
 
 5-6 
 
 
 3 
 
126 
 
 LINGULEPIS, Hall. 
 
 Characters of The late Professor James Hall described from the St. Croix Sandstones 
 Hall ' of the Mississippi valley a genus of Brachiopods, of which examples are 
 found in the Lower Etcheminian Fauna, It is described as ' shells li'n- 
 guloid, inequivalve, equilateral, oval-spa tulate or spatulate, muscular im- 
 pressions in one valve (dorsal) flabelliform, in the other tripartite, the 
 lateral divisions larger. Shell corneous, phosphatic. Lingula pinni 
 formis, Owen sp. is the type. 
 
 Hall's figure represents the callus as extending one half of the length 
 of the ventral valve, and a little more than half of the length of the dor- 
 sal. Walcott makes this species synonymous with«i^. acuminata, Conrad, 
 from the Potsdam sandstone ; in this the callus of the ventral valve ex- 
 tends two thirds toward the front and that of the dorsal also to this dis- 
 tance. The Etcheminian forms carry out the feature observed for others 
 of its genus, viz.: of a long callus to the dorsal valve ; this, in the species 
 named below, is proportionately longer than in the last named species and 
 much longer than in the other. Valves of this genus are common in 
 some portions of the Lower Etcheminian, but none have been found in 
 the Upper. We have found no flabelliform impression in the dorsal 
 valve, such as Professor Hall described for the type of the genus ; nor in 
 the ventral, lateral septa exceeding the callus in length. 
 
 LiNGULEPis Geegwa. PI. IX, figs. 3 a-f. 
 
 Lingulella Gregwa, n.sp. Bull. Nat. Hist. Soc. of N.B., vol. iv, p. 199, 
 pi. I, figs. 1 a to/ 
 
 Valves pentagonally oval except for she long projecting beak of the 
 ventral valve. 
 
 Lingulepia Ventral valve with a long somewhat acuminate apex, the rest of the 
 
 described. valve evenly rounded. Deltidial ridges scarcely distinct from the areal 
 border ; both are crossed by strise directed forward toward the pedicle 
 groove. The interior of this valve has the group of central soars well 
 forward, and shows impressions of vascular trunks, arching toward the 
 front margin. 
 
 The dorsal valve is pentangular ovate and more strongly arched longi- 
 tudinally than the ventral. The interior of this valve is remarkable for 
 the very advanced position of the central group of muscles, which are 
 about one-third from the front of the valve ; this gives the raised band 
 on which they are placed a ribbon-like appearance. The pits of the um- 
 bonal muscles and the posterior laterals are visible on the interior of this 
 
127 
 
 valve, and two arched lateral impressions at the side of the valve are 
 probably due to the vascular trunks. 
 
 Sculpture. — The valves in this species have a dull surface, which under 
 the lens is resolved into irregular beaded ridges, concentric to the umbo, 
 but often these ridges sink down, leaving a granular, or irregularly 
 • beaded surface. 
 
 Size. — Length of the ventral 14 mm. width 11 mm. The dorsal valve 
 is 2 to 3 mm. shorter than the ventral ; depth of the two valves together 
 about 3 mm. 
 
 Horizon and locality. In the gray shale of Assise E. 1 d. ; also a few 
 valves in E. 1 b. and E. 1. c. Lower Etcheminian, Dugald brook, Esca- 
 sonie, N. S. 
 
 This species has a long acuminate beak to the ventral valve like Lin- Compared 
 
 with otlr" 
 species. 
 
 ■gulepis pinni/ormis, but the dorsal valve is different from the dorsal of , 
 
 that species ; its central group of scars is advanced far to the front as in 
 Eoobolus, and in connection with this, a flattened band traverses the cen- 
 tre of this valve, the flattened area is narrower than that of Michtuitzia 
 monilifera and Oholus major and it is a smaller species than the latter. 
 
 This species is like L. acutangulus Roem* of the Upper Cambrian of 
 Texas, but is larger and differs in the more acuminate apex of the ven- 
 tral valve, and in having the central muscle scars parallel to the long dia- 
 meter of the valve. In the dorsal valve also the prints of the central 
 muscles are much farther forward on the valve, and those of the poste- 
 rior laterals farther apart. 
 
 Lingulepis Oregwa is a thin shell. In the species from Assise E. 1 c. 
 only a thin chitinous layer is preserved, some moulds have not even that. 
 No ventral valves were found in this assise. 
 
 In the Assise E. 1 d. at Boundary brook, the ventral, although ac- 
 cuminate, is blunted at the end, and the pedicle groove inside, rises 
 gradually from the visceral cavity, without the ledge or shoulder often 
 seen at the back of the shell in other species. 
 
 The above description covers the more salient characters of L. Gregwa, 
 but larger collections made in 1901, enable me to add some particulars. 
 
 In the majority of individuals the sides of the ventral valve are 
 straighter toward the beak, and the point is not so acuminate as repre- 
 sentedin the figures (la and b). Also the back part of the dorsal valve is 
 more prolonged than as represented in the figures {\d and «) ; so that there 
 is not usually such a discrepancy between the length of the valves as 3 mm. 
 
 * Proc. Nat. Mus, U. S., vol. xxi p. 392, pi. xxvii, fig. 6 and pi. xxvii, figs. 1 and 2. 
 
128 
 
 Surface orna- 
 mentation. 
 
 Dimensions 
 &o. of valves 
 from bugald 
 brook. 
 
 In Assise E 1 cf as well as in the others mentioned, the valves are thin 
 and they are flattened on the margins as seen in the shale. Being a thin 
 shell it was more liable to distortion than others occurring with it,, 
 excepting perhaps the thin-shel'.ed Leptoboli. 
 
 Sculpture (additional note). — The surface of the valves is seldom pre- 
 served except near the beak. A variation from the dull granulated sur- 
 face, where it is well preserved, consist of fine, somewhat irregular con- 
 centric shining ridges ; these anastomose irregularly, or at times pass into 
 an irregularly granulated surface. The dorsal valve shows the long callus 
 with the muscle scars sometimes more, sometimes less advanced toward 
 the front. The strise of the cardinal area pass into the depression of the- 
 visceral cavity, so that they have no office of articulation, but appear to 
 mark the line of attachment of a ligament or parietal band connecting 
 the back of the two valves ; such ligament or bond must have been 
 divided on the ventral side for the passage of the pedicle. The connec- 
 tion of the two valves seems to have been very like that in Obolus. 
 
 The species exhibits considerable variation in form, as may be gathered 
 from the following table. 
 
 Valves of Lingulepis Gregwa in Assise E. 1 d., at Dugald brook. 
 
 Ventbals. 
 
 DOBSALB. 
 
 
 
 
 d 
 
 
 
 
 
 
 a 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 (0 
 
 1 
 
 i 
 
 4 
 
 u 
 
 Area. 
 
 
 1 
 1 
 
 M 
 
 1 
 
 1 
 
 Area. 
 
 1 
 
 
 
 
 mm. 
 
 mm. 
 
 
 
 
 
 mm. 
 
 mm. 
 
 
 
 
 1 
 
 12 
 
 IW 
 
 105 
 
 138 
 
 
 1 
 
 11 
 
 104 
 
 
 05 
 
 115-5 
 
 100 
 
 2 
 
 13 
 
 10 
 
 1-30 
 
 130 
 
 1 s 
 
 2 
 
 10 
 
 10 
 
 
 00 
 
 100 
 
 - 
 
 3 
 
 14 
 
 9 
 
 1-55 
 
 126 
 
 C 1 
 
 3 
 
 lOi 
 
 94 
 
 
 11 
 
 99-9 
 
 9. 
 
 4 
 
 12 
 
 9 
 
 1-33 
 
 108 
 
 s 
 
 4 
 
 io| 
 
 94 
 
 
 10 
 
 99-8 
 
 
 6 
 
 11 
 
 8 
 
 1-38 
 
 88 
 
 s 
 
 6 
 
 10 
 
 94 
 
 
 05 
 
 95 
 
 i 
 
 6 
 
 11 
 
 8 
 
 1-38 
 
 88 
 
 § 
 
 6 
 
 10 
 
 94 
 
 
 05 
 
 95 
 
 
 7 
 
 11 
 
 8 
 
 1-38 
 
 88 
 
 IS 
 
 7 
 
 84 
 
 8 
 
 
 06 
 
 68 
 
 
 8 
 
 10 
 
 8 
 
 1-25 
 
 80 
 
 X 
 
 8 
 
 84 
 
 8 
 
 
 06 
 
 68 
 
 n 
 
 9 
 
 10 
 
 8 
 
 1-25 
 
 80 
 
 « 
 
 9 
 
 8 
 
 7* 
 
 
 07 
 
 60 
 
 ^ 
 
 10 
 
 10 
 
 7 
 
 1-21 
 
 70 
 
 ^ 
 
 10 
 
 7 
 
 7 
 
 100 
 
 49 
 
 lO 
 
 11 
 
 9 
 
 7 
 
 1-29 
 
 63 
 
 o 
 
 
 
 
 
 
 
 12 
 
 9 
 
 7 
 
 1-29 
 
 63 
 
 i-*? 
 
 
 
 
 
 
 
 13 
 
 9 
 
 7 
 
 1-29 
 
 63 
 
 J" 
 
 
 
 
 
 
 
 14 
 
 84 
 
 7 
 
 1-21 
 
 59-5 
 1244-5 
 
 
 
 
 
 
 
 
 1494 
 
 1144 
 
 18 16 
 
 
 
 94 
 
 89 
 
 10-65 
 
 860 
 
 
 
 
 
 
 Average. 
 
 10-7 
 
 8-2 
 
 1-30 
 
 
 
 
 4.9 
 
 8-9 
 
 1-nR 
 
 
 
 
 1 
 
 
 
 
 
 This table may be compared with the following of valves from another- 
 locality. 
 
129 
 
 Valves of Lingulepia Gregwa from Assise E. 1 d., at Boundary brook. 
 
 Ventrals 
 
 Dorsals. 
 
 
 
 
 a 
 
 
 
 
 
 
 ^ 
 
 
 
 Number. 
 
 i 
 
 4 
 
 •a 
 
 1 
 
 Area. 
 
 
 Number. 
 
 "Si 
 
 a 
 
 ■i 
 
 ■a 
 
 1 
 
 Area. 
 
 t 
 
 
 s 
 
 ^ 
 
 PM 
 
 
 O 
 
 
 ^ 
 
 ^ 
 
 fl 
 
 
 O 
 
 
 mm. 
 
 mm. 
 
 
 
 
 
 mm. 
 
 mm. 
 
 
 
 
 1 
 
 12 
 
 9 
 
 1-33 
 
 108 
 
 100 
 
 1 
 
 11 
 
 94 
 
 116 
 
 105 
 
 100 
 
 2 
 
 10 
 
 9 
 
 111 
 
 90 
 
 
 2 
 
 104 
 
 9 
 
 116 
 
 94 
 
 
 3 
 
 Hi 
 
 7 
 
 1-64 
 
 81 
 
 o 
 
 3 
 
 9i 
 
 94 
 
 100 
 
 90 
 
 s 
 
 4 
 
 10 
 
 8 
 
 1-25 
 
 80 
 
 4 
 
 10 
 
 9 
 
 111 
 
 90 
 
 J^ 
 
 5 
 
 10* 
 
 7* 
 
 1-40 
 
 79 
 
 5 
 
 10 
 
 8 
 
 1-25 
 
 80 
 
 6 
 
 10 
 
 ^ 
 
 1-33 
 
 75 
 
 
 6 
 
 9 
 
 84 
 
 106 
 
 76 
 
 
 7 
 
 9i 
 
 7* 
 
 1-26 
 
 71 
 
 
 7 
 
 9 
 
 8 
 
 112 
 
 72 
 
 
 8 
 
 10 
 
 7 
 
 1-43 
 
 70 
 
 o 
 
 8 
 
 SA 
 
 8 
 
 106 
 
 68 
 
 O 
 
 9 
 
 9J, 
 
 7 
 
 1-36 
 
 66 
 
 T 
 
 9 
 
 8 
 
 74 
 
 107 
 
 60 
 
 t 
 
 10 
 
 9 
 
 7 
 
 1-29 
 
 63 
 
 r 1 
 
 10 
 
 8 
 
 7 
 
 114 
 
 56 
 
 o 
 
 11 
 
 9 
 
 6 
 
 loO 
 
 54 
 
 S 
 
 11 
 
 n 
 
 74 
 
 1-00 
 
 56 
 
 o 
 
 12 
 
 9 
 
 fi 
 
 1-50 
 
 54 
 
 
 12 
 
 n 
 
 74 
 
 100 
 
 56 
 
 
 13 
 
 7i 
 
 6 
 
 1-25 
 
 45 
 
 
 13 
 
 7A 
 
 7 
 
 1-07 
 
 54 
 
 J 
 
 14 
 
 7 
 
 6 
 
 117 
 
 42 
 
 
 14 
 
 7 
 
 7 
 
 100 
 
 49 
 
 1 o 
 
 15 
 
 7A 
 
 5A 
 
 1-36 
 
 41 
 
 15 
 
 8 
 
 6 
 
 1-33 
 
 48 
 
 CO 
 
 16 
 
 fi* 
 
 n 
 
 1-30 
 
 32 
 
 16 
 
 7 
 
 64 
 
 108 
 
 45 
 
 
 
 
 
 
 J 
 
 17 
 
 6i 
 
 54 
 
 102 
 
 36 
 
 
 1484 
 
 111 
 
 21-48 
 
 1051 
 
 
 
 
 
 
 1444 
 
 131 
 
 18-63 
 
 1135 
 
 
 Average. 
 
 9-25 
 
 6-94 
 
 134 
 
 
 
 Average 
 
 8-5 
 
 7-7 
 
 1-09 
 
 
 
 Dimensions 
 &o. of valves 
 from Bound- 
 ary brook. 
 
 The variation in the form of the valves in these two tables is, in many 
 cases, due to the distortion of the valves after entombment. 
 
 If the remarks on orientation in an earlier part of this report be referred 
 to, it -will be seen that more than two thirds of the valves of thi.s species 
 both at Boundary brook and Dugald brook have been affected by orienta- 
 tion, and as this orientation is lengthwise of the valley of Indian brook 
 of which these brooks are tributaries, that proportion of the ventrals are 
 elongated beyond their natural form. In this table the ventrals average 
 a third greater than their length ; but they have been subject to the 
 influence above referred to, and it may be assumed that in the original 
 relation of form the length did not exceed the width by more than a 
 quarter. 
 
 To this cause are traceable most of the extreme elongation of valves ; Remarks on 
 but that there was a considerable variation naturally, is seen because tables. ^^ 
 valves oriented in the same direction show variation in comparative width 
 and length. The length and width of the dorsal valve are so nearly 
 equal that the effect of distortion and variation of form from biological 
 
 9 — c. E. 
 
130 
 
 causes is not so obvious, nevertheless the variability of the species is 
 evident on examination of the accompanying tables. Ten valves from 
 Dugald brook show an average of 5 p.c. excess of length, and seventeen 
 valves, from Boundary brook an average of 9 p.c. The attitude of the 
 valves has not affected their form in the same way as it has the ventral 
 valves, as was explained in the remarks on orientation, and it may be 
 assumed that the natural width and length of the dorsal valves of this 
 species were about equal to each other. 
 
 Another fact noticeable in this connection is that only a few valves 
 reach the full adult size. Also the shells from Dugald brook grew to a 
 larger size than those from Boundary brook, where the measures of Assise 
 E. 1 d. are more sandy. This is an unexpected result, as in later Camb- 
 rian terranes Lingulepis has been found especially to characterize sand- 
 stones. But it agrees with the habit of this particular species which, 
 while rare and small in the earlier and more sandy assises of Division 1, 
 became plentiful when the mud beds of Assise E. 1 d. were laid down 
 (see annotation of species in the several assises p. 78). 
 
 luting stages Cicatrices or resting stages in Lingulepis Oregwa. — This species was 
 apt to develope concentric grooves or cicatrices at certain stages of growth. 
 Thus of eight ventrals from Dugald brook three show strong cicatrices 
 at 7 mm. from the umbo and all show them at 9 mm., but not so distinctly. 
 Of thirteen ventrals from Boundary brook twelve show grooves at 6 mm. 
 from the umbo and eight show them, but not so well marked, at 8-9 mm. 
 Of ten dorsals from Dugald brook, eight show a groove usually strong, 
 alt about six mm. from the umbo, and four show one at 8-9 mm. Of 
 fifteen dorsal valves from Boundary brook, eleven show a groove, often 
 strong, at about 6 mm. from the umbo, and three show weak ones at 8-9 
 mm. from that point. At both localities a few ventrals show resting 
 grooves at 4 mm. from the umbo. 
 
 Allowing one to two millimetres for the extra length of the ventral valve 
 these cicatrices on the two valves would come opposite each other. The 
 deep ones are apt to be placed just outside of the visceral cavity of the 
 dorsal valve, therefore considerably beyond the point of attachment of 
 the central group of muscles of the ventral valve. The corrugation caused 
 by these cicatrices would, no doubt, serve to strengthen these thin shells ; 
 yet we find some that have been decollated at this line, as the band of the 
 visceral callus in a few valves has been found to extend quite to the front 
 of the valve. 
 
 Mr. Walcott has made some curious mistakes in regard to this species.* 
 
 First he places it as a species of the Paradoxides beds, when it actually 
 
 *Oambrian Eraohiopoda, &o., Bull. U.S., National Muaeiim, vol. xxiii, pages 692-694. 
 
131 
 
 occurs 1,000 feet below. Second he assumes that Leptobolus atavus, a 
 shell quite dififerent in form is the young of this species. Third that 
 Lingulella titmida, a thick shelled species is also the young of Lingulepis 
 Gregwa, which is thin-shelled. How the two named can be the young of this 
 species seems difficult to understand, seeing that they occur in layers 300 
 feet above it, and that L. Gregwa does not occur in the layers with them, 
 nor they in the lower horizon with it. These errors seem the more 
 remarkable, since Mr. Walcott sent to me for these specimens for study, 
 and they were distinctly marked as belonging to the Etcheminian terrane. 
 
 Var. 
 
 EOBDSTA, n. var. 
 
 Intermingled with the above species there are valves of a form nearly as Variety 
 large, which differs in its thicker and stiffer test, its more shining surface 
 and straight posterior margins of the ventral valve (not incurved as in 
 L. Gregwa). The concentric growth grooves are rare or weak in this 
 form. It is placed here as a variety until better known. 
 
 The following table will show its relation to L. Gregwa : 
 Valves of var. robusta from Assise E. 1 d. 
 
 «• r 
 > 
 
 I J 
 
 Number. 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 Average 
 
 1 
 
 2 
 
 3 
 
 4 
 
 Average 
 
 9|— C B. 
 
 ft 
 
 g 
 
 lOi 
 10 
 
 Si 
 
 9 
 
 10 
 
 48 
 
 9-6 
 
 10 
 7 
 6 
 
 10 
 
 33 
 
 8-2 
 
 34 
 
 6-8 
 
 25i 
 
 6-4 
 
 6i 
 
 13 
 
 3i 
 
 •94 
 
 18 
 
 4-5 
 
 18 
 
 4-5 
 
 Resting 
 
 7 
 7 
 
 74 
 
 8i9 
 8 9 
 
 214 164,9 
 
 7-2 82,9 
 
 22 8 
 
 5'5 8 
 
 54 
 
 mm. 
 4 
 
 34 
 
 71 Dimensions 
 &o. of this 
 
 3 ■ 7 variety. 
 
132 
 
 LiNGU^EPis RoBERTi PL VIII., Figs. b a and h. 
 
 The following species was described with Lingulella Selzvyni in Trans. 
 Roy. Soc. Can., 2nd Ser., vol. I, sec. iv, p. 256 : 
 
 " LiNQDLBLLA RoBERTi, n, sp., P). I., Fjgs. 2 a and h. 
 
 Lingulepis " Broadly ovate, the ventral value acuminate, having a low median ridge 
 
 described. ^^ ^^^ posterior third, and slightly upturned at the beak. The dorsal 
 valve tumid posteriorly, with a narrow hinge-margin, the valve has a 
 mesian groove in the posterior quarter, and is flattened toward the front. 
 In the ventral valve the inner surface of the thickened posterior part 
 of the valve carries two pairs of diverging ridges, the inner pair termi- 
 nating at the scars of the anterior adductors, of the outer pair about equal 
 length, but continuous with impressions of the curving vascular trunks. 
 
 The dorsal valve also has in its interior four diverging lidges ; within 
 the two outer ones at the back of the shell is the impression of the pos- 
 terior adductor muscle ; and within the two inner ones, one-third from 
 their ends, are the oval pits of the anterior adductors ; between these 
 scars, and extending backward in the valve, is a faintly marked mesian 
 ridge, placed about one-third from the posterior end of the valve. The 
 pits of the anterior adductors diverge somewhat at their anterior ends, 
 and a short distance in front of them are two small, round pits, near 
 together, which mark the points of attachment of the anterior adjustors. 
 
 Sculpture. — This consists of irregular concentric striae which inoscu- 
 late with one another, producing a surface of broken ridgelets, similar to 
 that of an Acrothele; the concentric ridges are of unequal size, and there 
 are occasional more distinctly marked growth-lines. 
 
 Size. — Length of the dorsal valve, 13 mm.; width about the same ; 
 the ventral valve is about 1 -5 mm. longer. 
 
 Locality. — Same as Lingulella Selwyni. Found in a sandy limestone 
 of Assise E. 2 (a ? ) by Messrs. Weston and Robert. 
 
 This species is very little larger than Lingulella Sel-wyni, but is dis- 
 tinguished by its radular ornamentation and thicker valves ; also by its 
 acuminate upturned beak, its tumid dorsal valve, and by the position of 
 the central muscular scars of this valve ; these scars are in the posterior 
 half of the valve, but in L. Selwyni about the middle of the valve." 
 
 This species approa,ches Lingulepis in the form of the beak of the 
 ventral valve, and in the advanced position of the lateral muscles, as in- 
 dicated by the lateral septa. 
 
133 
 
 From Lingulepia Oregwa it is easily distinguished by the short callus 
 of the dorsal valve, and by the sculpture. 
 
 LiNGULEPIS LONGINERVIS, n. sp. PI. VII figs. 6, a — g. 
 
 A thickshelled species, with the dorsal somewhat, and the ventral valve Lingulepis 
 greatly prolonged. deSed!'' 
 
 The ventral valve has an even arch to the anterior and posterior end 
 on the axial line ; it is more strongly arched down at the sides in the post- 
 erior half than elsewhere. The sides are straight from the umbo, beyond 
 the middle of the shell, and thence regularly rounded. Interior. This 
 shows a high hinge area, with very oblique strise on the areal borders, 
 and prolonged margin of the cardinal area, extending forward along the 
 «dge of the valve; the pedicle groove is deep and broad ; the areal slopes 
 have a great width near the umbo, and increase slowly in going forward. 
 Extending from the hinge forward along the middle of the valve is a long 
 visceral callus, on each side of which at the mid length of the valve are oval 
 scars (of the central muscles ?) ; in front of these and more approximated is 
 a small pair of scars ( " k " laterals ? ) The print of the laterals in these 
 valves is heavy and extends nearly as far forward at the central scars ; 
 they are not as far from the central scars as these are from each other. 
 
 The dorsal valve is oval and has a low flat umbo ; in most adult 
 valves the posterior slope is strongly arched down, and the lateral .slopes 
 less so. The valve for most of its length is flattened along the median 
 line. Interior. The hinge area is high and as in the ventral, the striae 
 of the slopes are quite oblique. There is a well marked long visceral cal- 
 lus extend to within an eighth of the front of the valve. The paired 
 scars of the centrals are nearly two thirds of the length of the valve from 
 the umbo, and those of the " j '' laterals of adult valves less then one 
 quarter of the length of the valve from its front. The laterals " 1 " and 
 ''k," are well shown in this valve, "1" being opposite the central muscles 
 and " k " more advanced, smaller, and oblique ; the above laterals are 
 about as far from the centrals as these are apart. Traces of vascular 
 trunks are seen inside of the laterals. 
 
 Stiulpture. — Beside the concentric growth grooves, which are prominent 
 on these valves, the lateral slopes display fine concentric ridges, about 
 ten in the space of a millimetre ; these little ridges are somewhat irregular 
 in their course, and sometimes anastomose ; elswhere they sink down 
 so as to become rows of granulations ; ou the dorsal slope they merge into 
 an irregularly rugose surfacei, aoross which run broken, radiating ridges, 
 directed toward the front margin. 
 
Dimensions 
 &c. of the 
 
 valves. 
 
 134 
 
 Size. — Ventral valve, length 11 mm. j width 8 mm. ; depth, 1-J mm. 
 The dorsal valve is 2 mm., shorter than the ventral. 
 
 Horizon and locality. — Dark purplish gray sandstones of E. 26, at 
 Dugald Brook, Escasonie, N.S. Not rare. 
 
 The following table gives measurements of valves from this horizon : — 
 Valves of Lingulepis longinervis from Assise E. 2 h. 
 
 — 
 
 1 
 
 Length. 
 
 Width. 
 
 Depth. 
 
 Length 
 callus. 
 
 Resting stages 
 
 of 
 
 growth. 
 
 Hinge 
 area. 
 
 1? 
 
 1 
 2 
 3 
 
 4 
 5 
 
 ± 
 
 2 
 3 
 
 4 
 5 
 
 mm. 
 
 1?* 
 9 
 
 10 
 94 
 
 mm. 
 
 7 
 8 
 
 f 
 7 
 
 mm. 
 
 1 
 'l' 
 
 mm. 
 
 5" 
 
 6? 
 
 mm. mm. mm. 
 
 6 8 
 
 8 94 
 64 8 
 6 84 
 
 mm. 
 24 
 
 IJ 
 
 
 a 
 
 
 > 
 
 
 
 
 
 
 
 49 
 
 354 
 
 i\ 
 
 11 
 
 184 324 94 
 
 24 
 
 
 10. 
 
 7- 
 
 11 
 
 5-5 
 
 6 8- 9-6 
 
 2 5 
 
 f 
 
 9 
 
 8 
 
 10? 
 
 1 
 
 1 
 1 
 
 1 
 
 1 
 1 
 
 8 
 
 1 
 
 6 
 
 
 
 lA 
 
 9 
 
 6 
 64 
 
 14 
 
 ^l 
 
 
 
 41i 
 
 374 
 
 5 
 
 35 
 
 124 9 
 
 14 
 
 
 8 
 
 7-5 
 
 1 
 
 7 
 
 62 9 
 
 1-5 
 
 This species is remarkable for the long large callus of the dorsal valve, 
 and for the prolonged beak of the ventral valve. The average distance 
 of the visceral callus of the dorsal from the front of that valve is only one- 
 eighth of the valve's length. As the laterals of this valve also come far 
 forward it may be assumed that the visceral cavity is unusually large. 
 
 Oholua ccelatus Volb. sp.* presents somewhat similar appearances in 
 the dorsal valve, but its centrals are not nearly so far advanced. L. (0.) 
 acutangula, Roem.f has poinds of resemblance in the ventral valve, especi- 
 ally in the prolonged beak, and oblique striae on the hinge area. 
 
 * Uber die Brachiopoden Obolus & Lingulella, Mem. Acad. Imp. d. Sci. St. Petersb., 
 viii, ser. vol. iv, No. 2, pi. ii, figs. 21c. and 22o. 
 
 t Cambrian Braohiopoda, Obolus & Lingulella, U.S. Nat. Mua. Proc. vol. xxi, pU 
 xxvii, fig, 6. 
 
There is a scarcity of growth cicatrices on the valves of this species ; 
 seldom are more than two seen oa the ventral, and on the dorsal, one or 
 none. This may be due to the advanced position of the muscle scars and 
 the thickness of the shell. 
 
 0B0LU8, Eichwald. 
 
 " In default of more exact criteria, we have adopted here and elsewhere Genus Obolus 
 the following characters for distinguishing Obolus from Lingulella, viz : tarized. 
 roundness of outline, short cardinal area and depressed beakv, advanced 
 position of muscle scars in the valves, and strong arch of the vascular 
 trunks in the ventral as well as the dorsal valve. (Subgenus Palseobolus 
 is an exception.) There is, however, a more important distinction, which, 
 in consequence of imperfect preservation of the valves, can seldom be 
 observed, that is, the position of the secondary muscles of the central 
 group in the ventral valve, as compared with the great muscle of that group. 
 In Obolus they are lateral, but in Lingulella anterior to the great muscle. 
 This shows a radical difference of structure between the two genera." 
 [Bull. Nat. Hist. Soc. N.B„ vol. iv, page 198.] 
 
 There is also an important distinction in the advanced position of the 
 scars of the " j " laterals in the dorsal valve of Obolus ; in this genus 
 they are placed toward the front of the valve, but in Lingulella they are 
 not far removed from the centrals. As described by tte Russian writers 
 Obolus (sens, strict.) appears to range from the Dictyonema zone upward; 
 it is, therefore, properly an Ordovician genus, while Lingulella is numerous 
 in the Cambrian. For practical purposes (owing to difficulty in finding 
 valvess howing the internal markings distinctly), it is convenient to use the 
 diagnosis of Obolus given above, while at the same time it must be 
 acknowledged that it is an unsatisfactory one. And the more so because 
 wherever we have been able to Und the internal markings of the Etche- 
 minian Oboli they do not agree with the typical interior of Oboli 
 obtained on the shores of the gulf of Finland. In this way we have 
 come to recognize the fact that these Canadian Oboli, though similar in 
 the form of the valves to the later ones of Russia, have had diflferent 
 origin. Of the two types that occur in the Etcheminian terrane, the 
 older one in the arrangement of the central group of scars of the dorsal 
 differs more from Obolus than that from Lingulella, and we have thought 
 it necessary to establish a subgeneric distinction, as follow : — 
 
 EOOBOLUS, n. subgenus. 
 
 In Obolus proper the anterior adductors of the dorsal valve are far Eoobolus new 
 apart and have a position at the mid length of the valve, while the " j " sub-genus. 
 
136 
 
 laterals are far advanced to the f roat and are placed close together ; in 
 Lingulella the anterior adductors are also abont the mid length of the 
 valve, while the " j " laterals, approximated as in Obolus, are a little in 
 front of these adductors; in Eoobolus a third relation between thesemuscle 
 pits is found ; the group of muscles as a whole was in front of the centre of 
 the valve, but the two pairs of muscles were almost or quite in line, longi- 
 tudinally, with each other, and are arranged more or less in a quadrate 
 manner. Beside these four pits of the central group, usual in the Lingu- 
 loid Brachiopods, there is in this genus a fifth, being a small single scar 
 on the axial line, sometimes equidistant from the other four and sometimes 
 a little in front of the " j " laterals. This pit appears to mark a small 
 muscle whose office is unknown. 
 
 The arrangment of the vascular trunks in this subgenus, so far as 
 known, is similar to that in Obolus and Lingulella. This subgenus, 
 Eoobolus, characterizes the Lower Etcheminian Fauna. 
 
 Obolus triparilis n. sp. PJ. VIII, fig. 4 a — c and PI. IX, figs. 1 a and h. 
 
 A lenticular, rather thick shelled species, the inside of the shell showing 
 
 Obolus (B.) concentric rows of perforations like Lingulella Davisii. 
 tnparilis 
 
 deaonbed. Ventral valve longer than wide, decidedly pointed behind, the part of 
 
 the valve in front of the umbo, rather prominently raised and the 
 slopes on each side depressed ; valve somewhat flattened in front, else- 
 where evenly arched. Interior not known, but there are indications 
 that the callus extended as far as the middle of the valve. 
 
 Dorsal valve about as long as wide, somewhat flattened along the 
 median line. Interior. A broad striated hinge-area lies across the car- 
 dinal end of the valve and runs forward on the lateral margins. Along 
 the middle of the valve runs a long, raised callus, extending in some 
 examples to within a quarter of the front of the valve, in others, less ; 
 this callus is about one fifth of the width of the valve ; it is traversed 
 lengthwise by a median and two lateral septa, of which the latter branch 
 near the front, each branch, and the median septum extending respectively 
 to three small muscle scars. Of the central group of muscle scars the two 
 posterior are larger than the others which are of nearly equal size, and some- 
 times nearly equally advanced toward the front of the valve. A pair of 
 vascular ridges extend out on each side of the valve nearly opposite to the 
 central muscle scars ; at the end of this ridge there appears to be a 
 minute muscle soar. Anothef pair of shorter ridges outside of these, 
 mark the position of the main lateral muscles. 
 
137 
 
 Sculpture. — This consists of lamellose concentric ridges ; toward the 
 front margin of the valve there are about 8 in the space of a millimetre ; 
 the ridges are more closely set toward the sides and at the mid length of 
 the valve ; they anastomose moi e or less, and sometimes two or three run 
 into another ridge, and are abruptly cut off. 
 
 Size. — Length of ventral 9 mm. ; width 8 mm. ; depth about 1^ mm. 
 The dorsal is of the same depth, and is 1 mm. shorter. 
 
 Horizon and locality. — Sandstone and grit layers of Assise -E 1 b, and 
 in the shales of E 1 c at Dugald brook, Escasonie, N.S. 
 
 This species differs from 0. cequiputeis in the weakness of the anterior Cratrasted 
 scars of the central group, in the sharper sculpture and the strong pro- ^*'' ""^^"^ 
 longed lateral septa somewhat curved at the anterior end. From 0. 
 discus in the advanced position of the middle one of the three minor scars 
 of central group and in the marked lateral septa, as well as the project- 
 ing umbo of the ventral valve. 
 
 This species departs from typical Obolus in the projecting umbo, strong 
 lateral septa and advanced position of the whole centra] group of muscle 
 scars in the dorsal valves. 
 
 The following are dimensions of thu valves in this species : 
 
 species. 
 
 Valves of Obolus triparilis from Assise E. 1 h, 
 
 — 
 
 Number. 
 
 4. 
 
 J 
 
 
 1 
 
 .a 
 1 
 
 Resting 
 stages 
 
 of 
 growth. 
 
 a 
 W 
 
 1 
 
 1 
 
 M 
 
 1 
 
 mm. 
 
 84 
 
 mm. 
 
 7 
 
 7 
 
 mm. 
 1 
 
 1 
 
 mm. 
 
 mm. 
 44 .... 
 7 
 
 mm. 
 
 mm. 
 
 1 
 
 2 
 
 li 
 
 
 ^l 
 
 1... 
 2... 
 
 
 
 
 
 17 
 
 14 
 
 2 
 
 
 4i 7 
 
 1* 
 
 &;c. of this 
 
 
 8-5 
 
 70 
 
 10 
 
 
 4-5 70 
 
 1-5 
 
 
 
 
 
 f 
 
 8 
 9 
 
 7 
 
 8 
 10 
 
 8 
 
 1 
 1 
 1 
 
 6* 
 5 
 
 7 
 
 ^. 7 
 64 
 
 1 
 1 
 1 
 3 
 
 5 
 
 11 
 
 
 5 
 
 6 
 
 
 
 
 
 
 24 
 
 26 
 
 3 
 
 16i 
 
 5i m 
 
 16 
 
 
 8 
 
 80 
 
 10 
 
 5-5 
 
 5-5 6-8 
 
 10 
 
 5 3 
 
 
 
 
138 
 
 Obolus discus, n.sp. PI. VIII, figs 3 a-d 
 
 qbolus{E.) Evenly lenticular with the beak of the ventral slightly projecting. 
 
 described. Length and breadth about equal. 
 
 - Ventral valve rather flat, with an appressed umbo, scarcely elevated 
 above the cardinal line, and but slightly projecting beyond the general 
 circular contour of the valves. Interior not known. 
 
 The dorsal valve is evenly sloped toward the margins, which are some- 
 what flattened. A median sulcus appears in the back of the valve, near 
 the hinge, and becomes wide and shallow towards the front ; it extends 
 two-thirds of the length of the valve. Interior. — The cardinal area is 
 about one-seventh of the length of the valve, and has a wide pseudo-del- 
 tidium, transversely striated ; this area is twice as wide at the margin of 
 the visceral cavity as it is at the apex of the shell ; the cardinal borders 
 also are wide and are traversed by strise that turn outward toward the 
 lateral margin of the valve. Lengthwise along the centre of the valve is 
 a raised callus that carries the central muscles ; it is marked by a median 
 and two lateral furrows, that extend about half of the length of the valve ; 
 at the front of the callus are the central group of scars (arranged in quin- 
 cunx?) of which the two posterior are much larger than the others. The 
 two anterior scars are connected with the two posterior by a faint thread- 
 like ridge. The small central scar is about midway between the four. 
 
 Sculpture. — This consists of irregular, anastomosing, beaded ridges. 
 Over some parts of the valves these markings are hardly distinguishable, 
 and the surface appears granulated. 
 
 Size.— The) largest ventral observed was 10 mm. long, and the largest 
 dorsal 9 mm.; the width is about 9 mm., and the depth 1^ mm. 
 
 Horizon and locality. — Sandy layers in the shale of Assise E, 1« at 
 Dugald brook, Escasonie, N.S. Not rare. 
 
 This difiers from the next in its somewhat smaller size and more exactly 
 lenticular form of the dorsal valve ; in the less prominent umbo of the 
 ventral, as well as the more irregular sculpture and the flattening of the 
 dorsal. The umbo of the dorsal seems to have been shortened. 
 
 The material for this species is scanty, and the following are dimen- 
 sions &c. of the valves examined : — 
 
139 
 Valves of Obolus discus from Assise E. 1 e. 
 
 — 
 
 Number. 
 
 ^ 
 
 4 
 
 i 
 
 ■i 
 ""J 
 
 1 
 
 Resting 
 stages 
 
 growth. 
 
 
 
 M 
 
 4i 
 
 r 
 
 Ventral 
 
 1 
 
 mm. 
 10 
 
 mm. 
 10 
 
 mm. 
 
 1 
 
 mm. 
 54? 
 
 mm. 
 64 8 
 
 nun. 
 
 14 
 
 mm. 
 
 
 
 
 Dorsals 
 
 1 
 
 2 
 
 9 
 
 9? 
 
 74 
 
 9 
 9? 
 
 .7 
 
 1 
 
 1 
 
 4 
 
 6 
 
 44 
 
 44 64 
 
 6? 
 3 54 
 
 4? 
 
 1 
 
 4? 
 
 6? 
 
 3... 
 
 
 
 Average 
 
 
 
 254 
 
 25 
 
 24 
 
 104 
 
 74 18 
 
 2? 
 
 6? 
 
 
 8 5 
 
 8-3 
 
 0-8 
 
 5-2 
 
 3-7 6 2 
 
 ■7? 
 
 ■6? 
 
 Dimensions 
 &c. of the 
 
 valves. 
 
 Obolus .equiputeis, n. sp. PI. VIII, "figs, a — e. 
 Valves corneous equaliy lenticular, nearly orbicular in outline: um- Otiolus (E. ) 
 
 ^ ■' ' ■' sequiputeis 
 
 bones depressed. described. 
 
 Ventral valve with a short, low beak, having a narrow conical pedicle 
 groove. Cardinal area broad. Interior. Opposite the pedicle groove is a 
 small shallow pit, perhaps marking the point of attachment of the ped- 
 icle muscle. The lozenge heart-shaped area, or callus in front, is bordered 
 by a strong furrow, outside of which, on each side in front, is the 
 triangular imprint of the central group of muscles, In front of the 
 middle of the valve, near the axial line are two minute pits, extending 
 back from these across the heart-shaped area is a faint slender median 
 ridge. Two strongly marked ridges, diverging' from the umbonal region, 
 separate the lateral group of muscles- from the depression of the visceral 
 cavity ; these muscle scars extend forward on each side of the valve from 
 the cardinal region as far as the centre of the heart-shaped area. In 
 front of the ridges above named, are the grooves of the vascular trunks, 
 which sweep around towards the front of the valve parallel to its margin. 
 
 The dorsal valve has a nearly orbicular outline, and a rather prominent, 
 broad umbonal region. Interior. This shows a broad and long cardinal 
 area. At the back of the valve, close to the hinge on each side of the 
 umbonal region, are small scars apparently due to the posterior adductor- 
 From the hinge on each side of the median line, a sharp ridge runs forward 
 
140 
 
 as far as the scars of the central mlisoles, which are in the posterior third of 
 the valve, are oval in form, and are about as far apart as half of the width 
 of the cardinal line. A short distance in advance of these scars, but in 
 the anterior half of the valve are the prints of the two anterior lat- 
 erals; these are round, unusually large and are as far apart as the 
 central muscles. At about equal distance from these four muscle scars 
 and at the centre of the valve is a small pit, with a still smaller one in 
 front of it, whose function is unknown. A short mesian ridge extends 
 forward from between the scars of the anterior "j " laterals to two diverg- 
 ing furrows in front of these ; those run from the point of divergence half 
 way to the margins of the valve. In front of the forks of these furrows 
 is a shallow round area, which with the space between the forked groove, 
 is raised on the inside of the valve. . Two strong ridges more widely sepa- 
 rated at the back than those of the ventral valve, and less divergent, 
 spread from the umbo. Outside of these diverging ridges are the prints 
 o^ the posterior laterals. Running forward from the ridges in a curve 
 parallel to the margin of the valve, vascular grooves are faintly indicated, 
 and still more indistinct are traces of the interior branches of these 
 trunks. 
 
 Sculpture. — At the umbo the dorsal valve is granulated, but concentric 
 striae appear at one millimetre from the umbo, and farther out the surface 
 of the valve is diversified with numerous concentric ridges, to which the 
 roughened surface of the shell give a granulated crest. The ventral valve 
 is similarly marked, but there are concentric growth furrows at intervals. 
 
 Size. — The ventral valve has a length of 12 mm. and a width of 11 mm. 
 In the dorsal the length and width are each 11 mm. 
 
 Horizofi and locality. — In the sandstones and sandy shales of Assise 
 E. 2 (af), at Youngs point, near George river station, N.S. 
 
 The approximated central muscles and large widespread scars of the 
 anterior laterals of the dorsal valve in this species distinguish it from all 
 other Oboli, and from this and the peculiar grouping of the central group 
 of muscles, the trivial name is derived. 
 
 PAL^OBOLUS, sub-genus. 
 
 " Distinguished from Obolus proper by the close approximation of the 
 
 Pateobolus— vascular trunks, as shown by their impression on the ventral valve, and 
 
 how known, y^y ^{,g fof Ward direetiofi of its branches. The callus of the visceral cavity 
 
 of this valve is correspondingly narrow (therefore the muscle scars are 
 
 also approximated). Yet the talve is found as in OboluS." [Bull. Nat. 
 
 Hist. Soc. KB., Vo'. IV., p. 202.] 
 
U) 
 
 This sub-genus characterizes the Upper Etcbeminian Fauna. 
 
 The following is the original description of the species as published in 
 Bulletin XX. of the Natural History Society o New Brunswick. 
 
 Pal^obolus Bretonensis. pi. IX., figs. 2a to h. 
 
 " Oblately orbicular. Valves evenly rounded from the centre, except Palaeobolus 
 that the borders are flattened at the sides and front. Both dorsal and fe^cribld^' 
 ventral valves somewhat pointed at the umbo, which is depressed in both 
 valves. Interior of the ventral. — This ha.s a broad hinge area and a trian- 
 gular pedicle groove. The visceral cavity has two pairs of diverging 
 ridges, which mark the advance of the lateral muscles during the growth 
 of the shell. Between the outer and the inner pair originate the vascular 
 trunks, which in going forward throw oflf branches at an acute angle. 
 Interior of the dorsal valve. This valve has a broad, transversely striated 
 hinge area. The visceral cavity is traversed by two pairs of diverging 
 ridges, more widely divergent than those of the ventral valve ; there is 
 also a strong median septum along the middle of the valve. The central 
 group of muscle scars are about a fifth from the front of the valve. 
 
 "Sculpture. — The whole outer surface, except close to the umbo, is 
 ornamented with sharp concentric ridges which occasionally anastomose ; 
 these ridges have fine, faintly marked, radiating striae on their posterior 
 slopes, and are obscurely crenulated along their crests. 
 
 " Size. — Xieogth 15 mm., width 17 mm. Dorsal valve somewhat 
 shorter than the ventral." [Bull. Nat. Hist. Soc. N.B., Vol. IV., p. 
 202,] 
 
 The following are further particulars regarding this species. 
 
 Ventral interior. — The two pairs of diverging ridges extend across the Further 
 posterior third of the valve ; of these the outer pair divide ofi' the pos- th[s*s''pec!i° 
 terior lateral muscles, and the inner pair are directed toward the point of 
 attachment of the anterior laterals, to which they sometimes extend as 
 a border to the central callus ; in front of the callus on each side is a 
 depression, marking the place of the central group of muscle scars. The 
 vascular trunks in this valve run forward with a weak curve nearly to 
 the front of the valve ; the space between the trunks is about equal to 
 one third of the width of the valve ; beside the outer branches of the vas- 
 cular trunks referred to above, traces of internal branches are also found 
 towards the front of the valve. 
 
 Dorsal interior. — Of the two pairs of diverging ridges that traverse the 
 posterior third of the visceral cavity, the outer are longer than the inner ; 
 
142 
 
 the latter which extend forward about one-third of the length of the valve 
 from the umbo, are sometimes nearly doubled in length, and extend along 
 the side of the depression marking the place of the central scars. Bet- 
 ween the central scars a distinct septum is found, which begins opposite 
 where the two inner pairs of ridges, described above, usually terminate, 
 though sometimes it may be traced as far back as the hinge area. Where 
 this ridge fades out in front is a depression, marking the place of the an- 
 terior lateral muscles. The central group of muscle scars extends to about 
 one-fifth from the front of the valve. The vascular trunks in this valve 
 are as far apart as half of the width of the valve. 
 
 Sculpture. — The general aspect of the surface ornamentation is describ- 
 ed in the earlier publication above cited, the following are further par- 
 ticulars. For the first two millimetres from the umbo the ridges are very 
 minute, or are absent ; then outside of this they become visible with a 
 strong lens ; at from four to six millimetres from the umbo there are 
 about eight ridges in the space of a millimetre, and for the rest of the 
 shell about six to five, and finally four ; near the front of the valve the 
 ridges are lower, fainter and more closely set. The interior surface of 
 the valves in this species, often exhibit more or less irregular rows of 
 small pits ; the rows are in general concentric to the umbo, and give the 
 interior a rough appearance ; these rows are often found at the resting 
 stages in the growth of the shell, but other pits are miscellaneously dis- 
 tributed. 
 
 Size as given above 15 x 17 mm.; depth of two valves about 4 mm. 
 
 Horizon and locality. — In assise E. Zd of the Uppfer Etcheminian at 
 Dugald brook, Escasonie; also at Gregwa brook, Escasonie, N. S. 
 
 Except the following species, 0. lens, the Obolus nearest this age is (?) 
 major,Qi the Upper Etcheminian in New Brunswick; that species, however, 
 is large, and does not have the concentric ridges, on the only example of it 
 which is known. None of the European Oboli have the sharp ridges 
 which mark the surface of this species, and they all belong higher in the 
 geological scale. Obolus (Michwitzia) monilifera, Linrs., has a flattened 
 dorsal valve, and thus differs from this species, it is also distinguished by 
 its beaded surface. 
 
 This is the most noticeable brachiopod of the Upper Etcheminian 
 fauna, both for siz<5 and for the strong ornamentation of the valves. Like 
 Lingulepis Gregwa of the Lower Etcheminian fauna it seems to have 
 preferred a muddy bottom, as it is found to abound in the beds of Assise 
 d, which is more argillaceous than the assises above and below. 
 
143 
 
 The varying forms of the valves in the following table (and for other 
 species in other tables of this article) are largely due to the distortion of 
 the beds in which the fossils are preserved. This variation is corrected 
 by the average. 
 
 Valves of Obolus Bretonensis from Assise E 3 rf. (one from E. 3, a.) 
 
 — 
 
 I 
 
 1 
 
 i 
 
 Number. . 
 
 J3 
 
 t 
 
 Hi 
 
 
 i 
 
 a 
 
 mm 
 
 2 
 
 14 
 14 
 
 14 
 
 
 Resting Stages. 
 
 +3 
 
 -a 
 
 DS 
 
 U 
 
 1 
 S 
 
 H 
 mm 
 
 54 
 34? 
 
 
 
 1 
 
 2 
 
 3 
 
 mm 
 17 
 
 14 
 
 14 
 
 13 + 
 
 13 
 
 12? 
 
 13 
 
 104 
 
 12 
 
 mm 
 14 
 
 15 
 
 12 
 
 le 
 
 12 
 12 
 11 
 10 
 10 
 
 mm 
 
 . 8 
 
 7 
 8 
 
 7? 
 
 7 
 
 12 15 
 
 10 
 
 mm 
 
 14 
 14 
 
 Exterior, narrowed. 
 
 
 
 II narrowed. 
 
 
 4 
 
 8 
 
 
 I' 
 
 5 
 
 6 
 
 9 11 
 
 9J, 104 
 
 li 
 
 4 
 
 Interior. 
 
 
 7 
 
 8 
 
 9 
 
 94104 
 
 14 
 
 4 
 4 
 
 21 
 
 Interior, narrowed. 
 
 1 
 
 
 
 1 
 
 6i 
 
 
 
 Average . . 
 
 1 
 
 2 
 
 
 
 Assise E 3 a. 
 
 
 119 
 
 112 
 
 114 
 
 37 
 
 46 32 12 15 
 
 
 
 13-2 
 
 12-4 
 
 1-3 
 
 7-4 
 
 9-2,10-6,12-0,150 
 
 1-3 
 
 4-2 
 
 
 
 13 
 17 
 13 
 14 
 14 
 14 
 15 
 14 
 
 114 
 
 14-2 
 
 15 
 
 / 
 
 15 
 13 
 14 
 14 
 14 
 14 
 13 
 
 112 
 
 140 
 
 14 
 14 
 14 
 
 94 
 1-2 
 
 
 10 11 
 
 
 
 Exterior, broadened. 
 
 
 13 154 
 
 
 
 
 
 3 
 
 4 
 
 5 
 
 6 
 
 94 
 
 lot 
 
 11 
 9 
 
 40 
 
 100 
 
 9 104 
 
 
 
 II oblique. 
 Interior u 
 
 II mould of 
 
 1' 
 
 10 12 
 
 10 114 
 
 1 
 1 
 1 
 
 71 
 7 
 
 
 7 
 
 ....114 13 .... 
 
 
 
 8 
 
 Average 
 
 94 114 13 ... 
 
 
 6? 
 
 
 
 
 
 
 
 484 68 39 154 
 
 3 
 -10 
 
 204 
 6-8 
 
 
 
 9-7,11 -3, 13-0, 15-5 
 
 
 Dimensions 
 &o. of the 
 valves. 
 
144 
 'Obolus lens, n. sp. P). X., Figs, a to f. 
 
 (P^'fiis Shell rather thin and fragile, lenticular, nearly orbicular, with the 
 
 described, beak of the ventral slightly projecting. 
 
 Ventral valve with a depressed beak, slightly sloping sides, and usually 
 a depressed line, running along the mesian area. Interior, with a car- 
 dinal area about one-eight of the length of the valve. Within is a 
 visceral callus, extending a little beyond the middle of the valve, and 
 about twice as long as wide ; at the front is the scar of the central 
 muscles ; on the callus, two-thirds from the beak, is a shallow lance oval 
 depression. ] n front of the callus, but not always present, is a mesian 
 ridge, bordered by shallow grooves. Scars of the lateral muscles are 
 visible at the sides of the valve near the hinge line, outside of a long 
 vascular ridge. 
 
 The dorsal valve shows wide, flattened areas at the posterior lateral 
 slopes, and a narrow, widening, depressed band along the median line ; or 
 the centre i.s scarcely depressed, and there are two flattened ridges on 
 the valve diverging from the umbo, and about as far apart at the front 
 as one quarter of the length of the valve. Elsewhere the slopes of the 
 valve are regular. Interior. — This is imperfectly known. The visceral 
 callus extends beyond the middle of the valve, as is shown by the radi- 
 ating septa that cross the visceral cavity ; two of these ridges extend 
 nearly to the front of the valve. 
 
 Sculpture. — This consists of fine concentric ridges that sometimes run 
 together ; there are about eight of these ridges in the space of a millimetre, 
 and they are nearly regularly spaced except near the umbo ; there are 
 about twice as many of these ridges to the millimetre as in 0. Breton- 
 enais. 
 
 Size. — The ventral valve is about 14 mm. long, 12 mm. wide, and 1^ 
 mm. deep. The dorsal is about 1 mm. shorter than the ventral. 
 
 Horizon and locality. — In assises E. 3 6 and E. 3 e, (especially the 
 latter) of the Upper Etcheminian, Dugald brook, Escasonie, N.S. 
 
 This species is provisionally placed with the sub-genus Palseobolus. 
 though the vascular trunks are not so close together as in that species 
 (neither are they so wide apart as in the Obolus of Eichwald (Michwitz). 
 Though proportionately a narrower shell than the preceeding, this species 
 is evidently congeneric with it, and appears to replace it in the more 
 sandy beds of this zone. It can be distinguished from 0. Bretonensis 
 by the closeness of the concentric ridges on the surface of the valves. 
 The crests of these ridges are not beaded as in Obolus inonilifera, Linrs. 
 of the Swedish Cambrian. 
 
 The following table shows the size and main features of a number of 
 valves. 
 
145 
 Valves of Obolus lens from Assise B. 3e. 
 
 — 
 
 i 
 
 mm 
 
 1 
 2 
 3 
 4 
 5 
 6 
 
 rage. 
 1 
 2 
 
 3 
 
 4 
 5 
 
 rage. 
 
 mm 
 
 8 
 
 7i 
 
 7 
 
 7+ 
 11 
 
 94 
 
 50 
 8.3 
 
 10 
 11 
 10? 
 9? 
 11 
 
 51 
 
 10-2 
 
 ■3 
 
 •V 
 
 mm 
 6 + 
 
 I' 
 9 
 11 
 
 8 
 
 47 
 7-8 
 
 1] 
 11? 
 10 
 9 
 11 
 
 52 
 
 10-4 
 
 fl 
 
 mm 
 
 1 
 
 1 
 
 1 
 
 mm 
 5 
 
 Resting stages 
 of growth. 
 
 i 
 
 ja 
 5 
 
 1 
 
 1 
 
 
 A 
 
 
 
 
 mm 
 14 
 
 mm 
 
 4 
 
 Interior, mould cf 
 Exterior. 
 
 1 
 
 
 44 
 
 
 
 
 
 
 9 1 
 
 1 
 
 11 
 
 1? 
 H 
 
 5i 
 11- 
 
 7? 
 184 
 
 7^ 
 
 26i 
 6-6 
 
 
 
 
 
 
 Ave 
 
 164 
 5-5 
 
 64 
 
 8 
 
 8 
 '8- 
 
 8 
 
 94 
 
 ,94 
 9-5 
 
 1* 
 3 
 
 1-5 
 
 14 
 
 "4' 
 
 8 
 
 54 
 6? 
 6 
 6 
 
 Both valves. 
 
 Interior, mould of (on a slab). 
 
 Interior, mould of 
 Interior, exfoliated. 
 
 ?"S 
 
 
 
 
 14 
 
 
 ^} 
 
 64 
 6-5 
 
 "7 
 15 
 7-5 
 
 "9 
 9 
 9. 
 
 Interior. 
 
 Ave 
 
 14 
 
 234 
 5-9 
 
 
 Dimensions 
 &c. of the 
 valves. 
 
 Valves of Obolus lens from Assise E. 36. 
 
 - 
 
 1 
 1 
 
 
 4 
 
 -a 
 
 i 
 
 in 
 
 1 
 
 "hi 
 Q 
 
 Resting 
 stages of 
 growth. 
 
 1 
 
 "to 
 60 
 
 a 
 M 
 
 1 
 
 ■ a" 
 
 a 
 
 The dimensions are in millimetres. 
 
 
 1 
 2 
 
 11 
 10 
 
 10? 
 
 8+ 
 
 1 
 1 
 
 6? 
 
 
 2 
 
 6 
 
 Interior, exfoliated. 
 
 JS 
 
 
 Exterior. 
 
 u 
 
 
 
 2 
 
 6 
 
 
 S 
 
 21 
 
 18 
 
 2 
 
 6? 
 
 
 
 > 
 
 
 
 10-5 
 
 9 
 
 1- 
 
 6? 
 
 
 2- 
 
 6- 
 
 Average. 
 
 
 
 , 
 
 1 
 2 
 
 10 
 10 
 
 20 
 
 10- 
 
 8 
 9 
 
 17 
 
 1 
 1 
 
 
 6 8 
 
 7 9 
 
 Exterior, exfoliated. 
 Interior, mould of, widened. 
 
 
 P 
 
 2 
 
 
 13 17 
 
 2S 
 
 
 
 8-5 
 
 1- 
 
 
 6-5 8-5 
 
 1-4 
 
 
 Average. 
 
 Dimensions 
 of valves from 
 assise E 36. 
 
 10— C. R. 
 
146 
 
 Elsewhere we have noted the enlargement of the species of a genus in 
 passing upward from one fauna to another, as, for instance, Acrotreta. 
 A similar enlargement in size may be noted in Obolus. 
 
 Length. 
 
 Obolus torrentia, ColdbrooU terrane 7 to 8 mm. 
 
 0. triparilis, Lower Etcheiniman 8 to 9 i> 
 
 0. discus, Lower Etcheminian 10 " 
 
 O. sequiputeis, Lower Etcheminian 11 to 12 <i 
 
 0. lens, Upper Etcheminian 11 to 14 n 
 
 O. Bretonensis, Upper Etcheminian 14 to 17 n 
 
 Var. LONGUS, n. var. PL VII., Figs, ia and b. 
 
 l^ns-lon'^'s ■^'^^^ ^* ^""^^ ®^S'^'' ^PP^*'"=' quite distinct from Obolus lens, but has many 
 
 described. points in common. It has the form of an oval Lingulella, and the posi- 
 tion of the muscle sears of the ventral valve is lifke that of Lingulella 
 ovalis ; nevertheless the peculiar sharp, deep and long mesian furrow on 
 back of the dorsal valve, and the ornamentation of the surface of the 
 valves is so like that of Obulus lens, that we have concluded to place it 
 as a variety of that species. 
 
 The general form is lance-oval and the width two-thirds of the length. 
 Except in having shorter lateral vascular ridges, and in the difference of 
 proportion due to difference of form, this species doe? nit vary much from 
 the type. It has the same mesian ridge in the ventral and a similar de- 
 pressed longitudinal band on the dorsal. It has the shallow grooves 
 along the mesian ridge of the ventral valve that is apparent in some 
 examples of Leptoholus collicia. Its thin shell, weak cardinal area, flat- 
 tened mesian band on the dorsal, and straightened lateral margins are 
 Leptobolian characters ; but it has distinct and rather coarse concentric 
 ridges on its surface, while in Leptobolus this sculpture is fine and 
 close. Michwitz appears to have met with similar forms that he had 
 difficulty in placing as varieti 'S of Obolus (Schmidtia) obtusus. They are 
 of the Dictyonema Zone* 
 
 Sculpture. — This, consisting of close set concentric ridges, does not 
 differ from that of Obolus lens, except in being finer and closer. 
 
 Size. — Length of ventral, 16 mm. ; width, 10 mm. ; depth, about 1^ mm. 
 The dorsal is about 1 mm. shorter than the ventral. 
 
 Horizon ani locality. — Occurs infrequently in assise £. 3 e at Dugald 
 brook, Escasonie, N.S. 
 
 The following are dimensions of valves of this form : — 
 
 *Uber die Braohiopodengattung Obolus, Eiohwald, Mem. Acad. Imp. des Sci. St. 
 Petersb. Ser. viii., vol. iv., No. 2, Taf. ii., figs. 23-26 and 29-36. 
 
147 
 
 
 
 
 
 Valves of Obolus lens — longus from E. 3e. 
 
 — 
 
 1 
 
 1 
 
 2 
 3 
 
 1 
 2 
 
 1 
 
 1 
 
 i 
 
 1 
 
 Resting 
 stages of 
 growth. 
 
 1 
 
 1 
 1 
 
 llie dimensions are in millimetres. 
 
 1^^ 
 
 14 
 16 
 11 
 
 41 
 
 8 
 
 50 
 
 8 
 
 26 
 
 1 
 1 
 1 
 
 3 
 
 9 
 
 7 
 
 16 
 
 74 11 
 10 13 
 
 7 84 
 
 14 
 14 
 
 6 
 
 Exterior, narrowed (on a slab) 
 Interior, mould of 
 Exterior exfoliated 
 
 
 14J 294 13 
 
 3 
 
 6 
 
 
 
 13-7 
 
 10 
 94 
 
 8 7 
 
 1 
 
 8 
 
 7-2,9-8, 13 
 
 14 
 
 6 
 
 .Average. 
 
 II 
 
 8 
 
 7 
 
 1 
 1 
 
 .... 
 
 7 
 
 
 6? 
 
 Interior exfoliated 
 Exterior 
 
 (-1 ■ 
 
 
 
 
 
 
 
 19i 
 
 15 
 
 2 
 
 
 7 
 
 
 
 6? 
 
 
 
 9-7 
 
 7-5 
 
 1 
 
 
 7 
 
 
 G? 
 
 Average. 
 
 Dimensions 
 &c. of the 
 valves. 
 
 The following is a synopsis of the occurrence of Obolus in the Etche- 
 tninian strata of Cape Breton, and in the Coldbrook terrane of the same 
 island. 
 
 DiSTHiBCTiON of Obolus in the Coldbrook and Etcheminian terranes in 
 Cape Breton, N.S. 
 
 « 
 
 8 
 
 Etcheminian. 
 
 
 I 
 
 " 
 
 III 
 
 
 
 a 
 
 + 
 
 h 
 
 '+ 
 
 c 
 
 d 
 
 e 
 
 + 
 
 a 
 
 + 
 
 6 
 
 c 
 
 a 
 
 + 
 
 6 
 
 + 
 
 c 
 
 d 
 
 + 
 
 c 
 
 + 
 + 
 
 / 
 
 Obolus torrentis ■-.•. 
 
 + 
 
 
 
 
 
 
 
 
 
 
 
 
 O i Palsebolus^ ^retonetisis . 
 
 
 
 
 
 
 
 
 O ( - -) lens 
 
 
 
 
 
 
 
 
 
 
 
 Q 1 ) lens-longus -■•.* 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 
 Distribution 
 of Obolus in 
 the Basal 
 Cambrian. 
 
 lOJ— C. E. 
 
148 
 
 It will be seen that the Lower and Upper Etcheminian faunas are 
 each characterized by a special subgenus of Obolus, one having a peculiar 
 crowded arrangement of the central group of muscles of the dorsal valve, 
 the other having the vascular trunks unusually approximated in the 
 ventral valve. 
 
 Billmgsella 
 
 retroflexa 
 
 described. 
 
 Ornamenta- 
 tion of the 
 surface. 
 
 BILLINGSELLA, Hall & Clark. 
 
 BiLLINGSELLA RETROFLEXA, PL X., figS 2a 6. 
 
 This was described as a variety of Glitambonites plana, Pander. But 
 it has been found to belong to a much lower horizon than that species, 
 and to be, by its internal characters, a Billingsella. 
 
 The ventral valve is flat, except toward the umbo, which is elevated, 
 and for a short distance the shell has a convex slope on the back. 
 Interior. — The mould of an example from the sandy shale of Young point 
 shows clearly that this is not an Orthisina. The print of the adductors 
 extends forward a little more than a third of the length of the valve, and 
 is surrounded by a low ridge, connecting with the margin of the del- 
 tidium ; a slight emargination at the side of the imprint limits the 
 posterior adductor muscles. The print of the diductors extends far in 
 advance of that of the adductors — more than half as far again as these. 
 A lateral septum divides the diductors, and the posterior adductor is 
 bounded by an accessory lateral septum. In front of the print of the 
 adductors is a lanceolate depressed area, bordered by the minor pair of 
 trunks of the vascular system ; the outer pair of trunks turn outward 
 around the print of the diductors, going toward the cardinal angle. The 
 course of the branches of the vascular trunks is straight ; they are 
 numerous, but seldom fork ; their impression is faint beyond the outer 
 resting stage in the growth of the shell. 
 
 The dorsal valve is decidedly tumid in the middle portion, but curves 
 down quickly to the hinge line, where there is a low area. Interior. — 
 A mould of the dorsal shows that there was a median septum running 
 from the umbo nearly two-thirds of the length of the shell ; and on each 
 side of the ridge appear three radiating vascular furrows. At the hinge 
 line are the moulds of two short lateral plates, and at the centre of this 
 line, on the mould, a group of three pits due to the orurse and the car- 
 dinal process ; the latter is larger than the other two. 
 
 Sculpture. — The material collected last summer has thrown consider- 
 able light on the sculpturing of the valves, which is so different on the two 
 valves as to lead at first to the supposition that there are two species, with 
 difference in the coarseness of the ornamentation — one with ribs on the 
 
149 
 
 surface about as numerous as those described by Billings for 0. /esinata, 
 the other with much closer and finer ribs like 0. orientalis Whitfield. 
 But on sorting the valves into ventrals and dorsals it was found that the 
 valves with narrow ribs were ventrals, while those with wide ribs were 
 dorsals. It might be supposed that this peculiarity would prevent the 
 valves from fitting close together at the margins, but such a difficulty 
 could have been obviated by a special smoothing of the edges of the valves. 
 
 The diversity in the width of the ribbing is most marked in the middle 
 stages of growth ; in both the larval and senile stages the valves were 
 smoother. The spaces between the ribs in the dorsal valve are wider 
 than the ribs ; they are flattened and traversed by two, sometimes three, 
 low fine, slender, thread-like ridges, parallel to the main ridges ; on the 
 lateral slopes the spaces between the ribs have only one of these low 
 threadlike ridges. 
 
 This species has in the ventral valve 5 ribs in the space of 3 mm. and 
 the dorsal has four in the same space, counting the thread-like ridges as 
 well as the ribs. 
 
 5i2e— -Length of the ventral, 18 mm. ; width, 20 mm. ; depth at the 
 umbo, about 4 mm. The dorsal is about 2 mm. shorter and has a depth 
 of 4 mm. about the middle of the valve. 
 
 Horizon and locality. — The original examples were from a bed of gray Geological ag 
 sandstone at McFee's (Young point), near George river station. Cape *°^ locahty. 
 Breton, where it occurs with LinguleUa Seluryni and was collected by 
 Messrs. Weston and Robert, of the Canadian Geological Survey. The 
 species also occurs, but of smaller size, in the sandy shales that underlie 
 this sandstone. The sandstone in places is quite calcareous, and becomes 
 as coarse as a grit. The fossils are in the condition of casts that have 
 weathered out in this, now porous rock. These beds are tentatively 
 assigned to Assise E 2. a. of the succession in the gorge at Dngald brook. 
 
 BUlings described the dorsal valve of his species {B. festinata) as being 
 nearly flat. Such a description does not apply to B. retroflexa, in which 
 this valve has the usual convexity of an Orthid. But the ventral valve 
 is nearly flat, except near the umbo, though it slopes down to the hinge 
 line on each side, owing to the elevation of the umbo. 
 
 B. orientalis of Whitfield has close, narrow ribs in the ventral valve 
 (the dorsal is not known) like B. retroflexa, and might be compared with 
 laterally compressed examples of this species, but the print of the ad- 
 ductor muscles in that species is much larger than in this. 
 
 B. transversa Walcott is not unlike longitudinally compressed examples Compared 
 of this species (5. retroflexa), but the fine ribs between the coarse ones, species. 
 
150 
 
 figured for that species, while found on the dorsal valve of ours, do not 
 occur in the ventrals, and it is the ventral of his species that Mr. Walcott 
 figures ; however, ho describes the species as having very fine costse, 8 in 
 the space of 3 mm. ; our species has 4 or 5 in the same space, but young 
 shells may have 6. 
 
 Form. — The valves differ considerably in their proportions, but this 
 appears to be due to distortion after they were buried ; as now found, 
 the valves range from those in which the length and width are equal, to 
 others in which the width is a half more than the length. Taking an 
 average of a number of valves as shown in the accompanying table, the 
 width appears to be one-quarter greater than the length, but less than 
 this in the ventral valves. 
 
 Valves of Billingsella retroflexa from sandstone of E. 2 (ei !) at 
 
 at McFee's (Young point.) 
 
 (The dimensions in this table are in millimetres. ) 
 
 Ventral Valves. 
 
 Dorsal Valves. 
 
 — 
 
 i 
 
 .a 
 1 
 
 1 
 
 Hi 
 
 4 
 
 i 
 
 Resting 
 
 stages of 
 
 growth. 
 
 — 
 
 1 
 ^ 
 
 CUD 
 
 4 
 
 ■a 
 
 Mould of exterior 
 
 Interior 
 
 Mould of exterior 
 
 Dimensions of Mould of interior 
 
 the valves in 
 
 sandstone. Mould of exterior 
 
 Mould of exterior 
 
 1 
 2 
 3 
 4 
 5 
 6 
 7 
 
 18 
 17 
 12 
 16 
 15 
 14 
 15 
 
 20 
 20 
 14 
 21 
 19 
 20 
 23 
 
 5 
 
 12 14 
 5 10 14 
 5 8 10 
 
 Moulds of interior. . . ■! 
 Average 
 
 1 
 2 
 
 13 
 15 
 
 28 
 14 
 
 18 
 22 
 
 
 
 
 
 
 107 
 
 137 
 
 15 30 38 
 
 40 
 
 Average 
 
 153 
 
 19-6 
 
 5 10 13 
 
 ''0 
 
 
 
 The following are measurements of valves from the sandy shale below 
 the sandstone bed at Young point. 
 
151 
 
 Valves of Billingsella retroflexa from sandy shale at Young point. 
 (The dimensions in this table are in millimetres.) 
 
 Vbnteals. 
 
 
 DOBSALB. 
 
 
 — 
 
 1 
 1 
 
 } 
 
 .-2 
 
 Kesting 
 
 stages 
 
 of growth. 
 
 — 
 
 a 
 
 s 
 
 4 
 
 bo 
 a 
 
 J3 
 
 Resting 
 
 stages 
 
 of growth. 
 
 M'd. of interior. 
 
 1 
 
 m 
 
 14 
 
 4 8 11 
 
 Mould interior.. 
 
 1 
 
 11 
 
 14 
 
 7 10 
 
 ir exterior. 
 Exterior 
 
 2 
 3 
 
 4 
 
 11 
 
 loi 
 
 10 
 
 104 
 
 34 7410 
 
 6 8 
 4 6 9 
 
 II II 
 
 II exterior.. 
 
 II interior.. 
 
 2 
 3 
 
 4 
 
 12 
 11 
 12 
 
 16 
 14 
 13 
 
 74 94^. . 
 
 Uunensiona 
 
 II 
 
 . the sandy 
 8 11 shale. 
 
 Mould exterior. 
 
 5 
 
 10 
 
 14 
 
 
 II II 
 
 5 
 
 114 
 
 13 
 
 8 
 
 Young ,1 
 
 6 
 
 5i 
 
 6 
 
 
 II II 
 
 6 
 
 11 
 
 16 
 
 3 7 9 
 
 Mould of ,1 
 
 ( 
 
 11 
 
 16 
 
 
 11 II 
 
 7 
 
 11 
 
 12 
 
 34 8 10 
 
 
 
 
 
 
 II exterior. . 
 
 8 
 
 13 
 
 17 
 
 6 9 
 
 
 
 
 
 
 II II 
 
 9 
 
 10 
 
 17 
 
 7 
 
 
 
 744 
 
 82 
 
 114 274 38 
 
 
 102i 
 
 132 
 
 6i 584 58^ 
 
 Average 
 
 
 10-6 
 
 11-7 
 
 3-8, 6-9, 9-5 
 
 
 
 11-4 
 
 14-7 
 
 3-2, 7-3, 9-7 
 
 The greater proportionate width of the dorsal is due chiefly to its 
 shorter umbo. The shells in these shales are proportionately narrower 
 than those in the sandstone bed ; they are also much smaller, but the 
 difference does not seem to be specific. 
 
 Owing to the coarseness of the matrix both in the sandstone and the 
 shales, the finer details of surface ornamentation are obscured. 
 
 OSTRACODA. 
 
 OSTRACODA OP THE BaSAL CaMBEIAN ROCKS IN CaPE BrETON. 
 
 ' Investigations of the Cambrian rocks in Cape Breton has brought to Peculiarities 
 
 the writer's notice a number of new types of these small EntomostracanE^, ^ ^^^ , 
 
 •' '^ ' Ostracoda 
 
 and with the permission of the Director of the Canadian Geological of the BaeaJ 
 Survey, these were communicated to the Natural History Society of 
 Montreal, (See Can. Rec. Sci., Vol. VIII page 437.) 
 
152 
 
 The species all come from the Etcheminian sandstones and shales, and 
 from a body of shales included in the volcanic rocks which underlie 
 them. This part of the Cambrian appears to contain three faunas, one 
 in the shales of the volcanic rocks, and two in the Etcheminian sediments. 
 
 Only two species of Ostracoda have been found in the shales of the 
 volcanic rocks, so that the bulk of the fauna is Etcheminian. The dis- 
 tribution of the forms throughout this series of beds will be readily seen 
 by the accompanying table. The three larger divisions of the Etchemi- 
 nian shown in the table are lithological, and the Lower Etcheminian 
 Fauna is confined to the two lower divisions ; the Upper Fauna is in III 
 of the upper division. The letters beneath these divisional spaces indi- ' 
 cate the successive assises in which fossils have been found. No Ostra- 
 coda of the Protolenus Zone have been recognized in these beds, and so 
 it is supposed they are older than that fauna. 
 
 List of Ostracoda of the Ooldbrook and Etcheminian terranes in Cape 
 Breton with the horizons at which they are found. 
 
 Distribution 
 of the Ostra- 
 coda in the 
 Basal Cam- 
 brian rocks. 
 
 
 Names of species, 
 mutations and varieties. 
 
 i 
 
 o 
 O 
 
 Etcheminian. 
 
 
 I. 
 
 II. 
 
 III. 
 
 
 a 
 
 b 
 
 c 
 
 d 
 
 e 
 
 a 
 
 6 
 
 c 
 
 a 
 
 6 
 
 c 
 
 d 
 
 e 
 
 / 
 
 
 Leperdita (?) rugosa 
 
 
 
 / 
 
 
 
 
 
 
 X 
 
 X 
 X 
 
 X 
 
 
 X 
 
 X 
 
 
 s . 
 
 
 X 
 
 X 
 X 
 
 X 
 
 X 
 
 
 .1 
 
 n ti milt, maxima 
 
 
 
 
 X 
 
 
 ti It M magna 
 
 M n M major 
 
 II spectator 
 
 11 II Hiut. acuta 
 
 
 
 X 
 
 X 
 
 II II It spinosa 
 
 
 
 
 
 II II II sequata ... . 
 
 
 
 
 
 X 
 X 
 
 
 ^ 
 
 ■1 II var. benepuncta. . 
 
 !■ II mut. Isevis 
 
 II If II ligata 
 
 Bradoria scrutator 
 
 
 
 X 
 
 
 
 ,-: 
 
 II vigilans 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 a 
 
 II II mut. obesa, &c 
 
 
 
 X 
 
 X 
 X 
 
 X 
 
 
 
 
 
 
 
 
 
 
 II rugulosa 
 
 11 (?) ornata 
 
 
 
 
 
 
 Escaaona rutellum 
 
 
 
 
 V 
 
 
 11 (?) vetus 
 
 11 (??) ingens 
 
 Indiana oval is 
 
 X 
 
 
 
 
 X 
 
 X 
 
 
 
 
 
 
 
 
 X 
 
 
 
 
 X 
 
 
 
 
 
 
 
 11 lippa 
 
 '^ 
 
 
 Schmidtella (?) pervetus 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 X 
 
 X 
 
 7 
 
 ■" 
 
 
 II 11 mut. concinna. . . 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 
 
 
 
 (?) acuta 
 
 
 
 
 
 
 
 
 2 
 
 " 
 
 3 
 
 4 
 
 8 
 
 2 
 
 
 1 
 
 1 
 
 — 
 
 — 
 
 — 
 
 1 
 
 5 
 
153 
 
 The Ostracoda found in those deposits afford a means of discriminating Peculiarities 
 
 , 1 1 1 T^ 1 • 1 mi °° structure m 
 
 the layers, second only to the Brachiopoda. They are not nearly so num- the Ostracoda 
 
 erous as the latter, or they would be even more valuable in this respect, Cambriam 
 
 as they show considerable liability to variation. The forms of Bradorana 
 
 are specially abundant in the Lower Etcheminian strata, while Bradoria 
 
 and Schmidtella (?) are more common in the Upper. From their small 
 
 size these Ostracoda are easily overlooked, but their thick and strong 
 
 shells have resisted destructive agencies, and give examples that have 
 
 not suffered so much from distortion and pressure as some of the Bra- 
 
 chiopods. They possess some features of form and structure which are 
 
 peculiar. One notable feature is the position of the main muscle scar. 
 
 Mr. E. 0. Ulrich, who has given much attention to the study of the 
 
 Ordovician and Silurian Ostracoda seems to assume that the place for the 
 
 muscle is near the centre of the valve. At least he speaks of this as the 
 
 position of this mark in Leperditia* ; it is from the hinge to this point 
 
 that the sulcus or transverse groove extends in this genus. And if there 
 
 is any meaning in this connection in the central depression of the valve 
 
 a similar position for the muscle scar may be inferred for Primitia, Primi- 
 
 tiella, Isochilina, Kirkbya, Entomis and other genera. 
 
 But in the Etcheminian species of Ostracoda and in many of those of 
 the Protolenus Fauna of the St. John Group, we have not been able to 
 find any in which the muscle scar is so placed. On the contrary many 
 examples occur in which the scar holds an anterior position near the hinge 
 line. This peculiarity would have given greater mobility to the valves, and 
 it is a fact that while in many cases we find the valves spread somewhat 
 apart, there are others in which they are spread out flat and yet retain 
 their normal position of contact at the hinge line. 
 
 If there is any meaning in these furrows that extend from the hinge 
 as indicating muscular attachment there is a suggestion of a posterior 
 muscle, towards the posterior end of the cardinal line in the depression 
 that exists there in Beyrichona and Hipponicharion, and is faintly shown 
 in Escasona. But of such posterior muscle we have no sure evidence. 
 Of the anterior adductor muscle, however, there are plain indications on 
 the interior of many valves. 
 
 It is clear that Ostracods having such a radical difference of structure Peculiarities 
 from those of a later time, must have had different habits of life, °* ^labitat. 
 and among other peculiarities noted is that they usually occur solitary. 
 
 *Lower Silurian Ostracoda of Minnesota, p. 633. 
 
154 
 
 Seldom do we find any aggregations of individuals, and never the swarms 
 on a single layer of rock that may be f<. und in occurrences of the later 
 Ostracods ; hence they appear not to have possessed in any marked degree 
 the gregarious habit of these later genera. 
 
 Another peculiarity of the Etcheminian and Protolenian forms, as 
 distinguished from the prevalent Ostracoda of Ordovician and Silurian 
 Time, is the unusual convexity of the front moiety of the valve as com- 
 pared with the other. This for some time led the author to be uncertain 
 as to which was the anterior end of the valve in the genus Beyrichona. 
 He, however, low has no longer any doijbt, as the related genus Bradoria, 
 with its prominent ocular tubercle sets this matter at rest, and shows 
 that the thick end of the valves is the anterior one. 
 
 Another common feature is the prevalence of species which are as wide, 
 or wider than long. This peculiarity is connected with a long hinge 
 line and with more or less abrupt cardinal curves of the margin, 
 before these merge into the true anterior and posterior margins of the 
 valves (see Plate I. figs. 1 to 6, as & 6). When the angle at the lower end 
 of these cardinal curves is acute, a tubercle is sometimes developed, in 
 addition to that which marks the anterior and often the posterior end of 
 the hinge line (PI. I. fig. 13, a <fe c). 
 
 These laterally expanded valves are in a number of species somewhat 
 pointed at the lower margin, and in most the ventral margin is more or less 
 angulated (PI. XII. figs. 2, 3 and 6). It thus admits of division into two 
 portions which may be designated the anterior and posterior curves (« & d). 
 according to whether the part of the margin indicated is in front or 
 behind the ventral angulation. Sometimes the anterior curve of the mar- 
 gin will be stronger as in Beyrichona (Fig. 3) (and Escasona ? Fig. 6), 
 sometimes the posterior curve, as in Indiana (Fig. 1) and Bradorona (Fig. 
 2), is the stronger. In Hipponicharion (Fig. 4) the two are about equal. 
 
 Terms used in The cardinal curves (PL XII. figs. 2 etc., a and 6), extend from the 
 tbe^rOstfa- ^^''S^ ^^^^ along the margin until it becomes at right angles to the hinge, 
 coda. and they also vary greatly in direction and extent. Thus in Indiana 
 
 (Fig. 1) the posterior one is long, the anterior shorter ; in Bradorona 
 (Fig. 2) they are approximatively of equal length j in Beyrichona (Fig. 3), 
 sp. palpilio, the posterior one is almost obsolete, but in other species 
 (tinea, planata, etc.,) of this genus, it is well shown, and with these the 
 species of Escasona (Fig. 6) agree. In Bradoria (Fig. 5) both cardinal 
 curves, and especially the posterior, are well shown. In Hipponicharion 
 on the contrary these curves are almost obsolete. 
 
155 
 
 The relation of the muscle scar to the ocular tubercle is also a means of 
 discriminating the genera in these early forms of Ostracoda : thus in 
 Bradorona (Fig. 2) and Bradoria (Fig. 5) it is diagonally behind and below 
 the tubercle, but in Beyrichona it is below and somewhat in front of the 
 tubercle. In Hipponicharion (Fig. 4) the muscle print presses in 
 behind and below the tubercle. In Indiana (Fig. 1) the scar though not 
 well recognized appears to be as in Bradorona (Fig. 2). In Escasona 
 neither muscle scar nor tubercle have been certainly identified. 
 
 Comparing this group of genera with those of the Ordovician and Radically 
 Silurian, we note some obvious differences from them. Perhaps the most the Leperdi-"" 
 notable is the way in which the visual and muscular organs are crowded at 'i<J*- 
 the front end of the hinge. This would exclude them from the great 
 family of the Leperditidse, Jones, in which the muscle scar is near the 
 middle of the valve. The lateral expansion of the valves also is charac- 
 teristic, and still more the way in which a number are pointed at the 
 middle of the ventral margin. 
 
 We see no nearer relation in these species to the " zoe " group of giants 
 described by Barrande, than to the Leperditidse ; these remind one more 
 of the bivalve carapaces of Phyllopod crustaceans. The Canadian forms, 
 though many are above the average size of the fossil Ostracoda, are far 
 inferior in this respect to Aristozoe and its allies. 
 
 It seems to the writer that the position of the main adductor muscle 
 scar separates these species from all described Ostracoda, and he would 
 suggest for them the designation Bradoriidse, taking as types the genera 
 Beyrichona and Bradoria. Hipponicharion is widely divergent from the 
 others and in its strongly ridged surface simulates Beyrichia and may for 
 the present be placed in the family Beyrichidse. 
 
 Lepeeditia?? rugosa. pi. XII, fig. la to c. 
 
 (Can. Eec. Sci., Montreal, Vol. VIII., p. 443. 1902.) 
 This species may prove to be of another genus when more numerous Leperditia?? 
 examples are found. The single example found does not seem to justify ^g^bed 
 a final reference to any described genus. 
 
 Only the right valve is known and this is rather flat, and flattened 
 toward the hinge and the posterior slope ; its greatest convexity is in the 
 middle and the lower third. The outline is broadly oval, with a hinge 
 line half of the length of the valve. The anterior and posterior cardinal 
 curves are long; the posterior marginal curve and the lower side of the 
 valve are both somewhat straightened, and the anterior marginal curve 
 strongly rounded. 
 
156 
 
 There is an obscure ocular tubercule situated at the upper front angle 
 of the valve ; and an obscure, short and weak furrow behind it ; about 
 the middle of the cardinal line is a low, faintly marked tubercle. There 
 is a trace of a marginal furrow along the posterior margin. 
 
 Sculpture. — Corrosion of the surface has obscured the usual markings, 
 leaving a rough surface, which is crossed in several directions by broken 
 ridges, without regularity; except toward the lower margin of 'the valve, 
 where there are several sub-parallel to the margin. 
 
 Size. — This is the largest Ostracod obtained from the Etcheminian 
 terrane — Length 6| mm., width 5 mm., depth about 1\ mm. 
 
 Horizon and locality. — Assise E. 3. f. Upper Etcheminian, at Gillis', 
 Indian brook, Escasonie, N.S., scarce. 
 
 The flat form and wrinkled surface of this valve indicates a thin chi- 
 tinous test. It may have distant afiSnities with Isoxys, Walcott, but is 
 entirely different in form. It also approaches in outline Aristozoe rotun- 
 data Walcott,* but is of different relief. 
 
 BRADORONA. 
 
 Bradorona, 
 new sub- 
 genus. 
 
 The description of the genus Bradoria applies more particularly to the 
 smaller elongate forms, described in the Bulletin of 'the Natural History 
 Society of New Brunswick.! But beside these the Etcheminian beds 
 contain a group of larger forms, with similar ocular tubercule and muscle 
 scar, but broader and more triangular in form ; most of them belong to 
 the Lower Etcheminian Fauna but there are stragglers in the upper. 
 With their more angulated form they have the front marginal curve 
 straightened. These we propose to distinguish as a subgenus under the 
 name Bradorona. 
 
 Bradorona 
 
 Serspicator 
 escribed. 
 
 Bradorona perspicator. PI. XII,, fig 8a. to d. 
 
 (Can. Reo. Sci., Montreal, p. 444, 1902). 
 
 This is one of the largest Ostracods found in the Cape Breton Etche- 
 minian rocks and, if the following mutations are properly referred to it, 
 extends through them in varyinj,' forms and sizes. 
 
 In this typical form the hinge is more than thre:-fifths of the width of 
 the valves. The posterior cardinal curve is long and straight, the margin 
 bears a thread-like marginal fold on the left valve and there is a narrow 
 
 *Fauna of the Olenellus zone p. 627 pi. i. xxx fig. 3. 
 tBuU Nat. Hist. Soo. N. B. Vol. iv. p. 204 St. John 1899. 
 
157 
 
 obscure furrow, within the margin along the anterior and posterior mar- 
 ginal curves. The hinge margin is thickened, and a tubercle marks the 
 posterior end of the hinge line (of at least the right valve). The ocular 
 tubercle is distinct in each valve, behind which is a shallow furrow extend- 
 ing a short distance below it. There is also a short, obscure ridge extend- 
 ing obliquely downward from the ocular tubercle toward the lower margin 
 of the yalve. 
 
 The greatest convexity of the valve is two-fifths below the hinge line, 
 and the slope to the anterior margin is steep. 
 
 ScvJ/pture. In all the forms of this species obtained, the sculpture has 
 been obscured by corrosion, but remains of the cortex that have escaped 
 this destructive change show a pitted surface. By a linear arrangement 
 of the pits along the anterior and posterior slopes of the valves an appear- 
 ance of parallel ridges has been produced. 
 
 Size. Length 4f mm. Width 4 mm. Depth of each valve \\ mm. 
 
 Horizon and locality. This is of the Lower Etcheminian Fauna, and 
 occurs in Assise E. 1. d. at Dugald brook, Escasonie, N.S. — Frequent. 
 
 The following measurements exhibit some variations in size. 
 
 A right valve, length 4^ mm., width 4^ mm., depth IJ mm. 
 Another " " 4 " " 4| « " 1| " 
 
 A left " " 4 " " 4f " " l| " 
 
 Mutation maxima. PI. XIL, figs. 9. a, h. 
 
 Can. Rec. Sci. Montreal, Vol. VIII., p. 445, 1902. 
 This is the largest form of the species observed ; it is more rounded at Jlutation 
 the two ends and below, than the type, and is flatter, but is of the same described, 
 general form. 
 
 The hinge-line is two-thirds of the length of the valve. The posterior 
 cardinal curve is angulated. There is an obscure furrow behind the ocular 
 tubercle, extending half across the valve ; a low ridge extends along the 
 anterior margin, a little within it, and a fainter ridge along and near the 
 posterior cardinal curve ; a narrow marginal furrow is visible along the 
 anterior marginal curve ; an obscure row of tubercles extends along and 
 near the anterior half of the hinge of line. 
 
 Sculpture. Surface pitted, the spaces between the punctures becoming 
 anastomosing ridges near the margin, and presenting ridges on the pos- 
 terior half of the valve, sub-parallel to the margin. 
 
 Size. Length 6 mm., width 5 mm., depth of a valve If mm. 
 
158 
 
 Horizon and locality.- 
 brook ; scarce. 
 
 -Assise E. 1 c, Lower Etcheminian, at Dugald 
 
 Mutation 
 
 magaa 
 
 described. 
 
 Mutation 
 
 major 
 
 described. 
 
 Mutation magna, PI. XII figs. 11 » and h. 
 
 Can. Rec. Sci., Montreal, 1902, Vol. VIII., p. 446. 
 Valves rather tumid, hinge-line shorter than in the type, two-fifths of 
 the length of the valve ; ocular tubercle prominent, behind and around 
 it is a shallow furrow ; cardinal curves of the margin long. No marginal 
 furrow is visible. 
 
 Sculpture. Surface pitted ; there are obscure anastomosing ridges 
 between the pits parallel to and near the margin ; a narrow obscure 
 band extends from ocular tubercle obliquely backward and downward. 
 
 Size. Length, 5 mm. ; width, 4 mm. ; depth of a valve 1 J mm. 
 
 Horizon and locality. Assise E. 2 h, Lower Etcheminian, at Dugald 
 brook ; scarce. 
 
 Mutation majoe, PI. XII., figs. 10 a and h. 
 
 Can. Rec. Sci. Montreal, 1902, Vol. VIII., p. 446. 
 
 Valves rather tumid, hinge-line about three-fifths of the length of the 
 valve. Cardinal curves rounded ; no marginal furrows seen. Ocular 
 tubercle a little way from the hinge ; a broad obscure furrow behind it. 
 An obscure ridge runs from the posterior marginal curve to the anterior 
 middle of the valve, and thence curves up to the lower end of the anterior 
 cardinal curve. 
 
 Size. Length 5J mm. ; width 4J^ mm. ; depth of a valve \\ mm. 
 
 Horizon and locality. Assise E. 3 f.. Upper Etcheminian at Dugald 
 brook ; scarce. 
 
 Bradorona 
 
 spectator 
 
 desoribed. 
 
 Beadoeona spectatoe. pi. XII., figs. 12 a to ef. 
 
 Can. Rec. Sci., Montreal, 1902, Vol. VIII., p. 447. 
 
 This species is smaller than the preceding and has a more finely pitted 
 surface. The length and breadth of the valves are about equal. Length 
 of the hinge more than half that of the valve (?) ; the anterior and pos- 
 terior cardinal curves are about equal in length ; both anterior and pos- 
 terior marginal curves are convex. The upper part of the valve is most 
 protuberent as in Schmidtella. A sharp marginal furrow shows on some 
 valves. The ocular tubercle is prominent ; some examples show a short 
 
159 
 
 thread-like ridge extending diitgonaliy backward from the tubercle ; this 
 corresponds to a furrow on the inside of the valve. 
 
 Size. Length and breadth each 3^ mm. ; depth of a valve 1 mm. 
 
 Horizon and locality. In the dark, brownish gray sandy shale of Assise 
 E. 1 d. Lower Etcheminian, at Boundary brook, Escasonie, Rather 
 common. Also in Assises E. 1 6. and E. 1 . d. at Dagald brook ; infre- 
 quent. 
 
 Variety acuta. 
 
 Can. Eec. Sci., Montreal 1902, VoL VIII., p. 447. 
 
 This is a large form, more pointed below than the type. Anterior mar- Variety acuta. 
 ginal slope somewhat straightened. Ocular tubercle distinct. 
 
 Sculpture. Surface minutely punctuate, and showing a strong striation 
 near the hinge. 
 
 Size. Length and breadth each about 4 mm. ; depth of a valve 1 mm. 
 
 Horizon and loadity. Assise E. 1 b., Lower Etcheminian, at Dagald 
 brook ; infrequent. 
 
 A small example, supposed to be the young of this form is narrower, 
 more acutely pointed below, and with straighter anterior and posterior 
 marginal curve, was found in Assise E. 1 (f. at Boundary brook. 
 
 Mutation spinosa. PI. XIT., figs. 13 a and h. 
 
 Can. Eec Sci, Montreal, 1902, Vol. VTH., p. 448. 
 
 Wide below the cardinal curves. Anterior marginal curve straight- Mutation 
 ened. A sharp marginal furrow aU around except at the hinge. 
 
 The ocular tubercle is distinct and there are spines at the ends of the 
 cardinal curves, except at the lower end of the posterior curve. 
 
 Seidpture. The surface is minutely punctuate ; on the posterior slope 
 of the valves and on a band descending backward from the ocular 
 tubercle, the pits merge into interrupted striae, divided by inosculating 
 ridges. 
 
 Size. Length and breadth each about 4 mm. ; depth of a valve 
 1^ mm. 
 
 Horizon and locality. An entire carapace in the Assise E. 1 e., Lower 
 Etcheminian, at Dngald Brook ; scarce. 
 
160 
 
 Mutation 
 sequata. 
 
 Mutation jBQuata. PI. XTI., figs. 14 as and b. 
 
 Can. Eeo. Sci., Montreal, 1902, Vol. VIII., p. 448. 
 Anterior and posterior sides nearly equal. The form is oval, and is 
 wide below the cardinal curves, which are long. Anterior as well as 
 posterior marginal curve regularly arched. 
 
 Sculpture. The surface has been corroded, but shows traces of a minute 
 pitting. 
 
 Size. Length and breadth each 3f mm. ; depth of a valve 1 mm. 
 
 Horizon and locality. In Assise E. 3 d. Upper Etcheminian Fauna, 
 at Dugald brook. Rare. 
 
 Bradorona 
 observator 
 described. 
 
 Bradorona observator. PI. XII., figs. 15 a to c. 
 
 Can. Rec. Soi., Montreal, 1902, Vol. VIII., p. 448. 
 A small species of the same general form as the preceding, but the 
 anterior marginal curve is more oblique on the hinge line, the ventral 
 angle being opposite to the posterior half of the cardinal line ; this 
 (2 mm. long) is considerably more than half the length of the valve. 
 
 The anterior cardinal curve is angulated at each end ; the posterior is 
 a third longer than the anterior. The anterior marginal curve is 
 straightened and is considerably longer than the posterior, which is 
 strongly arched outward. A narrow thread-like marginal fold is visible 
 in some places. A thickened band within the margin, in some places, 
 shows slight protuberences. 
 
 Sculpture. In most examples the surface is scabrous from corrosion, 
 but some show traces of a minute pitting, and near the margins of the 
 valve these pits form continuous rows, or furrows. The mould of the in- 
 terior showing smooth surface having minute punctures. The muscle scar 
 behind the ocular tubercle, is distinct on the mould of the interior of the 
 valve. 
 
 Size. Length 3^ mm ; width 3 mm ; depth of avalve 1 mm. 
 
 Horizon and locality. In Assise E. \. d.. Lower Etcheminian, at 
 Boundary brook. Common. 
 
 The following are measurements of several valves from this locality : 
 
 Left valve, length 'i\ mm., width 2\ mm., depth 1 mm. 
 
 Carapace 
 
 3i 
 
 If 
 
 (t 
 
 3 
 
 H 
 
 (( 
 
 u 
 
 2f 
 
 3i 
 
 U 
 
 (( 
 
 2f 
 
 3f 
 
 it 
 
 (( 
 
 2| 
 
161 
 
 Three forms which may be classed as varieties of this species are the 
 following ; 
 
 Variety benkpuncta. PL XII., fig. 16. 
 
 Can. Rec. Sci. Montreal, 1900, Vol. VIII., p. 449. 
 Anterior cardinal curve longer than the posterior ; anterior marginal Variety 
 curve straightened and the greatest width of the valve posterior to the descnb^. 
 middle. Hinge-line nearly half of the length of the valve (2^ mm). 
 Ocular tubercle distinct ; a shallow furrow behind and below it. A faint 
 ridge extends forward from the posterior end of the hinge half way to the 
 furrow below the ocular tubercle. Another example, more oval and more 
 tumid, has an obscure row of tubercles arching outward and forward 
 from the posterior cardinal angle to the anterior cardinal curve. A low 
 ridge extends back from the ocular tubercle to the hinge. 
 
 Sculpture. The surface is corroded, but on the posterior slope of the 
 valve are anastomosing ridges parallel to the margin. 
 
 Size. Length, 4J mm. ; width, 3J mm. ; depth of a valve, 1 mm. A 
 carapace from this locality had length 4J mm ; width, 3J mm ; depth of 
 the two valves, 3 mm. 
 
 Horizon and locality. Assise E. 1. d., Lower Etcheminian, at 
 Boundary brook. Scarce. 
 
 Mutation LjEvis. 
 
 Can. Rec. Sci. Montreal, 1902, Vol. VIII., p. 450. 
 Oval, cardinal curves long, the anterior one rounded. Hinge line more Mutation 
 than half the length of the valve (^), a tubercle at the posterior end. described. 
 Ocular tubercle off from the hinge-line and prominent ; ocular furrow 
 shallow. The right valve has a thread-like marginal fold ; no fold on the 
 posterior slope of the left valve. 
 
 Sculpture. Punctuation fine, showing anastomosing ridges near to and 
 parallel to the posterior slope of the valve. An example from the higher 
 horizon shows a thickened band near the margin along the posterior 
 marginal slope, that bears obscure elongated tubercles. An example of 
 the mould from the same horizon has three small pits behind the ocular 
 tubercle, parallel to the hinge. 
 
 Size. Length, 4J mm ; width, 3J mm ; depth 1 mm. 
 
 Horizon and locality. Occurs in assises E. \. h, and E 2 c, Lower 
 Etcheminian, at Dugald brook. 
 
 11— c. R. 
 
162 
 
 The following are measurements of examples from the two.horizons : 
 
 E. 1. b, carapace, length, 4 mm. ; width, 3 mm. ; depth, 2J mm. 
 II . II (I gi i< II 3 II If '[l^ <• 
 
 E. 2c, right valve " 4J « " 3^ " " 1 
 
 Mutation 
 ligata. 
 
 Mutation ligata, PI. XII., fig. 17. 
 
 Can. Rec. Sci. Montreal, 1902, p. 461. 
 Oval, cardinal curves long, anterior marginal curve straight, posterior 
 ornamented with a row of small tubercles ; a similar row extends direct 
 from the lower end of the posterior cardinal curve toward the lower end 
 of the valve, near which it curves forward. Ocular tubercle obscure, it 
 appears to be represented by four small tubercles ; but the furrow is well 
 marked. 
 
 Sculpture. The punctation is rather coarse, and there are anastomos- 
 ing ridges near the two ends of the valve, parallel to the margin. 
 
 Size. Length 4 mm. ; width 3 mm. ; depth of two valves, 2 mm. 
 
 Horizon and locality. Assise E. 3. e., Upper Etcheminian, at Dugald 
 brook, Escasonie, N.S. Rare. 
 
 BRADORIA* 
 
 Genus 
 Bradoria. 
 
 Named for the Bras d'Or, a salt water lake occupying the interior of the island of 
 Cape Breton. 
 
 "In the Protolenus Fauna are two species of Ostracoda which, for want 
 of other known relationship, were referred to the genus Primitia. It 
 would appear now that they are representatives of an ancient type of 
 crustaceans which has species in the Etcheminian Fauna. Though hav- 
 ing the general form of Primitia, Primitiella and Aparchites, they do not 
 have the median pit, or sulcus of the first, the shallow median depression 
 of the second, or the smooth valve of the third. Their most marked 
 character is a prominence or tubercle at the front of the hing-line. From 
 the smoothness of the summit of this tubercle, and its advantageous posi- 
 tion for vision, it is suppospd to be an ocular tubercle. Some of the species 
 have, close behind this tubercle, a short vertical furrow ; or the furrow may 
 pass around the tubercle. In the five species referred here the marginal 
 furrow is obscure, or in side-view along the lower margin, invisible. 
 
 The known species are of nearly the same size — about 3 to 4 mm, long— 
 and the surface of the valves is distinctly pitted, tuberculated or wrinkled. 
 
 *Nat. Hist. Soo. N. Brunswick, Bull. vol. iv., p. 204. 
 
163 
 
 The following are the species which fall under this genus : Primitia ocu- 
 lata and P. aurora of the Protolenus Fauna and the following species " : 
 
 Beadoria scrutator, pi. XIII., figs. 1 o to c. 
 
 Bradoria scrutator, n. sp. Nat. Hist. Soc. N.B. BulL vol. iv., p. 204, pi. 
 
 iv., figs. 1. a to c. 
 
 Can. Rec. Soi. Montreal, 1902, p. 452. 
 " Outline of the valves ovate, with a straight hinge-line. Hinge-Hne Bradoria 
 more than half the length of the valve, terminating in front at a short original ' 
 transverse furrow, situated immediately behind the tubercle. The hinge description, 
 is bordered all along its course by a narrow sharp ridge, similar to a mar- 
 ginal ridge. The tubercle is nearly marginal, and is situated just in front 
 of the hinge-line. In front of it the margin of the valve turns downward 
 and is bordered by a narrow, obscure furrow, which extends around the 
 ventral margin of the valve. There is a slight angulation of the outline 
 of the valve at the middle of the anterior border, separatiiig there the 
 cardinal and anterior curves. The posterior margin rounds regularly up- 
 ward behind to the hinge-line. 
 
 Sculpture. (1) The whole surface of the valve is covered with closely set, 
 rather coarse, conspicuous pits that are finer toward the hinge where they 
 have a linear arrangement." On the posterior half, toward the posterior 
 margin, the tubercles between the pits have a tendency to coalesce, and 
 thus produce obscure ridges whose course is directed toward the lower 
 border of the valve. 
 
 Size. Length, 3 mm. ; width, 2^ mm. ; depth, 1 mm. 
 
 Horizon artd locality. Assise E. 3. c. Upper Etcheminian, at Dugald 
 brook, Escasonie, N.S. 
 
 Additional material shows much better the characters of this species. Additional 
 In this the valves have been of a more distinctly oval form than in those "^ ^^^ '^' 
 oi^Bradorona observator, the cardinal curves being rounded so that the 
 straightening of the anterior marginal curve alone defines the length of 
 the cardinal curve above it. The posterior cardinal curve is rounded to 
 the hinge, and the lower edge of the valve is broadly rounded. 
 
 Sculpiure. (2) The interior shows a large muscle scar near the hinge- 
 line, behind the ocular tubercle; and also an unusually long straight 
 groove, directed backward and downward, in front of the tubercle ; a 
 fainter, shorter groove directed toward the anterior margin lies in front 
 of this. A thickened' band of the shell substance, making a slight ridge 
 11|— C. R. 
 
Compared 
 with other 
 species. 
 
 164 
 
 on the inner surface, extends from the posterior cardinal angle, around 
 the ventral slope of the shell to the anterior marginal curve. The 
 following are measurements of some valves : — 
 
 Left valve, length 3mra. ; width 2J mm. ; depth 1 mm. 
 Right " " 3J " " 24 " " 1 " 
 
 (c (c It Q (I (( 24- ^* ^* 14> " 
 
 Carapace " 2f " " 2 " "2 " 
 
 As compared with the species of the Protolenus zone — this species is a 
 little larger than B. oculata, from which it is easily distinguished by the 
 character of the surface ornamentation ; in the Etcheminian species the 
 pits are coarser and closer together, and it thus has a rougher surface 
 than the species above named. The sculpturing is more like that of 
 Isochilina ventricosa, which, however, is a much larger species. P. aurora 
 of the Protolenus zone is nearly of the same size, but it differs in the 
 strong anterior furrow, and in its finely pitted surface. 
 
 Bradoria 
 vigilans. 
 
 Compared. 
 
 Bradoeia vigilans. pi. XIII., figs. 2 a to c. 
 
 Bradoria vigilans, n. sp. Nat. Hist. Soc. N. B. Bull, vol. iv., p. 205, pi. 
 
 iv., figs. 2 a to c. 
 
 Can. Rec. Soc. Montreal, 1902, p. 454. 
 
 Outline of the valves ovate, somewhat pointed behind, moderately 
 arched transversely, the valves somewhat ridged lengthwise. The right 
 valve has a hinge-line about half of the length of the valve, which is 
 flattened down at the hinge forming there a lance oval area. There is a 
 prominent tubercle at the front of the hinge surrounded by a shallow 
 groove. The margin is gradually rounded from the front, and projects 
 somewhat at the posterior end, whence the posterior cardinal curve goes 
 directly upward to the back of the hinge. 
 
 Sculpture. The surface is marked by close set granulations, that 
 become finer toward the hinge-line and the ocular tubercle ; at the pos- 
 terior quarter of the valves the granulation graduates into a series of sub- 
 parallel anastomosing ridges. 
 
 Size. Length 3J mm. ; width 2J mm. ; depth f mm. 
 
 Horizon and locality. Pound in Assise E. 3 e. of the Upper Etche- 
 minian, Dugald brook, Escasonie, Cape Breton, N.S. 
 
 " Distinguished from Aparchites conchijormis of the Protolenus Fauna, 
 by its smaller size and prominent tubercle ; and from A. secunda by the 
 tubercle and the coarser ornamentation," as well as by the angulated 
 projection at the end of the valve. 
 
165 
 
 An additional example of this species from the bed in which the 
 original was found, and three others from a layer about a foot lower in 
 the measures, give additional information of the species. 
 
 These examples are wider than the type. The ocular tubercle in this 
 species is a little off from the hinge-line. The cardinal slopes are long 
 and the anterior marginal slope is somewhat straightened. 
 
 The following are measurements of some valves : 
 
 right valve, length 3 J mm., -width 2 J mm., depth ^ mm. Dimensions 
 
 (C (C 
 
 
 H 
 
 
 t( (C 
 
 
 3 
 
 
 tl (C 
 
 
 3 
 
 
 <( (( 
 
 
 H 
 
 
 carapace 
 
 
 3 
 
 Mutations 
 
 2i •' 
 
 " 1 " 
 
 2 " 
 
 « 1 " 
 
 2J " 
 
 « 1 " 
 
 n " 
 
 ■' 1 " 
 
 2i " 
 
 " 2 " 
 
 In the lower Etcheminian Fauna some forms occur which may be 
 referred to this species as mutations. 
 
 Assise E. 1 h. mut. obesa. 
 
 Can. Rec. ScL Montreal, 1902, p. 455. 
 
 A broader and more tumid form than the type. The hinge-line is Mutations of 
 three-fifths of the length of the valve and there is a tubercle at the pos- ^ specie?, 
 terior end of the hinge line. The ocular tubercle is prominent and 
 enclosed by the furrow ; a row of low and obscure tubercles runs curving 
 from the ocular tubercle to the lower angle of the valve. 
 
 Sculpture. The surface is marked by a fine punctuation, and by anas- 
 tomosing ridges on the posterior half of the valve ; a diagonal band of 
 these ridges runs from the ocular tubercle, diagonally backward and 
 downward to the lower part of the anterior margin. 
 
 Size. Length 3 mm., width 2^ mm., depth two valves together 1 J mm 
 or more. 
 
 Assise E 1. c. A form occurs here which is flatter than the preceding 
 and smaller. 
 
 This form differs from the young of Bradorona observator of the lower 
 fauna in the deeper furrow around the tubercle, and in the rounder base 
 of the valve ; henne we have associated it with £. vigilans. 
 
166 
 
 Assise E. 1. d. An imperfectly preserved right valve was obtained 
 here from beds of feldspathic sandy shale. It is considerably smaller 
 than the type, and the surface is rough and dull from corrosion. 
 
 Size. Length of a valve 2^ mm., width If mm., depth ^ mm. 
 
 Bradoria 
 rugulosa. 
 
 Bbadoria rugulosa, pi. XIII, figs. 3 a to d. 
 
 Bradoria rugulosa, n. sp. Nat. Hist. Soo. N. B. 
 Bull, iv, p. 205, pi. in, figs. 3 a to d. 
 
 Can. Reo. Sci. Montreal, 1902, p. 456. 
 "A suborbicular species of which only the right valve is known. 
 Tubercle rather prominent, some distance below the anterior end of the 
 cardinal line ; this line is nearly straight and about half of the length of 
 the valve. There is a faint furrow behind the tubercle. A narrow 
 obscure marginal rim appears at the back of the valve. 
 
 Sculpture. The lower slope and the posterior half of the valve are 
 covered with anastomosing ridges, concentric to the upper front part 
 of the valve j toward the top and front of the valve these ridges become 
 obscure and the surface of the valve is granulated. 
 
 Size. Length 2f mm., width 2J rnm., depth less than J mm. 
 
 Horizon and locality. In assise E. 3 e.. Upper Etcheminian Fauna^ 
 Dugald brook, Escasonie, Cape Breton, N.S. Rare. 
 
 " This little species is easily distinguished from others of the genus 
 by its orbicular form and ruguloae surface which is like that of certain 
 trilobites." 
 
 Mutation. 
 
 A small right valve of the form of this is found in Assise E. 1 c Lower 
 Etcheminian, at Dugald brook. The punctuation is fine and distinct, and 
 the rugulose surface is seen only near the margin of the valve. 
 
 Bradoria (?) 
 ornata. 
 
 BbADOEIA ? ORMATA, PI. XIII, figs. 4 a to c. 
 
 Can. Reo. Soi. Montreal, 1902, p. 456. 
 
 The valves in this species are rather flat and are rounded to the hinge 
 and lower margin, but not much to the ends. 
 
 Only one example known, which is supposed to be a right valve. 
 
 Suboval with a long hinge-line, about three quarters of the length of 
 the valve. Anterior cardinal curve short, posterior longer. Anterior 
 marginal curve long, rounded ; posterior shorter, rounded forward. The 
 
167 
 
 valve is more tumid in the cardinal third, and rounded to the hinge, 
 where there is a low narrow ridge. A thread-like marginal fold is visible 
 in some parts of the margin. 
 
 In this species there is no definite ocular tubercle, but a group of sev- 
 eral small tubercles on a slight elevation, occupy its place. The ocular 
 furrow is shallow, and close to the front of the hinge, and extends down- 
 ward opposite the anterior cardinal curve. 
 
 Sculpture. — The sudrface is covered with distinct pits, the spaces bet- 
 ween which become inosculating ridges, subparallel to the length of the 
 valve, but tending downward in the direction of the front of the valve ; 
 towards the hinge line the pitting is very minute. 
 
 Size. — Length 2\ ram., width, 1 J mm., depth of a valve nearly J mm. 
 
 Horizon and locality. — Assise E. 1 c. Lower Etchemiuian Fauna, at 
 Dugald brook, Escasonie, N.S. 
 
 The sculpture, something like that of an Entomis or a Kirkbya but 
 finer, seperates this little species from the others. 
 
 ESOASOJSTA.* 
 
 Can. Rec. Soi., vol. VIII., 1902, p. 157. 
 A few forms which cannot be referred to any described genus of the Genus 
 Eopalsezoic are present at two horizons in the Etclieminian. The typical ^c^fo""- 
 form is in one of the highest beds of the Upper Etcheminian. It is short 
 and high and the slight eminence which appears to indicate the ocular tu- 
 bercle is close to the hinge. There is a long slope from the hinge toward 
 the middle of the valve ; it thus resembles Beyrichona ; but it does not 
 have the two strong furrows or pits near the hinge which characterize that 
 genus ; nor is the slope from the hinge so long. Though tumid in the 
 upper third of the valve, this form cannot be classed with Schmidtella, 
 because the slope in the upper third of the valve is not bent down 
 abruptly to the hinge, as in that genus ; and furthermore the outline of 
 the valve is that of Beyrichona and Bradorona, and not the round valve 
 of Schmidtella. I refer to this genus Beyrichona ovata of the Protolenus 
 fauna. The typical characters of the genus are in the first of the follow- 
 ing species, E. rutellum. 
 
 ESCASONA RUTELLDM. PI. XIII, figS. 5 a to C. 
 
 Can. Rec. Sci. Montreal, 1902, p. 458. 
 
 A broad tumid species. Hinge two-thirds of the width of the valve. Escasona 
 Anterior cardinal curve obsolete ; posterior one-half of the length of the mtellum. 
 
 * Named for the district of Escasonie in Cape Breton. 
 
168 
 
 hinge, anterior marginal curve long, arched; posterior shorter, nearly 
 straight, lower end of the valve obtusely pointed. 
 
 Highest point of the valve one-third from the hinge and two-fifths from 
 the posterior margin. The ocular tubercle is small, close to the hinge and 
 some distance from the anterior end. The posterior slope of the valve is 
 flattened. The cardinal slope of the surface of the valve has a broad 
 shallow furrow extending down nearly to the highest part of the valve. 
 The arched anterior sloped surface of the valve is evenly curved down to 
 the border. 
 
 Sculpture. — The surface of the shell has been corroded, and the pitted 
 surface is obscure. 
 
 Size.— Length, 3 mm.j width, 3f mm.; depth, IJ mm. 
 
 Horizon and locality. — Assise E. 3/, Upper Etcheminian, at Gillis' 
 Indian brook, Escasonie, N.S. Scarce. 
 
 Escasona (?) 
 vetus. 
 
 EscASONA (?) VETUS. PI. XIII, figs. 6 a and h. 
 
 Can. Rec. Sci. Montreal, 1902, p. 458. 
 
 This form, represented by a right (?) valve, has a more rounded surface 
 than the type, and the valve is flatter. No ocular tubercle is determin- 
 able. The hinge line is very long (sixth-sevenths of length) and there is 
 a shallow furrow extending from it on the cardinal slope of the valve. 
 The valve is most tumid toward the posterior (?) side ; and the ventral 
 angle is vertically behind the end of the cardinal line. A broad thick- 
 ened band runs around the supposed posterior margin. 
 
 Sculpture. — The shell is minutely pitted, but it is mostly decorticated. 
 
 Size. — Length, 3 mm. ; width, 3^ mm. ; depth, f mm. 
 
 Horizon and Locality. — Assise E. 1 d. Lower Etcheminian, at Boun- 
 dary brook, Escasonie, N.S. 
 
 Escasona (??) 
 ingens. 
 
 Escasona (??) ingens, PI. XIII. figs. 7 a to c. 
 
 Can. Rec. Sci., Montreal 1902, p. 459. 
 
 Only one valve known. The unusual form agrees with none of the 
 other genera of the Etcheminian Ostracods. It appears to be a left valve 
 and is so described here. The outline is obliquely subtriangular and 
 somewhat wider than long. 
 
 The hinge line is three-quarters of the length of the valve; a shallow 
 furrow runs parallel to the hinge, and near it for two-thirds of the length 
 
169 
 
 of the valve. No ocular tubercle could be detected, but at what appears 
 to be the posterior upper angle of the valve is a small tubercle. The 
 anterior cardinal curve is short and nearly in the direction of the hinge ; 
 the posterior is wanting. The anterior marginal curve is long and strong- 
 ly arched ; the posterior is shorter and less arched, abruptly rounded 
 below, and at a right ans^le with the hinge line. The valve is highest at 
 the middle, gently arched toward the hinge, and to the lower margin of 
 the valve, and more abruptly towards the anterior margin. A faint ridge 
 or swelling runs along the back of the valve near the margin. Lower 
 angle of the valve bluntly rounded. Traces of a narrow marginal fold 
 are preserved in some places. 
 
 Sculpture. — The surface is corroded, and only in a few places can a fine 
 punctation be seen. 
 
 Size. — Length, 6 mm. ; width, 6J mm. ; depth, IJ mm. 
 
 Horizon and Locality. — In a fine gray shale, containing grains and 
 lumps of calcium phosphate, included in the Coldbrook volcanic rocks at 
 Dugald brook, Escasonie, N.S. Scarce. 
 
 This ancient Ostracod has the outline of a Beyrichona, but there is no 
 flattened cardinal area of the valve, nor any trace of the deep muscle-pit 
 of that genus. It is separated from Bradoria by the absence of ocular 
 tubercle and posterior cardinal slope. It is provisionally placed in Esca- 
 sona, though lacking the high elevation of the cardinal third of the valve, 
 peculiar to the other species of that genus. 
 
 INDIANA.* 
 Can. Kec. Sci., vol. VIII.. 1902, p. 460. 
 
 Two forms of Ostracods of the Etcheminian Fauna difier from any of Genus 
 the proceeding by their marked oval form and do not seem to fall into '*"*■ 
 any of the later genera. The author has heretofore referred resembling 
 forms to Aparchites and Primitia, but omitting from consideration the 
 large size of most of the Basal Cambrian species, they also have usually a 
 well developed ocular tubercle, or the rudiments of one. 
 
 In a decorticated example there is a faint muscle mark, where the mus- 
 cle scar is placed in Bradoria and Bradorona, but it projects less toward 
 the middle of the valve than in those. 
 
 The genus consists of large to medium-sized Ostracods, oval or ovate 
 in form, the outline somewhat straightened e^cng the hinge,somewhat 
 sharply rounded at the anterior end, more broadly at the posterior. A 
 ventral angle is scarce traceable, and the greatest fulness is in the post- 
 
 * Named for the Indian brook, on the branches of which these fossils were found. 
 
170 
 
 Specie 
 referred to it. 
 
 Distinguished 
 from other 
 genera. 
 
 erior half of the valve. The valves are evenly rounded, and highest about 
 the middle. An ocular tubercle, or traces of one, can usually be seen in 
 the upper anterior region of the valve. 
 
 Length of the known species, 3 to 6 mm. 
 
 Range. — Through the Etcheminian and Protolenus Faunas. 
 
 Besides the species described below the following appear to belong here ^ 
 
 Primitia pyriformis. t ) Both of the 
 
 P. (?) fusiformis. * ) Protolenus Pauna. 
 
 Aparchites (?) robustus t also of that fauna comes near this group. 
 
 This genus is seemingly different from Nothozoe of Barrande. Nothozoe 
 is an oval fossil occurring in the Ordovician of Bohemia, which the above 
 author has referred doubtfully to the Ostracoda. The size, however, is 
 much greater than that of the fossils we are dealing with here:{:and no 
 ocular tubercle has been recognized. For these reasons, as well as on 
 account of the obscurity of the characters of Nothozoe, it seems inadvi- 
 sable to use this name for the Etcheminian species described below. 
 
 Equal objections may be taken to the referring of the Cape Breton 
 species in question to the genus Primitia, or to Aparchites, which hitherto 
 the author has used for the Lower Cambrian forms. The species of these 
 genera are small, and the absence of an ocular tubercle in one, and the 
 presence of a median sulcus in the other, are further distinctions from 
 the species which the author has referred to Indiana. Few species of the 
 genera Primilia and Aparchites attain a size in which the area of the 
 valve is a tenth that of the shells referred to this genus. 
 
 Indiana 
 ovalis. 
 
 Indiana ovalis. PJ. XIII, fig. 8 a to c. 
 
 Can. Reo. Soi., Montreal, 1902, p. 461. 
 
 This species is ovate, broader behind than in front. Hinge line about 
 one half of the length of the valve. Cardinal curves of moderate length. 
 Anterior marginal curve long, arched ; posterior short, more strongly 
 arched. No marginal furrows seen. Ocular tubercle close to the hinge 
 line ; a narrow diagonal furrow behind the eye, extends to the lower end 
 of the anterior marginal curve. 
 
 Sculpture. — Along the lower margin are fine anastomosing ridges ; the 
 decorticated part of the valve shows the lower margin of- a semi-circular 
 muscle scar, directly behind the ocular tubercle, near the hinge line. 
 
 t Roy. Soo. Can. Trans., vol. iv, sec. iv, p. 132, pi. i. fig. 3 a to c 1 and 4 a to c. 
 * N.Y. Acad. Sci., Trans., vol. xiv, p. 237, pi. vii, figs. 3 a and h. 
 t Individuals of Nothozoe pollens (-'yst. Silur. Bohm, vol. i, Supp. p. 536 have an area 
 of valve 70 times greater than the largest species of Indiana. 
 
171 
 
 Another example of the valve with the surface somewhat corroded shows 
 small pits and also anastomosing ridges on the surfrce. 
 
 Size. — Length, 4J mm. ; width, 3;^ mm. ; depth of a valve, 1 mm. 
 Another example is 3J mm. wide. 
 
 Horizon and locality. — Assise, E. 1 e. Lower Etcheminian at Dugald 
 brook, Escafionie, N.S. Scarce. 
 
 A form similar to this in size, though proportionately wider, occurs in 
 the same assise ; and another smaller, broader and flatter, is found in the 
 assize E. 3 e Upper Etcheminian, at the same brook. 
 
 The following are dimensions of some valves : 
 
 E. 1 e. left valve, length 4^ mm. width, 3^ mm., depth, 1 mm. Dimensions. 
 
 E. 1 e. carapace, " 4^ mm. " 3J mm., " 3J mm. 
 E. 3 e. lef c valve, " 4Jmm., " 3 mm., " 1 mm. 
 
 Xestoleberis, Sars ('65), as represented by Prof. T. Rupert Jones' species 
 S. Wrightii, from the Ordovician of Kildare, Ireland, is like this in form, 
 but is more tumid, and is not shown to possess an ocular tubercle. 
 
 Mutation phima. PI. XIII, 9 a to c. 
 
 Can. Rec. Sci., Montreal, 1902, p. 462. 
 
 A form resembling this species, but longer and larger, is found in the Mutation 
 gray shale of the volcanic rocks. The example is a complete carapace, P"™*- 
 and the valves are crushed somewhat and displaced. There appears to 
 be an ocular tubercle near the anterior end, and the fullest part of the 
 valves is in the lower half. 
 
 Sculpture. — The surface is corroded, but there are traces of a fine punc- 
 tation and of longitudinal striae on the middle part of the valve. 
 
 Size. — Length of a carapace, 5J mm. ; width, 3i mm. ; depth 2\. 
 
 Horizon and locality. — In fine gray shale in the midst of the volcanic 
 rocks of the Coldbrook group of Dugald brook, Escasonie, N.S. Scarce- 
 
 Indiana lippa, PI. XIII., figs. 10 a to d. 
 
 Can. Rec. Sci., Montreal, 1902. p. 463. 
 
 Hinge line more than half of the length of the valve. Caidinal curves Indiana lippa. 
 of moderate length ; anterior marginal curve twice as long as the poste- 
 rior, convexly arched. A very faint elevation in the position of the ocu- 
 lar tubercle : and a very shallow depression behind it. There is a thick- 
 ened and slightly elevated band all around the margin, except at the hinge. 
 
172 
 
 Sculpture. — The surface has been corroded, but there is a fine and 
 rather distant punctation showing on one example ; this becomes very 
 fine towards the hinge-line, where anastomosing ridges are developed, 
 running off toward the posterior slope of the valve. 
 
 This species differs from the type of the preceding one in its more 
 elongate form, greater plumpness and obscure ocular tubercle. 
 
 Size. — Length, 4 J mm. ; width, 2f mm. ; depth, 2 mm. 
 
 Horizon and locality. — Assise E. 3/, Upper Etcbeminian, at Dugald 
 brook, Escasonie, N.S. Infrequent. 
 
 SCHMIDTELLA. Ulrich. 
 
 The two species referred to this genus are provisionally so placed, 
 because they are tumid toward the hinge, and an ocular tubercle has not 
 with certainty been observed. The broad valve, somewhat pointed below, 
 however, is not a character of Schmidtella, and the valves are larger 
 than is usual in that genus. If the tubercle were present, the following 
 species might be included in Bradorona. 
 
 Schmidtella (?) peevetus, PI. XIII, figs. 11 a to r. 
 
 Schmidtella? pervetus n. sp. Nat. Hist. Sec. N. B. Bull. vol. iv., p. 206, pi. iV., figs. 3 a 
 to c. 
 
 Can. Rec. Sci. Moiitreal, 1902, p. 464. 
 
 Sohmidtel]a(?) " Only the right (?) valve is known [others found since.] The valve is 
 moderately arched and without furrows, and its greatest fullness is in 
 the upper half. The hinge-margin, which is more than half of the length 
 of the valve, is straight and is formed by an infolding of the edge, which 
 is without a furrow. No marginal fold was observed. 
 
 Sculpture. — The surface is covered with minute pits, closely placed ; 
 the raised spaces between the pits become so prominent on the lowerpart 
 of the valve that the surface seems tuberculated, rather than pitted ; 
 toward the lateral and the lower edges these tubercles are arranged in 
 rows, so that there the valve seems covered with obscure ridges parallel 
 to the margin. At the opposite side of the valve, towards the hinge-line, 
 the pits become very fine, and the surface of the valve has a shining ap- 
 pearance. 
 
 Size. — Length, 3 ram. ; width, 2J mm. j depth, 1 mm. 
 
 Horizon and locality. — In Assise E. 3 e. of the Upper Etchemenian, 
 Dugald brook. 
 
173 
 
 Some examples from the original bed show a valve highest in the middle, 
 and with a hinge-line half of the length of the valve. There are traces of 
 a narrow marginal fold. 
 
 " This species differs from Bradoria rugulosa in its coarser ornamenta- 
 tion and in the broader curve of the lower margin. " From S. camhrica 
 of the Protolenus Fauna it differs in the less protuberant centre of the 
 valve and the narrower and the straighter infolded border at the hinge- 
 line. The marginal fold is also more distinct in S. camSWca, Vhich does 
 not have the concentric marginal ridges of this species. 
 
 Mutation concinna, n. mut. 
 
 Can. Rec. Sci. Montreal, 1902, p. 464. 
 
 Highest part of the valve about two-fifths from the hinge ; evenly Mutation 
 sloped to the margins, except that the anterior side is somewhat more 
 turgid than the posterior. Hinge line about half of the length of the 
 valve. A very narrow fold runs around the margin. 
 
 Sculpture. — Surface with a fine but distinct punctation that develops 
 anastomosing ridges near the margins. 
 
 Size. — Length, 2J mm. ; width, 2J mm. ; depth of a valve, f mm. 
 
 Horizon and locality. — Assise E. 1 d.. Lower Etcheminian, at 
 Boundary brook, Escasonie, N.S. Scarce. 
 
 This mutation is smaller and rounder than the type. 
 
 SCHMIDTELLA (?) ACUTA, PI. XIII, figS. 12 05 tO C. 
 
 Schmidtella acuta, n. sp., Nat. Hist. Soc. N.B., Bull vol. iv. p. 206, pi. 
 
 iv., figs. 4 a to c. 
 
 Can. Rec. Sci. Montreal, p. 465. 
 
 " Valves tumid. Hinge line somewhat more than half of the length Schinidtella(?) 
 of the valve, marked by a narrow fold and furrow that extends most of ^™**- 
 its length. Valves about as wide as long, somewhat acutely pointed at 
 the lower margin. A narrow marginal fold extends along one side of 
 the valve to the pointed end. Greatest protuberance of the valve in the 
 upper half ; toward the hinge the curve of the surface of the valve is 
 turned somewhat abruptly inward toward the cardinal line." 
 
 This species has a small ocular tubercle. 
 
 "Sculpture. — The surface is smooth in appearance and somewhat shin- 
 ing, but under the lens is seen to be covered with minute pits or granula- 
 tions, uniformly distributed." 
 
 Size. — Length, 2J mm. ; width, 2J mm. ; depth, nearly 1 mm. 
 
174 
 
 Horizon and Locality. — In Assise E 3 e and J, Upper Etcheminian, 
 at Dugald brook. Frequent. 
 
 The following are measurements of the valves of this species ; 
 
 Dimensions. E. 3 e, left valve, length 2 J mm., width 2 J mm., depth \ mm. 
 
 E. 3 e, " " •' 2 mm., " If mm., " | mm. 
 E. 3 e, right " " 2J mm., " 2J mm., " | mm. 
 E. 3 i, " " " 2J mm., " 2 mm., " \ mm. 
 
 This species, by its smooth surface and pointed form, recalls the genus 
 Beyrichona of the Protolenus Fauna ; but it has not the broad flattened 
 area, near the hinge which marks that genus: on the contrary it is there 
 most prominent ; this feature belongs to the genus Schmidtella. 
 
 " From S. pervetus this species is distinguished by its finer ornamenta- 
 tion and pointed lower margin ; and from S. camhrica of the Protolenus 
 fauna by its smoother surface and narrow fold at the cardinal line. No 
 Silurian Schmidtella has the pointed valve of this species." 
 
 " HOLASAPHUS, PI X., figs. 3a to c. 
 
 Trans. Roy. Soo. Can., 2nd ser., vol. 1, p. 268. 
 Holasaphus. " Among the fossils from Young point was a trilobite apparently 
 other genera. I'elated to Asaphus, but different from any described genus. From Bathy- 
 uruH, Bill., it is excluded by the shallowness of the furrows on the head- 
 shield, and the low relief of the glabella ; it is shut out of Bathyurellus, 
 Bill., by the narrow marginal fold and long axis of the pygidium ; from 
 Protypus, Wale, by its shorter glabella, inclined to conical, and the pro- 
 longed angles of the free cheeks ; from Asaphiscus, Meek, by its Mega- 
 laspis-like pygidium ; from Asaphelina, Mun-Cham. and J. Berg., by 
 having only one spine to the pygidium ; from Platypeltis, Call., by its 
 shorter, cylindro-conical glabella, and markedly segmented and lobed pygi- 
 dium. 
 
 " Holasaphus centropyge, PI. IT., figs. 4a and h. 
 
 Holasaphus " Middle piece of the head sub-quadrate. Anterior margin with a dis- 
 
 tinct fold. Glabella sub-cylindrical, rounded in front, about one-quarter 
 longer than wide, not furrowed. Occipital ring narrow, divided from the 
 glabella by a narrow fold, and having an obscure tubercle at the back on 
 the median line. Fixed cheeks slightly wider at the middle than half of 
 the width of the glabella, widening before and behind the eyelobe, meet- 
 ing in front of the glabella, furnished with short, prominent eyelobes, no 
 ocular fillet. Posterior furrow and fold narrow, the former shallow. 
 
175 
 
 Pygidium large sub-triangular, bordered all around, furnished behind 
 with a sharp q)iBe about one-thii-d of its length. The axis is prominent 
 and has three distinct rings and three obscure ones at the back of these ; 
 each of the front rings is furnished with a small tubercle at the back edge. 
 The side lobes of the pygidium have four costse and sometimes a fifth rib 
 is obscurely shown ; the furrows of the side lobes are straight and those 
 toward the back are directed more and more backward. 
 
 Sculptttre. — This consists of a fine granulation invisible to the naked eye. 
 
 Size. — Middle piece of the head — Length 10 mm. Width at the front 
 11 mm., at the back 15 mm. Pygidium length exclusive of the spine 9 
 mm., length of spine 3 mm., width 14 mm. 
 
 Locality. — Young point near George River station. Cape Breton. 
 
 The material on which the above description is based contains only the Compared 
 parts figured, and a large free cheek, which appears to belong to another ^^^^* 
 species j it is similar to the cheek of an Angelina (PL II., fig. b.). The 
 rock in which this fossil occurs is distorted by pressure and the figures are 
 an average of several examples corrected for the distortion. 
 
 Dr. Jules Bergeron has decribed a Megalaspis from the Lower Arenig 
 beds of the south of Prance, whose pygidium is similar to that of our 
 .species, but of which the head is unknown ; his pygidium, however, is 
 more exactly that of a Megalaspis.* 
 
 Mr. Walcott has described a pygidium from the Pogonip group of 
 Eureka, Col., Bathyurvs congeneris, with a broken sp ne which is like 
 ours, but it lacks the border-fold. ^ 
 
 Bathywrus caudatux, Bill., from the G-A beds of the Quebec group in 
 northern Newfoundland, based on a pygidium only, resembles our species 
 in the number of segments in the pygidium and in possessing a terminal 
 spine, but it has no furrow within the border." * 
 
 Since the above description was written, the movable cheek of this Movable 
 species has been obtained. It is long, rather narrow behind, and ter- ™^''- 
 minates in a long slender genal spine about half of the length of the 
 cheek. There is a marginal fold which is about half as wide as the inner 
 area of the cheek at the eye-lobe ; at the front it extends into a doubleur 
 that passes beneath the front of the middle piece of the head shield. The 
 inner margin of the cheek is not well preserved in the examples known, 
 but the extension of the sutural line, both in front and behind the eye- 
 
 ' Massif Ancien au sud du Plateau Central, p. 340, PI. iv., figs. 3 and 4. 
 " Palaeontology of Eureka District. PI. viii, figs. 8 and 8a. 
 ' Palaeozoic Fossils, p. 261, fig. 245. 
 
176 
 
 lobe, appears to be convex. The genal spine is directed somewhat out- 
 ward from the regular curve of the folded margin of the cheek. 
 
 Horizon. — Calciferous sandstone bed of E. 2 (a ?) at Young point.^ 
 
 Paradoxidoid teilobite. pi. XI. Figs. 1 a — e. 
 
 Trilobite Parts of a large trilobite were obtained from the sandy shale that holds 
 
 Paradoxi^s. ^^^ ^^^^ named species, but there was not enough of the middle piece of 
 the head to determine the genus. The known parts are such as might 
 be found in a Paradoxides having long eyelobes, and as belonging to so 
 old a fauna, these fragments are of especial interest. The parts indicate 
 a species as large as P. eteminicus or P. micmac. The form of the pygi- 
 dium indicates that the thorax possessed long, backward-bent posterior 
 pleurae. 
 
 Sculpture. — The matrix is so coarse that but little of the ornamenta- 
 tion is preserved. It may be said, however, that the movable cheeks 
 were marked by sub-parallel anastomosing raised lines, about 4 or 5 in 
 the space of a millimetre. The doubleur was also ornamented with 
 parallel raised lines. 
 
 The movable cheek of an unknown trilobite, figured with the original 
 description of Holasaphus centropyge, is probably of this species. The 
 parts found are part of a glabella and of the movable cheek, two pygidia, 
 and various body segments. 
 
 Horizon and locality. — In sandy shale at Young point, George river, 
 Cape Breton, N.S. 
 
 SoLENOPLEURA Bretonensis, n. sp. PI. XI., Figs. 5 a — c. 
 
 Solenapleuro The middle piece of the head-shield is trapezoidal in outline. Anterior 
 (?) Bretonen- ■ -, n t ^ ■ , ^ 1.1,,, , 
 
 sis. marginal rold prominent ; front area 01 the cheeks long, convex, and as 
 
 wide as one-third of the length of the glabella. The glabella is ovate, 
 enclosed by deep dorsal furrows, and having a strong occipital furrow ; 
 three slightly impressed lateral furrows are formed on the glabella, of 
 which the posterior arises opposite the middle of the fixed cheek, and 
 curves backward nearly to the occipital furrow ; the middle furrow 
 appears a little behind the ocular fillet, and has a curve similar to that 
 of the posterior furrow ; the anterior furrow is opposite the ocular fillet, 
 is short and turns somewhat forward ; thus the two anterior furrows are 
 close together. The occipital ring is about as wide as the front area of 
 the cheek, is well rounded and has no spine. The fixed cheek has a dis- 
 tinct ocular fillet, and a long eyelobe ; it is tumid, but depressed con- 
 
177 
 
 siderably below the glabella ; a deep furrow at the back corresponds to 
 the occipital farrow. 
 
 A movable cheek supposed to be of -this species, found in the same 
 assise, but at a different locality, has a correspondingly long eyelobe 
 curve, and is remarkable for the wide and high marginal fold ; this is as 
 wide as' the area of the cheek at the middle ; there appears to have been 
 no genal spine, but the lower outer corner of the cheek was bluntly 
 pointed. 
 
 Detached pleurae occuring with the parts of this trilobite are like those 
 of Ellipsocephalus, bluntly rounded at the end, and have a straight furrow 
 deepening toward the end. 
 
 Sculpture. — The middle piece has a finely granulate surface; the 
 movable cheek appears to be more coarsely granulated, but this appear- 
 ance may be due to the coarseness of the matrix. 
 
 Size. — Length of the middle piece of the head-shield 12 mm., width at 
 the front 11 mm. ; at the back about 19 mm. Length of the movable 
 cheek 12 mm. ; width 5 mm. Length of a pleura 6 J mm. ; width 2 mm. 
 
 Horizon and locality. — Assise E. 3/. Upper Etcheminian Fauna. The 
 heads from Gillis, Indian brook, the movable cheek and pleura from 
 Dugald brook, Escasonie, N.S. 
 
 This species is referred to Solenopleura on account of the deep dorsal 
 furrows and occipital furrow, absence of occipital and genal spines, prom- 
 iment and rounded glabella, convex front area to the middle piece of the 
 head-shield, and strong eyelobe and fillet. 
 
 It differs from all the species of Solenopleura of the Paradoxides Beds 
 by its long eyelobe. If it were not for this it would be near S. bracky- 
 metopa Ang. var. as figured by Dr. Brogger.* 
 
 Taken alone the movable cheek referred to, this species compares best Uesembles an 
 with that of anAnomocare, a genus ,of the Upper Paradoxides Beds of -*^"°™°<=''''^- 
 Sweden. 
 
 EOEYPTEROID CeUSTACEAN ? PL XI. fig. 3. 
 
 A broken piece of the test of a crustacean was collected at GUlis Doubtful 
 Indian brook, which simulates the head-shield of a Xyphosuroid crusta- crustacean, 
 cean. If not this it is the axial ring of a trilobite, which bore paired 
 tubercles near the middle of the ring ; it is abraded at the front. 
 
 * Om Paradoxides skifrene ved Krekling. Christiania, Nyt Magazin 1878. 
 
 12— C. R. 
 
178 
 
 The test is narrowly semicircular/is moderatly arched in froAt and at 
 the sides, but had a steep slope behind where it was attached i to' the next 
 joint of the skeleton. 
 
 Nearly half way from the back on the right side there is a prominent 
 circular tubercle, and in a corresponding position on , the left side an 
 abraded space of similar form. Faiijt furrows go out^from those tuber- 
 cles, in front and behind them, toward the lateral margins of the test. 
 
 The apparent eyelobes in this test are in about the position of the eyes 
 of Limulus, but farther back than the normal position in Eurypterus. 
 Aglaspis of Hall, from the Upper Cambrian of Wisconsin, has circular 
 eyes like the tubercles in this test, but they are much closer together, 
 and nearer to the front of the shield. 
 
 Sculpture. — The surface is very finely granulate and punctate. 
 
 Size. — Length, 7 mm. ; width, 10 mm. 
 
 ^ Horiiion atid locality. — Sandy shale of Assise E. 3 /" at Gillis, Indian 
 brook, Escasonie, N.S. Rare. 
 
 Dr. J. C, Moburg has described a fossil from Sweden found in a hori- 
 zon corresponding to the Etcheminian terrane, which is not unlike this.* 
 He refers it doubtfully to the genus Kutorgina. Only casts of the organ- 
 ism have been obtained, so that the texture of the test is unknown. It 
 has round tubercles corresponding to the supposed ocular tubercles of this 
 form, but they are more anterior and closer together and so are more 
 nearly in the position where the eyes of the Silurian Eurypteroids are 
 placed. This species is represented as having a raised rim and is more 
 elevated behind than the Cape Breton form, but the articulating slope is 
 not so strongly marked. 
 
 The two Etcheminian faunas, shown together in the above descriptions, 
 may be divided as follows : 
 
 Lower Fauna. 
 
 Characteristic Acrothyra signata. 
 
 species of the a sera 
 
 two Etchemi- 
 nian faunas. A. ■ tarda. 
 
 A. orta. 
 
 Acrotreta papillata. 
 
 A. lata. 
 
 Leptobolus cf. collicia. 
 
 Upper Fauna. 
 
 Acrothyra proa via. 
 
 A. prima. 
 
 A. crassa. 
 
 Acrothele avia. 
 
 A. puteis. 
 
 A. • — aba via. 
 
 A. ■ proles. 
 
 *Oin en nyupptaokt fauna i block of Kambriak Sandsten. (Geol. foren i Stockholm, 
 Bd. 14 Haft 2, 1892. 
 
179 
 
 Lower Fauna. 
 
 Xingulella Selwyni. 
 
 L. cf. tumida. 
 
 L. longovalis. 
 
 Lingulepis Gregwa. 
 
 L. 
 L. 
 
 L. 
 
 robusta. 
 
 RobertL 
 longinervis. 
 
 Obol.us (Eoobolus) aequiputeis. 
 
 O. (E.) discus. 
 
 'O. (E.) ■ — - triparilis. 
 Billingsella retroflexa. 
 
 Eradorona perspicator. 
 
 magna. 
 
 -spectator. 
 
 acuta, 
 spinoaa. 
 
 observator. 
 
 beaepuncta. 
 Isevis. 
 
 B. - 
 B. — 
 B. — 
 B. - 
 B. — 
 B. - 
 B. - 
 B. — 
 Bradoria vigil ans-obesa. 
 
 B. (?) ornata. 
 
 Escasona rutellum-prima. 
 
 E. (?) vetus. 
 
 Indiana ovalis. 
 
 Schraidtella (?) pervetus-concinna. 
 Holasaphus centropyge. 
 Paradoxidoid trilobite. 
 
 Upper Fauna. 
 
 Leptobolus at^vus. 
 
 L. insulae. 
 
 L. tritavus. 
 
 L. collicia. 
 
 L. collis. 
 
 Lingulella tumida. 
 
 Obolus Palseobolus Bretonensis. 
 
 0. (P.)- 
 O. (P.)- 
 
 I'ins. 
 
 l^ns-longus. 
 
 Leperditia (?) rugosa. 
 Bradorona perspicator — major. 
 Bradorona spectator — %quata. 
 
 B. observator — ligata. 
 
 Bradoria scrutator. 
 
 B. vigilans. 
 
 B. rugulosa. 
 
 Escasoua rutellum. 
 Indiana ovalis. 
 
 I. lippa. 
 
 Schmidtella (?) pervetus. 
 S. (?) acuta. 
 
 Solenopleura Bretonensis. 
 Eurypteroid crustacean ? 
 
 In addition to remarks made in the text of this report on the characte- 
 ristics of the two faunas it will be seen that Lingulepis particularly charac- 
 terizes the Lower fauna and Leptobolus the Upper. 
 
 12|— c R. 
 
180 
 
 Faunas of the 
 St. John 
 terrane. 
 
 Tremadoo 
 fauna. 
 
 FAUNAS OF THE ST. JOHN TERRANE. 
 
 As the faunas found in the St. John terrane in Cape Breton were not 
 separately of very many species, they are here described collectively,, 
 with reference at the end of each species to the fauna to which they 
 belong. 
 
 While Brachiopods form the bulk of the Etcheminian fossils in Cape 
 Breton, Trilobites show in considerable abundance in some of the zones 
 of the St. John. terrane, and are of varied types. The lower zones, so 
 far as this exploration went, did not produce many fossils, although at a 
 few places some forms of the Paradoxides fauna were found, and in places 
 the middle zones yield an abundance of the Inarticulate Brachiopods. 
 
 The middle zones here, as in New Brunswick, abound ia ripple-marked 
 beds filled with worm burrows, and bear other evidences of shallow-water 
 origin. These have a fauna of Atrematous Brachiopods that is quite 
 like that of the corresponding measures in New Brunswick. 
 
 There is also similarly a return to deep water beds in the upper part 
 of the terrane, and with the dark gray shales of this portion, appear 
 faunas similar to those known from this part of the terrane in New 
 Brunswick. This part, though comparatively thin, has three Upper Cam- 
 brian faunas, so that it represents nearly as wide a period of time as 
 similar shales in New Brunswick. These three faunas are those of Pel- 
 tura, Dictyonema and Asaphellus. The latter being known in England 
 as the Tremadoc fauna. In the edition of Dana's Geology of 1875 this 
 group (the Tremadoc) is classed as Silurian (i. e. Ordovician). In the 
 later edition, 1896, it is transferred to the Cambrian. Prof. Jas. Hall 
 referred species of this fauna from the sandstones of the Mississippi valley 
 to the Potsdam (therefore Cambrian) in 1863? Mr. C. D. Walcott has 
 referred strata in the west of America and at Saratoga, N. "Y., holding this 
 fauna, to the Potsdam or Upper Cambrian. But in Europe the consensus 
 of opinion (omitting Great Britain) places this fauna in the Ordovician or 
 Lower Silurian. Lindstrom says that in Sweden not one species passes 
 from the Cambrian to the Ceratopyge Fauna (i. e. the Tremadoc) while 
 nineteen species pass from the Ordovician to the Silurian (Upper). Four 
 species, however, are recorded as passing in Wales from the Lingula 
 Flags to the Tremadoc Group.* Elsewhere it is stated that 6 out of 37 
 species of cruatacea pass from the Tremadoc to the Arenig in Wales, t 
 So that it is difficult to draw a line of absolute division between Cambrian 
 and Ordovician, either above or below the Tremadoc. 
 
 *Mem. Geol. Surv. G. B., vol. iii, p. 365, etc. 
 tibid. p. 353. 
 
181 
 
 On the whole it seems better to hold to the prevalent English opinion 
 which places the line of the division above the Tremadoc, notwithstanding 
 the conditions that prevailed in Northern Europe, and notwithstanding 
 the fact that new and important genera of crustaceans appeared in the 
 Tremadoc slates. To adopt the line drawn by the palaeontologists of 
 Scandinavia and Germany would make necessary a revision of the Cam- 
 brian geology of America, whereby large areas and extensive faunas that 
 have been classed as Cambrian would of necessity be transferred to the 
 Ordovician, or Lower Silurian. Further, it may be inferred that this 
 hiatus in the faunas will be bridged over by the discovery of connecting 
 faunas in the strata of some other region than that of Europe. The Mount 
 Stephen fauna, for instance, in British Columbia, associates genera of 
 Ffestiniog, Dolgelly and Arenig types, and generally in the Rocky Moun- 
 tain region there is a blending of Cambrian and Ordovician types. For 
 these reasons it seems undesirable to abandon the old classification which 
 drew the dividing line at the base of the Arenig, and made the appearance 
 of the Arenig graptolites the starting point of a new system. 
 
 The beds from which this fauna was taken appear in outcrops along 
 the left bank of McLeod brook, in Boisdale, Cape Breton, N.S., the best 
 locality being about an eighth of a mile below the bridge that crosses 
 that stream in McMuUin settlement. The rock is a soft, fine-grained, 
 dark gray shale, not very different in appearance from that which, on the 
 opposite side of the valley of McLeod brook, carries the Dictyonema 
 fauna. The rock easily softens when exposed to the weather, but is 
 compact and firm lower down. The classes and phyla represented here 
 are Brachiopoda, Lamellibranchiata, Gasteropoda, Yermes and Crustacea. 
 
 If one were to be governed by stratigraphical considerations alone, the 
 indications would rather place the Tremadoc fauna of McLeod brook 
 below the Dictyonema fauna than above it, as it lies to the north of 
 that fauna, and on the north side of the McLeod brook valley the lower 
 Cambrian strata are found, but the close folding of the measures and the 
 variable dips make the stratigraphy an unreliable guide for the minuter 
 groups within the divisions. We assume therefore that this fauna repre- 
 sents the highest portion of the St. John terrane present in Cape Breton. 
 
 The following species described in this report, came from the Tremadoc 
 horizon. 
 
 Urotheca. 
 Acrotreta sipo. 
 Leptobolus cf. linguloides. 
 
 Bellerophon semisculptus 
 Parabolinella quadrata. 
 P. cf. limitis, 
 
 Parabolinella quadrata. Species of this 
 
 ^ fauaa. 
 
182 
 
 Lingulella' cf. Davisii, Salt. 
 
 L. cf. lepis, Salt. 
 
 Modiolopsis of. solvensis, Hicks. 
 
 Bdllerophon iiisulse. 
 
 B. — Brfetonensis. 
 
 Triaxthrufe Belli. 
 Angelina (?). 
 
 Asaphellus Homf rayi' var. 
 A. — — planus. 
 
 TheDictyone- The Dictyonema fauna, like that of the Tremadoc group, has so far 
 been recognized only in the valley of McLeod brook, and is found in 
 similar gray and dark gray shales. The species are : — 
 
 The Peltura 
 fauna. 
 
 The Parab- 
 olina fauna. 
 
 Dictyonema flabelliformis Eichw. 
 Acrotreta biseota. 
 Schizambon priscus. 
 Leptobolus gemniulus. 
 
 Lingulella concinna. 
 
 L. cf. lepis. 
 
 Linnarssonia cf. Belti. 
 Monobolina refulgens. 
 
 The Peltura zone gives a more varied fauna, which is contained in 
 similar slates with some thin limestone bands. 
 
 Lingulella (Westonia) Escasoni. 
 Orthis lenticularis. Wahl. 
 Camarella (?). 
 AgUostus sp. 
 
 A. trisectu's-ponepunctu's. 
 
 A. — — germanus. 
 
 Parabolina Dawsoni. 
 Sphserophthalmus Fletcheri. 
 
 S. alatus. Boeck. 
 
 Ctenopyge pecten. Salt. 
 Peltura scaraboides. Wahl. 
 
 There seems to be a somewhat abrupt transition from thin flags and 
 sandstones below the Peltura horizon to the assise which contains that 
 fauna. It is marked on East bay by the occurrence of a calcareous 
 sandstone full of phosphatic lumps and nodules, and with ripple marked 
 layers. This would indicate deposition in shallow water near a shore 
 line, whereas the fossils of the underlying Peltura beds indicate rather deep 
 water and quiet seas. Unless there is a break in the succession here, such 
 as we have not observed elsewhere, these thin flags and phosphatic layers 
 should represent tho Parabolina zone. The fossils are : — 
 
 Lingullella Isevis var, grandis, and var. lens. 
 
 The band below. Assise C. 2, c. has yielded fossils in the valley of the 
 Mira river, where there are a few species of small size, viz : — 
 
 Lingulella radula, var. aspera. 
 Leptobolus flumenis. 
 
 Lingulepis rotunda. 
 
 The Upper The middle members of this division of the St. John terrane, though 
 
 r 3.1*3.00X^1 OPS 
 
 fauna. showing an abundance of fossils, present them only in small variety. 
 
183 
 
 The species are as follows- :^- 
 
 Lingulepis Starri, var. Beyrichia triceps. 
 
 L. . var. exigua. Paradoxides Forchhammeri, var. 
 
 LinguUella sp. Cteniohnites bisulcatus (track). 
 Obolus sp. , 
 
 Considering the fineness of the shales of the lower division (Acadian) The Lower 
 of the St. John terrane, it is singularly deficient in fossils. Among those f^n^°^^^^^ 
 found were : 
 
 Palseacmea sp. Ptychoparia sp. 
 
 Agnostus, sp. (longifront). Paradoxides cf. rugulosus. 
 
 DESCRIPTION OP THE SPECIES. 
 Ueotheca, sp., PI. XVIIL, fig. 6. 
 Bull. Nat. Hist. Soc. of N. B., No. iv., p. 411, pi. xviii, fig. 6. 
 
 A thin chitinous tube, seemingly of this genus, occurs sparingly. It is 
 thickened along one side and is maiked by very minute longitudinal 
 strise. 
 
 Horizon and locality. — Pine gray shale of 0. 3 c^. McLeod brook, 
 Boisdale, N.S. 
 
 ACROTEETA c/. sociALis. vonSeebach. PI. III., figs. 5 a-k. 
 
 cf. Acrotreta socialis, v.Seeb., Zeitschr. der Deutsch. geol. Gesellsohft., 
 Vol. xvii, 1865, p. 341, pi. viii, a, figs. 1-4. 
 
 cf. Acrotreta nocialis, v.Seeb., G. Linnarsson, 1898, Brachiopods of Para- 
 doxides Beds of Sweden, Bihang till K. Svenska vet. Akad-Handl. 
 Bd. 3 No. 12, p. 16, Tafl. iii, figs. 32-34. 
 
 Bull. Nat. Hist. Soc. of N. B., No. iv., p. 392, pi. xv., figs. 5 a-k. 
 
 A small species with coarse surface characters and strong muscle scars. Acrotreta 
 
 cf. socialis 
 Ventral valve moderately elevated, sub-circular in outline, somewhat described. 
 
 flattened, on the cardinal slope, where, in outline, it is slightly convex ; 
 
 nearly straight in the anterior slope. Interior — At the back there are 
 
 one or two faint grooves on the median part of the cardinal slope ; the 
 
 foraminal boss is a wedge-shaped one with the point directed forward ; 
 
 this is enclosed by two sub-parallel, deep, rounded pits, for attachment of 
 
 muscles. Behind the foramen is the back of a ridge, similar to a crescent, 
 
 that encloses the apical part of the shell behind, and laterally; in the 
 
184 
 
 Comparison 
 with other 
 pecies. 
 
 front half of the space thus enclosed is a faint outline of a visceral callus 
 of a lozenge shape. The position of the vascular trunks is probably out- 
 side of the horns of the crescent, thence extending forward ; about a third 
 or a quarter from the front of the shell is a crescentic row of short vas- 
 cular grooves. In front of this row of grooves are one or two growth 
 ridges, and the flattened border of the valve. 
 
 The dor'sal valve is orbicular in outline ; its height is less than half of 
 that of the ventral. The valve is strongly arched in the posterior half, 
 but somewhat flattened on the posterior lateral slopes. Interior. — This 
 is marked by three strong radiating ridges in the posterior half of the 
 valve ; at the origin of these ridges are a pair of pits with a small tubercle 
 in each, marking the position, of the cardinal muscles. Of the three 
 radiating ridges, the central is a narrow median ridge, with three sharp 
 keels ; for half of the length of the valve this ridge is prominent, but 
 fades away in the anterior third of the valve ; at the end of this ridge 
 would be the scars of the anterior laterals ( "j." ). The lateral ridges 
 are broader than the mesian one, but not so long ; outside of them are 
 the impres.sions of the lateral muscles. 
 
 Sculpture. — -The roughness of the matrix prevent a good presentation 
 of the surface characters of this species. Some examples of the ventral 
 valve show fine concentric ridges, of which there are about ten in half 
 the length of the anterior slope (i. e. about 10 to 1 mm.) ; the surface of 
 these ridges appears to be granular. 
 
 Size. — The largest dorsal observed was 3 mm. across, but the greater 
 number are not more than 2 mm. The full-grown ventral is about 2 mm. 
 high, and the dorsal less than one. 
 
 Horizon and locality. — In gray flags of Div. 2 c on the eastern slope of 
 the valley of McNeil brook, on the road to Trout brook. Found in 
 various attitudes in the sandy bed. The ventrals are both upright, 
 inclined, and lying on their sides in the layers. From this locality Mr. 
 Fletcher has reported Obolella, a genus in which, at the time his report 
 was written, many of these small brachiopods of the Canadian Cambrian 
 were included. 
 
 Linnarsson described very fully a species like this from the Paradoxides 
 beds of Sweden.* He found it to range through the whole of the Para- 
 doxides zone. Our form belongs somewhat higher up. 
 
 From A. Baileyi of the (lower) Paradoxides beds in New Brunswickt 
 this species is distinguished by its smaller size, and as to its interior by 
 
 * Loc. cit. 
 
 t Trans. Roy. Soc. Can., Vol. iii, sec. iv, 
 
 p. 36, pi. V, figs. 13, 13a, 6 and c. 
 
185 
 
 its narrow umbonal ridge to the ventral valve, higher cardinal area, and 
 by the longitudinal pits that enclose the umbonal ridge. It differs from 
 A. ^mraula of the Protolenus faunaj (see PI. III., figs 4 a-d) in the sharp 
 umbonal ridge of the interior of the ventral, and by the strong lateral 
 ridges of the inside of the dorsal valve. From Acrothyra proavia of the 
 Etcheminian fauna§ (see PI. II., figs. 2 <i-g) it is distinguished by the 
 more central apex of the ventral valve, and by the prominent ridges of the 
 interior of the dorsal valve, as well as by its larger size. From A. gemma, 
 Bill. (Walcott)ll it is distinct by its smaller size, less proportionate height 
 of the ventral valve, its narrow umbonal boss and its more obscure 
 cardinal area, also by a difference in the internal markings of the dorsal 
 valve. I 
 
 AcEOTEETA sipo, PI. XVIII. figs. 1 and 2. 
 
 BilU. Nat. Hist. Soc. of N.B., No. iv. p. 406, pi. xviii figs. 1 and 2. a . . • 
 
 ° Aorotreta sipo 
 
 A small species with somewhat overhanging umbo. described. 
 
 Ventral valves nearly as high as long. Umbo projecting behind the 
 cardinal line, somewhat bluntly pointed, (some valves are trumpet shaped 
 toward the margin) and a little broader than long. Interior. The fora- 
 men passes outward through a short siphon which is attached to the dor- 
 sal side of the valve ; on each side of it are traces of lateral septa ; in 
 front of it is the faint impression of a callus which extends one-third of 
 the distance to the anterior margin. 
 
 The dorsal valve is transversely oval, and arched from hinge to front, 
 more strongly toward the hinge ; the lateral edges are flattened, especially 
 toward the hinge. Interior. — This shows traces of scars of lateral (?) 
 muscles on each side of the umbo, and of a pair of central muscles near 
 the middle of the valve. A distinct, though low, median septum crosses 
 the valve nearly to the front margin. 
 
 Sculpture. — No concentric striae were observed on this species, but the 
 surface of the valves is minutely granulated. 
 
 Size. — The largest ventral observed had a size at the orifice of 3 x 3 
 mm., and others a height of 2 J mm. A dorsal was 2f x 3 J mm. ; height 
 :| of a mm. 
 
 The siphon is seldom preserved. 
 
 Three quarters of the ventral valves collected stand vertically in the 
 mud in which they were entombed. 
 
 % Trans. New. York Acad. Sei. xiv, p. 126, pi. v, figs. 5 a-d. 
 § Bull. Nat. Hist. Soo. N.B., vol. iv, p. 203, pi. iii, figs. 2 a-f. 
 IT Bull. "U.S. Geol. Surv. 30, p. 98, pi. viii, figs. 1, la-6. 
 
186 
 
 Compared 
 with other 
 species. 
 
 Acrotreta 
 
 bisecta 
 
 described. 
 
 Horizon and locality^ — Gray shales- of. the assise C 3-c^, at McLeod 
 brook, Boisdale, NiS. 
 
 This little shell seems to throw light on the function of the callraf in' 
 Aorothyra and Acrotreta. In ordinary species of Acrotreta the strong^ 
 thickened ring around' the foramen, within the shell, only needs to be 
 raised still further to produce a siphon. And the siphon in this species, 
 attached as it is to the dorsal side, holds the position of' the callus in 
 Acrothyra. 
 
 This must be near in age to Acrotrtta gemma of Billings, than which 
 it is a little larger, but as we do not know anything of the interior of" 
 Billings species (which belongs to the Arenig horizon) we do not use his- 
 name. 
 
 ACEOTEETA BISECTA, PL XI. figS. 5a-gr. 
 
 Bull. Nat. Hist. See. of N. B., No. iv. p. 275, pi. xvi. figs. 2a-gt 
 Shell substance thin, calcareo-corneous. Outline of the valves, oblately 
 circular. 
 
 Ventral valve elevated conical. Height about one-quarter less than the 
 width. The umbo is about a quarter of the length of the valve fi-om the 
 posterior margin. The valve is somewhat flattened on the posterior slope 
 at the cardinal area, which is nearly as long as half the width of the valve, 
 and has a deltidial area, bounded by distinct furrows ; elsewhere the valve 
 slopes regularly to the margin. Interior. — The mould is always truncated' 
 and has a somewhat convex summit ; in some examples there are traces 
 of one or two diaphragms extending across or intq this part of the valve, 
 from the anterior slope. A crescent-like ridge extends around the back 
 of the summit of the mould and dbwn the lateral slopes. Towards the 
 front of the valve a pair of low ridges radiate toward the front of the- 
 mould, but fade out at one-quarter from the anterior margin. 
 
 The dorsal valve is most convex at the back, where the slope is nearly 
 vertical ; it has a long flattened slope to the front. Interior. — The mould 
 of this species is marked by a long, deep, narrow furrow (indicating a 
 strong mesian: ridge) ; this is somewhat broader in the anterior third than 
 elsewhere ; the; mould also has two pairs of pits near this furrow, which 
 perhaps indicate the position of the central muscles ; the posterior adduc- 
 tors are indicated by bosses on the mould near the cardinal line, and the 
 lateral muscles by depressions near the ends of the cardinal area. Fine 
 ra'diating vascular lines are visible in the front half of the valve on each 
 side of the median ridge. In young valves this ridge is only two-thirds 
 of the length of that in the adult valve, the anterior third being smooth. 
 
 * New York State Geologist's Report, 1891, Hall & Clarke, pi. i,. fig. 7. 
 
187 
 
 Sculpture. — The surface is marked by minute concentric beaded i idges, 
 visible only with a strong lens ; there are stronger growth lines at 
 intervals. 
 
 Size. — Length, 3 mm. Width 3J mm. Height of the ventral valve, 
 one-fifth to one-quarter less. 
 
 Horizon and locality. — The fine dark gray shales of the Dictyonema 
 beds (C. 3c.) at McLeod brook, Cape Breton. 
 
 On reexamining the specimens from this horizon at Navy island, St. Compared 
 John, N.B., which I had compared with A. Baileyi, of the Paradoxides ^^^^* ^ 
 beds, I find they are of a species identical with that from McLeod brook. 
 It is distinguished from A. Baileyi by the long, sharp median ridge of the 
 interior of the dorsal valve ; the convex summit of the mould of the ven- 
 tral valve also distinguishes it from that species, in which the summit 
 is concave, and porportionately smaller. 
 
 From A. socialis. Von Seebach,* this species is distinguished by its 
 somewhat larger size, and by the absence of the sharp wedge-shaped 
 furrow in the top of the mould of the ventral valve ; by the absenpe of 
 the strong lateral furrows in the mould of the dorsal valve of that 
 species ; also by the deeper and longer mesian furrow of the dorsal valve 
 of the McLeod brook species. 
 
 From A. gemma, Walcott,t this species is distinct by the convex top-of 
 the mould of the ventral valve, by the absence of an area to the dorsal 
 valve, and the enlarged posterior end of the median ridge in this valve. 
 
 From A. gem,mulaX this species is distinct by the larger size, convex 
 summit of the ventral mould ; and by the smaller scars of the posterior 
 adductois and sharper and longer median ridge of the dorsal valve. 
 
 ScHizAMBON Priscus, Plate xi., figs. Qa-d. 
 
 BuU. Nat. Hist. Soc. of N. B., vol. iv, p. 277, pi. .., figs, iatod. 
 Shell substance firm, corneous (or calcareo-corneous ? ). Outline orbi- 
 cular, and valves lenticular and of moderate depth. Schizambon 
 
 priscus 
 Ventral valve with a rounded umbo, the greatest depth in front of the described. 
 
 umbo, about two-thirds from the front. About one sixth or one eighth 
 from the posterial margin, the valve is perforated by an oval foramen, in 
 
 *Brachiopoaa of the Paradoxides beds of Sweden. G. Linnarsson, Stockholm, 
 1876, p. 16, pi. iii, figs. 32-35. 
 
 tU. S. Geol. Surv. Bull. No. 30, p. 98, pi. viij, figs. la-6. 
 JBoy. Soc. Can. Trans., vol. xi, sec. iv, p. 87, pi. xvi, fig, 2a-d. 
 
188 
 
 Compared 
 with other 
 species. 
 
 front of which two narrow diverging ridges run forward to the front of 
 the valve, where they are about as far apart as one-quarter of the length of 
 the valve. There is considerable variation in the size and position of the 
 foramen in the example collected. Interior. — The foraminal passage is 
 smaller within than at the outer surface of the shell, and is surrounded 
 by a raised rim ; from it two thread-like grooves run forward into the 
 front of the umbonal cavity. (The ridges that run forward from the 
 foramen on the outer surface of the shell are preserved as grooves on its 
 inner surface.) The visceral callus, of a lenticular outline, extends about 
 half as far in front of the foramen as that is from the posterior margin ; 
 it is crossed by two faint diverging ridges on each side, and is bordered 
 by two stronger lateral ridges, widely diverging, that mark the position 
 of the lateral muscles ; the length of these ridges is about one-third of 
 that of the shell. Faint traces of vascular trunks are found in the lateral 
 and posterior part of the shell and make a regular arch about one-sixth 
 of the length of the shell, from its margin. The margin is flattened, 
 especially in the posterior half, toward the umbo. 
 
 The dorsal valve is flatter than the ventral, and its umbo somewhat 
 removed from the posterior margin. The central part of the valve has 
 a flattened triangular space extending back towards the umbo ; as the 
 lateral margins are flattened in the posterior half, a low flattened ridge 
 extends out on each side from the umbo to the mid-length of the valve. 
 Interior. — This shows a broad flattened mesian ridge extending half way 
 across the valve from the posterior margin, on each side of this, about 
 one-third from the back of the valve, and nearly as far apart, are 
 obscure oval marks, probably indicating the position of the anterior 
 adductor muscles. The margins of the valve are flattened behind. 
 Sculpture. — This consists of sharply defined but very minute concentric 
 and radiating ridges that form a delicate cancellated pattern ; on the 
 highest part of the shell the concentric ridges are most distinct, on the 
 front part, the radiating ridges. No cicatrix marking the advance of the 
 foramen was observed, but a progressive change of this kind is pro- 
 bably indicated by the paired thread-like ridges behind the foramen on 
 the interior of the ventral valve. 
 
 Size. — Length and width each 4 mm. Depth about § of a millimeter 
 that of the dorsal valve less. 
 
 Horizon and locality. — Fine dark gray shales of the Dictyonema beds 
 (C. 3c) at McLeod brook. Cape Breton. 
 
 This pretty little species is the smallest and oldest known of its "enus. 
 Mr. Walcott indicates for S. typicalis a calcareo-corneous shell * but 
 
 *U. S. Geol. Surv. Monogr. viii, p. 70, pi. 1, figs. 3, Sa to c. 
 
189 
 
 while there may be aa outer calcareous layer to S. prisons, it has not been 
 detected. From the former species, which is Ordovician, it differs not 
 only in its small size, but its orbicular form ; it differs also in having 
 radiating as well as concentric striae on the outer surface. It is much 
 smaller than Dr. Ami's S. Canadensis of the Utica shale. 
 
 In one example of the ventral in this species the foramen is in the 
 umbo, but in the others it is in front of it. The ring around the inside 
 of the foraminal opening is never prolonged into a tube as in Siphonotreta. 
 
 In re-examining the material from this horizon at Navy island, St. 
 John, I find that this species is present there also, but the surface mark- 
 ing are not well preserved ; however, the form and size of the shell, and 
 the foraminal opening, show it to be the same species. 
 
 LEPT0B0LU8 FLUMENIS, n. Sp. PI. 'XI. figS. a — f 
 
 A narrowly ovate species, somewhat straight on the sides, and broadly Leptobolua 
 rounded in front. Srib^. 
 
 The ventral valve has an obtusely pointed beak, bent down at the apex. 
 Sides of the valve somewhat sharply sloped in the posterior half and 
 gently sloped in front. Interior. This shows an area nearly half a milli- 
 metre long, and a visceral callus extending about half the length of the 
 valve. The lateral ridgeb within the valve extend as far ; and in front of 
 them, reaching to within a sixth of the length of the valve from the front, 
 are a pair of arched vascular groves, not far from the margin of the valve ; 
 numerous external branches from these trunk grooves extend to the flat- 
 tened margin of the valve ; the individual length of these branches is 
 about equal to the width of the main groove. 
 
 The dorsal valve is obtusely rounded at the hinge area, which is very 
 short, and here and at the sides the valve is strongly arched downward, 
 but is gently sloped down in front. Interior. — In front of the linear 
 cardinal area is a pair of pits marking the insertion of the cardinal muscles. 
 The middle of the valve for more than half the valve's length has a flat- 
 tened band marking the progress of the central muscles during the 
 growth of the shell. At the front this band is about one sixth or one 
 eight of the width of the valve, and at its sides are faint prints of the 
 central muscles ; and at the front are two pairs of minute pits, one or both 
 of which marks^the position of the anterior laterals. The place of the pos- 
 terior laterals is marked by a series of small pits near the margins in the 
 posterior third of the valve. In front of these pits are the strong arched 
 grooves left by the vascular trunks, which extend across the middle half of 
 the valve near its margins. 
 
190 
 
 Sculpture. — No examples have been obtained showing the surface mark- 
 ings, except those near the front of the valve ; but both valves show from 
 four to six ridges of growth in the anterior quarter of the valve ; these ridges 
 are broadly curved in the middle part, but more abruptly at the sides. 
 
 Size. — Ventral valve 4 mm. long and 2\ mm. wide. The dorsal valve is 
 nearly one half millimetre shorter than the ventral. 
 
 ■Compared Horizon and locality. — In grey flags of the Middle Cambrian (Div. 
 
 ' 2 c.) on the eastern slope of the valley of McNeil brook (on road to 
 Trout brook) Mira river, N.S. 
 
 This species is of nearly the same size as L. insulce, but is less elliptical 
 in outline, and the valves are more flattened in front ; the area of the ven- 
 tral valve also is longer, and that of the dorsal shorter than in that species ; 
 also the central group of muscles is not set so far forward as in that of 
 the dorsal of the species cited. 
 
 This species differs from L. atavus of the Etcheminian terrane in having 
 the central muscles of both valves set farther back. 
 
 Leptobolus gemmulus, pi. XIV., figs, la to c. 
 Oh Mia ? gemmula, Trans. Roy. Soc, Can., vol. ix, sec. iv, p. 41, pi. 
 xii, figs. 8a-c. 
 
 lientobol The foUowiiag is the original description of this species : — 
 
 described Ovate acuminate, sides somewhat straight in the posterior half, 
 
 rather broadly rounded in the anterior half of the shell. Test, calcareo- 
 corneous. 
 
 Ventral valvo acuminate behind ; it has a small triangular area, with 
 pedicle groove and low beak. The interior of the valve has a ridge, most 
 distinct in the posterior third, along the median line ; this part of the 
 ridge appears double in some shells, but in others there is only a single 
 sharp ridge. On each side of this part of the ridges, but not extending 
 its full length, are suboval scars of the adductor muscles. The central 
 part of the shell is occupied by a large bilobed sub-circular scar (?, rather 
 depression). The outer borders of these two depressions of the shell are 
 defined by a sharp line, elevated in the middle of its length, and there 
 bent toward the centre of the shell. The margin of the valve appears 
 flattened and crenulated. 
 
 The dorsal valve is blunt and depressed at the umbo. Interior smooth 
 except at the posterior end, where concealed in the blunt beak, is a short 
 ridge, dividing the small scars of the ^posterior) adductor muscles; a 
 small scar on each side of the valve close to the edge, and abqut one 
 
191 
 
 third from the beak, marks the attachment of the adjuster muscle. 
 Opposite this there is a slight elevation or ridge on the median line. 
 
 Sculpture. This consists of concentric ridges and lines, and of less 
 conspicuous radiating ridges. 
 
 Size. Length of ventral 4J mm. ; width 3J mm. The dorsal valve is 
 one half of a millimetre shorter than the ventral valve. 
 
 Horizon and locality. In a bed of fine gray shale, in the JDictyonema 
 beds, Div. 3 c. Navy island, St. John harbor, N.B. 
 
 Although in some respect resembling a Lingulella, there are in others Resembles i 
 such wide differences in this little shell that we have sought for relations Lmgulella. 
 in other genera, and notably to OlJolella ". 
 
 But as Obolella is now limited to thick calcareous shells, this species 
 cannot find a place there, and our later studies have induced us to look 
 to Hall's genus Leptobolus as the nearest approach to shells of this 
 type. 
 
 The specimens from McLean brook, Cape Breton, are in better preserva- 
 tion than those of Navy island and show more clearly the characteristics 
 of the species, the description of which is here reported. 
 
 Ventral valve. Interior. The cardinal area is from one sixth to one 
 quarter of the length of the valve. " The suboval scars " in the posterior 
 part of the shell are not now thought to be due to the adductor muscles 
 which are smaller and further forward. There is a narrow median 
 septum on some Cape Breton examples, extending from the umbo one 
 third of the length of the valve. There are also lateral ridges diverging 
 from the umbo ; and, extending in an arch from the anterior end of those 
 ridges, nearly parallel to the sides of the valve, are faint impressions of 
 vascular trunks. The " large bilobed sub-circular scar " is the area within 
 these trunks. 
 
 Dorsal valve. Interior. — There are faint impressions on the median 
 line in the anterior part of ihe valve that mark the position of the 
 anterior adductor muscles ; those impressions are about one-third from the 
 front of the valve. Extending back from this to the umbo is a sharp faintly 
 'defined mesian ridge. Lateral grooves or ridges extend out on each 
 side from the umbo nearly as far forward as the mesian ridge. 
 
 Sculpture. — The better examples from Cape Breton show that this 
 species had fine, well-marked concentric ridges ; the radiating ridges 
 •belong to the surface of an innfir layer of the shell. 
 
 At the time this species was described, its aflSnities were obscure, be- 
 cause in such small shells, the details are not readily observed unless the 
 
192 
 
 mud in which they were preserved was very fine and had escaped altera- 
 Reasons for tion. This was not altogether the case at Navy island in St. John basin, 
 Leptobolus '° ^^^ ^^^ medium of preservation at McLeod brook is in a more satisfac- 
 tory condition, and hence we were able to see more readily points of 
 resemblance to the genus Leptobolus. 
 
 In Obolella the shell substance is calcareous and thick ; in this there- 
 is a chitineous film, and the shell is quite thin. No very satisfactory 
 impressions of vascular trunks were observed, but the position of the 
 muscle scars and of the median ridge in both valves are most in accord 
 with Leptobolus. 
 
 Prom Lingulella this species is distinct by the uniform thickness 
 and tenuous substance of the valves. In Lingulella there is a 
 thickening of the shell in the visceral cavity, while around the brachial 
 cavity it is usually much thinner ; in Leptobolus the shell-substance is 
 thin and comparatively uniform except at the cardinal area of the- 
 ventral valve. 
 
 In the paragraph of the original description of this species, " In the 
 general form," &c., the features described resemble the characters of 
 Leptobolus as much as Obolella. or more so. 
 
 Size. — Length of ventral i^ mm.; width 3 J mm. The dorsal valve is 
 one-half millimetre shorter. 
 
 Horizon and locality. — Fine dark gray shale of Div. 3 c. at McLeod 
 brook. Cape Breton, N.S. 
 
 By comparing the figures of the Navy island form with these, it may 
 be gathered that the posterior cavity (scar) or depression of the ventral 
 valve occupies the space of the visceral cavity, while the anterior depres- 
 sion is outlined by the vascular trunks. The ridge between these two de- 
 pressions in the Navy island form might be compared to the cross-ridge 
 in the shell of Leptobolus which Prof. Hall seemed to regard as of 
 generic value. 
 
 Leptobolus, cf. linguloides. 
 
 Leptobolus cf. A small linguloid shell is not rare in the fine shale of McLeod brook. 
 
 inguoi es. ^g jj^ others of this genus, the umbo of the ventral is weak and short, 
 and so the two valves are not easily distinguishable. Owing to the thin- 
 ness of the valves the internal features are only faintly indicated. The 
 ventral shows two lateral ridges diverging from the umbo, and a callus is 
 obscurely indicated ; one example shows a trace of a vascular trunk on 
 one side. The dorsal has an obscure medium septum extending to the 
 middle of the valve. 
 
193 
 
 Sculpture. — A very fine concentric striation is visible on some valves. 
 
 Size. — Usual length, 3 mm. ; (largest, 3^ mm.); width 2J mm. ; 
 (largest, 2f mm.) 
 
 Horizon and locality. — Gray shale of Assise C, 3 «., at MoLeod brook, 
 Boisdale, N.S. 
 
 This species is nearly as large as LinguleUa linguloides of the Lower 
 Paradoxides beds near St. John, a species which we would also refer to 
 Leptobolus. The outline also is similar, but the umbo of the ventral is 
 weaker ; this and the smaller size may be due to a more pelagic habitat. 
 
 LiNGULEPis Stabei, var. PI. XIV., figs. 2 a-c. 
 
 LinguleUa gregwa Walcott [non mihi] Proceed. U. S. Nat. Mus. Variety of 
 Cambrian Brachiopoda, vol. xxiii, pages 669-695, [description without starri— Mr. 
 
 n 1 Walcott 
 
 The following is Mr. Walcott's description of this form under the name gregwa. ' 
 of Lingulepis gregwa. The diagnosis is arranged as nearly as possible, 
 according to the plan followed in this report. 
 
 " General form elongate ovate, with the ventral valve acuminate and 
 dorsal valve ovate triangular in outline. The outlines of the valves vary 
 as shown by a series of specimens. The convexity of the valves varies 
 with the conditions of preservation. Those from the sandstone are rather 
 strongly convex, while in the shale they are very much compressed. On 
 the dorsal valve of most young shells there is a marked and a rather broad 
 shallow sinus, extending from the umbo to the front, where it flattens 
 out. 
 
 Interior. — The plane of the cardinal area of the ventral valve is nearly 
 coincident near its edges with the edge of the shell. The area is long 
 and extends well forward on the cardinal slope. It is divided midway 
 by a narrow, rounded, deep pedicle furrow, and about halfway between 
 the pedicle furrow and the lateral margins, by an unusually well defined 
 flexure line, which is in lioe with the main vascular furrows of the interior 
 of the valves ; fine striae of growth cross the area, and arch around the 
 pedicle furrow, parallel to the base of the area. There is practically no 
 undercut beneath the area, except near the flexure line at the front mar- 
 gin of the area. The area of the dorsal valve is short and narrow, and 
 crossed by fine lines of growth parallel to its base. 
 
 The cast of the visceral cavity in the ventral valve, shows it to have 
 been relatively small, and usually confined to the posterior half of the 
 shell. There is no trace of a median septum in the ventral valve ; in the 
 13— c. E. 
 
194 
 
 dorsal valve a slightly elevated median line occurs at the bottom of the 
 groove, between the central muscle scars, that extend forward to the 
 anterior margin of the visceral cavity, beyond the anterior lateral muscle 
 scars. The visceral cavity of the ventral valve extend forward to about 
 the centre ; in some shells it is back of the centre, and in others a little 
 in front. It varies in width and outline very much as the shells vary, 
 being wide in broad shells, and narrow in elongated forms. 
 
 Description of Vascular system. — The markings left on the shell by the vascular system 
 are vtry strong, and beautifully preserved in some portions. In some 
 shells there is a double groove with a slight ridge between ; in others the 
 ridge is large, only a trace of an outer groove remaining ; in some young 
 shells, the groove is broad and shallow ; in all shells the large size of the 
 main vessels is shown by the broad, strong grooves or ridges left on the 
 shell. It frequently happens that the deeply indented lines of pits on the 
 lines of growth deeply indent the grooves and rounded ridges, left by the 
 main vessels, and mark them off into sections. The interior and lateral 
 vessels left narrow but strong grooves or ridges on the shell, which how- 
 ever are usually obscured by the strong pitting of the surfaces. 
 
 The parietal scar surrounds the visceral cavity in each valve, crosses 
 the course of the main vascular vessels, and comes back around the spaces 
 occupied by the muscle scars, terminating at the edge of the area at the 
 flexures in the ventral valve ; termination unknown in the dorsal valve. 
 
 Some of the muscle scars are finely shown in the dorsal valve and fairly 
 well in the ventral. The umbonal scar of the ventral valve is divided, 
 the pedicle scar being situated between the two parts. In the dorsal " 
 valve the umbonal scar is close to the area, and extends nearly as far 
 each side of the median line as the length of the area. 
 
 The scars of the central muscles in the ventral valve are crowded in 
 with the middle and outside laterals within the trapezoidal space. In 
 the dorsal valve, they are located on a low ridge each side of the central 
 longitudinal depression ; they are elongate oval in outline, their major 
 axis being sub-parellel to the median line of the shell ; fine longitudinal 
 lines cross the scars in the best preserved specimens ; the ridge on which 
 the central scars occur varies in strength, but it appears to be present in 
 all adult shells ; it narrows gradually posteriorly and rather rapidly to 
 the inner side of the anterior lateral muscles scars. The anterior laterals 
 of the ventral valves, are placed well back on the narrow space between 
 the edge of the area and the main vascular sinus ; they are elongate and 
 rather large ; in the dorsal valve they are elongate, with the major axis 
 inclined forward toward the median line. The middle and outer laterals 
 are situated in the trapezoidal area of the ventral valve, but neither is 
 
195 
 
 clearly separable from the other, or from the central scars, ^n the dorsal 
 valve the position of the middle and outside laterals is shown, but not 
 their form or size. The transmedian scars in the ventral valve are seen 
 just back of the anterior laterals, but they have not been observed in the 
 dorsal valve, owing to the imperfection of the shell. 
 
 Sculpture. — The surface of the shell is marked by concentric striae, and Sculpture, 
 undulations of growth, over which there is a series of very fine elevated, 
 sharply undulating inosculating lines that form a minute, irregular net- 
 work over the surface, very much like that of 0. (Lingulella) ella. Where 
 the lines are strongly elevated the effect is that of a minutely granulose 
 surface. When the thin outer layer of the shell is exfoliated the surface 
 of the various inner layers is minutely granulose in addition to the 
 flattened, radiating striae and concentric lines of growth. Interior. The 
 interior surface of both valves is often marked by concentric lines of 
 strong pits or punctse, very much as in 0. Lingulella davisi. In some 
 specimens the lines of punctse extend over the surface of the visceral 
 cavity so as to obscure the vascular markings and muscle scars. In some 
 examples only a few scattered punctse occur, while in others they are 
 present over nearly the entire surface. The small shells are thin, but the 
 larger ones are built up of a very thin outer layer and several inner layers 
 or lamella that are more or less oblique to the outer surface, especially 
 over the anterior and lateral portions of the shell. 
 
 Size. — One of the largest ventral valves has a length of 21 mm., with 
 a width of 18 mm. A dorsal valve 16 mm. in width has the same length ; 
 other example, are a litte wider than long. 
 
 Formation and locality. — Middle Cambrian. Upper Paradoxides beds. 
 Siliceous shale and thin bedded sandstones west side of McLean brook, 
 above Marion bridge, Salmon river. Gillis hill, 13 miles south of 
 Marion bridge, Cape Breton island, Nova Scotia. [The locality on Mc- 
 Lean brook in on the horizon C. 2 b. G. F. M.] 
 
 Observations. — This appears to be a representitive of 0. (L.) acumi- Comparison 
 natus which is so abundant in the Middle Cambrian of the Upper Missis- ^*i^ "^ 
 iippi valley, and the passage beds between the Cambrian and Ordovician 
 adjoining the Adirondack mountains of New York. It differs from that 
 species in its greater average width and in its surface characters." 
 
 The above being the description of a shell from McLean brook, Mira 
 river it is clearly not L. Gregwa which occurs at another locality and in 
 lower terrane. A thousand feet in vertical thickness of sandstones, shales 
 and fags separate the the two species and three distinct Cambrian faun- 
 as intervene. The " species " is really a variety of Lingulepis Starri of the 
 13^—0. E. 
 
196 
 
 Johannian division of the St. John terrane. But as Mr. Walcott has 
 obtained some excellent material of this species, showing it far better than 
 the original material from St. John, I have adopted the above as a good 
 description of the species. Some differences however may be noted. 
 
 I have found the visceral cavity of the ventral valve extended well into 
 the anterior half of the shell, and that of the dorsal two thirds of the 
 iength of that valve. 
 
 The foundation of the ornamentation in this shell is a rough scabrous 
 or granulated surface (with a tendency to develop anastomosing ridges 
 as in Acrothele) ; toward the beak it seldom has other character, but at 
 the middle and towards the front this surface is thrown into concentric 
 ridges, not all regularly placed, but becoming more regular toward the 
 front. Over the middle third these ridges are crossed by radial ing ridges 
 of nearly equal strength. On the middle of the valve there are about 7 
 to 9 of the concentric ridges in the space of 2 mm. In this they differ 
 from the examples of the species from the St. John locality in which 
 these ridges are much closer, and they are also more regular. 
 
 The arrangement of the muscle scars and form of the callus in this 
 species is that of Lingulepis rather than of Lingulella. The great 
 inequality of the length of the valves separates it widely from Obolus, in 
 in which the cardinal area of the dorsal valve is high, and nearly equal 
 to that of the ventral. 
 
 The back of the dorsal valve in this species seems to be subject to 
 resorption ; or else no growth takes place there, as the ends of the growth 
 lines at the hinge are far separated from each other. 
 
 The following are dimensions of a few valves of this species. 
 
 Dimensions of Valves or Lingulspis Stakbi from Band C. 2. 6. 
 
 Ventbal. 
 
 Dorsal. 
 
 No. 
 
 Length. 
 
 Width. 
 
 Depth. 
 
 No. 
 
 Length. 
 
 Width. 
 
 Depth. 
 
 1 
 Dimensions of ^ 
 the valves of ° 
 L. Starri, var. ; 
 
 5 
 
 19 
 16 
 15 
 
 17 
 13 
 13 
 13 
 13 
 
 2 
 IS 
 2| 
 2 
 
 li 
 
 1 
 2 
 3 
 4 
 5 
 
 13 
 
 12 
 
 11 
 
 15 
 13 
 14 
 13 
 12 
 
 2 
 
 
 81 
 
 69 
 
 10 
 
 
 60 
 
 67 
 
 10 
 
 Average . . . 
 
 16-2 
 
 13-8 
 
 20 
 
 120 
 
 13-4 
 
 2 
 
 Proportion . 
 
 1-2 length to width. 
 
 0-9 length to width. 
 
197 
 
 The ventral is about a fifth longer than wide, judging by these examples, 
 and the dorsal a tenth wider than long. 
 
 This form was observed to have a raised median band on the inside of 
 the dorsal valve which extended in one example four-fifths of the length 
 of the valve. The median band in several examples was traversed by 
 a narrow median groove, made double by a thread-like ridge in the middle ; 
 this groove was interrupted for a short space about one-quarter of the 
 length of the valve from the hinge. Opposite this interruption, on each 
 side of the thickened band or callus, are thinner oval areas of the valve 
 which may be ovarian cavities. 
 
 Mut. ExiGUA, N. mut. PL XIV., figs. 3 or-d. 
 
 Mutation 
 This form is smaller than that last described and shows much varia- exigua from 
 , .,. lower horizon 
 
 OUitj. described. 
 
 It is about one-third longer than wide ; as preserved in the rock, is 
 rather flat, and the shell substance is comparatively thin. 
 
 The ventral valve is ovate-acuminate, with sides straight for more than 
 half of its length, then slowly and afterwards more rapidly rounded to 
 the front. The usual proportion of length to width is 4 to 3, but others 
 are more acuminate. Yery often the umbo is mutilate, and sometimes 
 the sides of the ventral toward the hinge-line are concave in outline. 
 This valve is flattened toward the front, but more convex toward the 
 beak. — Interior. — A decorticated example shows a callus extending to the 
 anterior third of the valve, and the points of the lateral vascular ridges 
 are still farther advanced ; the vascular trunks just inside these ridges, 
 curve inward toward the front of the valve. 
 
 The dorsal valve is ovate-cuneate and as long or longer than 
 wide. It is arched down all round, and there is a depressed band along 
 the middle, over the median septum. The interior shows a strong, broad 
 median ridge or callus extending nearly to the front of the valve ; the 
 callus has a longitudinal groove. The lateral septa or vascular ridges are 
 fainter, and between these and the median ridge, just at the cardinal line, 
 are pits of the cardinal muscle. 
 
 Sculpture. — This consists of a rough, granulated surface, diversified with 
 ridges concentric to the umbo ; sometimes these ridges are distinctly vi- 
 sible from the umbo out ; on other valves they are seen only from the 
 middle of the valve forward, and are particularly plain and close together 
 near the anterior margin. On the dorsal valve toward the umbo the ends 
 
198 
 
 of these ridges are widely separated (owing to the resorption of the 
 umbo ?) and so appear more transverse there, than farther toward the front 
 of the valve. 
 
 Size. — Ventral valve ; length, 12 J mm. width, 9 J mm. depth, ^ mm. 
 
 Horizon and locaiity. — Slaty seams of the calciferous gray flags of 
 Band C. 2 a. (also in Assise C. 2 b.) at McLean brook, Mira river, Cape 
 Breton, N.S. 
 
 The folowing are dimensions of valves of this form. 
 
 Valves of LiNonLEPis Stabei, mdt. bxigua from Band 0. 2 a. 
 
 Vbntbals. 
 
 DOBSALS. 
 
 No. 
 
 Length. 
 
 Width. 
 
 Depth. 
 
 No. 
 
 Length. 
 
 Width. 
 
 Depth. 
 
 1 
 
 Dimension of 2 
 
 valves. 3 
 
 4 
 
 5 
 
 if* 
 • 11 
 
 10 
 
 3 
 
 7 
 
 n 
 
 6i 
 
 - i 
 
 1 
 
 2 
 3 
 
 4 
 5 
 
 9 
 
 5 
 
 8 
 
 7^ 
 f 
 
 1 
 
 
 54 
 
 38 
 
 24 
 
 
 36J 
 
 35 
 
 2i 
 
 Average . . . 
 
 10.8 
 
 7.6 
 
 .5 
 
 
 7.3 
 
 7. 
 
 .5 
 
 Proportion . 
 
 1.4 length to width. 
 
 
 1.04 length to width. 
 
 Compared 
 with other 
 species. 
 
 The ventral is about two fifths longer than wide, and the length and 
 width of the dorsal valve are about equal. 
 
 The acuminate beak of the ventral is usually broken off j otherwise 
 the disparity in the length of the valves would be greater. 
 
 This form differs from Lingulepis acuminata of the Potsdam sand- 
 stone of the St. Lawrence valley (Beverly, Ont,) in the bluntness of the 
 dorsal valve behind, and in the possession of a median sulcus ; the valves 
 _ of the Cape Breton form also have a scabrous surface. The ventral is 
 flatter at the umbo and in both valves the muscle scars are in a more 
 advanced position than they are in L. acuminata. 
 
 From L. pinnoe/ormis of the St. Croix sandstone it differs in its rougher 
 surface, less acuminate umbo, and in the advanced position of the central 
 muscle scars. 
 
 From L. cuneola Whitfleld it differs in its larger size, greater flatness, 
 and more obtuse umbo of the dorsal valve. la form and size it is inter- 
 mediate between L. acuminata and L. cuneola. 
 
199 
 
 LiNGDLEPIS ROTUNDA, n. sp. PI. XIV, figs. 4 a-f. 
 
 Minute, valves tumid : the ventral ovate-acuminate, the dorsal nearly Lingnlepis 
 , . , rotunda 
 
 orbicular. described. 
 
 Ventral valve rather bluntly pointed, and marked by undulating ridges 
 of growth, irregularly spaced. Interior. — The hinge area is high and has 
 a distinct pedicle groove, narrow deltidium and wide marginal area. The 
 visceral callus extends half way of the length of the valve, and here the 
 central group of muscles are placed. Divergent ridges on each side of 
 the visceral cavity indicate the position of the lateral scars ; and f r6m 
 these ridges extend forward, arching toward the front of the valve, faint 
 impressions of the vascular trunks. The margin of the valve is flattened 
 at the sides and in front. 
 
 The dorsal valve is nearly circular in outline and strongly arched ; the 
 slope is most abrupt toward the lateral margins, and the valve is somewhat 
 flattened on the front slope. Interior. — No hinge area is apparent on this 
 valve which is almost vertical at the cardinal line. Two small pits near 
 the hinge are in the position of the lateral muscles ; from here a broad 
 medium septum extends nearly to the anterior third of the valve ; on 
 each side of this ridge are prints of the central muscles and at its extre- 
 mity those of the anterior laterals. Lateral ridges more widely set, and 
 less divergent than those of the ventral, separate the scars of the lateral 
 muscles from the visceral cavity. In front of the lateral ridges are faint 
 impressions of vascular trunks, that go somewhat directly toward the 
 front margin. The edges of the valve at the sides and front are flattened. 
 
 Sculpture. — The outer surface of the ventral valve shows traces of 
 growth ridges, but nothing of this sort was observed on the dorsal, which 
 is covered with a minute tuberculation. 
 
 Size. — Length of the ventral, 4 mm.; width, 3 mm. The dorsal is 1 
 mm. shorter than the ventral. 
 
 Horizon and locality. — In gray flags of the middle division (Div. C, 2 c) Resembles O. 
 on the eastern slope of the valley of McNeil brook (on the road to Trout ^'j"'™*^**^ 
 brook) Mira river, Cape Breton, N.S. 
 
 This species appears to be near 0. (L.) rotundatus, Wale* but differs 
 in its longer ventral valve and in the extremely narrow cardinal area to 
 the dorsal valve. ' 
 
 *U. S. Nat. Mus. Proo. vol. xxi, p. 415, 
 
200 
 
 LiNGULELLA LiEVis var. GEANDis, n. var. PI. XV, figs. 1 a-d. 
 
 Lingulella -A- large Lingulella of the form of the species described in Illustrations 
 
 laevisyar. of the Fauna of the St. John Group* was found at Escasonie. Only 
 grandis _ \ _ . ■' 
 
 described ventral valves were obtained, and with one of them is here described an 
 
 interesting ventral from the _ same horizon at St. John and which is 
 
 thought to be of the same species. The valve from St. John shows what 
 
 appears to be the pedicle, and its sinew within the shell. 
 
 Ventral valve. Central valve broadly ovate with a bluntly pointed, rather high (but 
 poorly preserved) cardinal area. The valve is thin and is evenly arched 
 down in all directions from the centre. The details of the interior are 
 somewhat obscured by the dorsal valve which was pressed down upon it. 
 Interior.^A visceral callus, pointed in front, is outlined ; this shows the 
 position of the cardinal muscles. The transmedian (d) and lateral mus- 
 cles (e) are shown by faint scars and inside them, on each side of the 
 valve a low ridge (/) extending forward nearly to the lateral margins ; at 
 the extremity of these ridges is what appears to be the print of a muscle 
 scar ; it is oval, is within the ridge and directed diagonally forward. 
 
 The sinew of the pedicle appears to be preserved in this specimen as a 
 dark sinuous line, originating at a point {k) where in ventral valves of 
 several species of this genus, a small scar has been observed, and extend- 
 ing out through the pedicle groove (a). From the beak of the shell it can 
 be traced over the surface of the layer of shale on which the shell is pre- 
 served to the margin of the shale fragment containing the fossil. The 
 sinew or muscle within the shell has a diameter of about J mm. The 
 pedicle itself outside of the beak of the shell, is considerably larger than 
 the pedicle groove at the beak ; it is composed of at least three elements 
 — a central thread of dissevered particles of black, shining, carbonaceous 
 tissue ; this is perhaps a condensation of the coelon substance. It is en- 
 circled by a space showing but little organic matter ; external to this is a 
 tube of strong black tissue, not shininglike the central thread, but of com- 
 pact and continuous substance ; external to this tube, there appear traces 
 of organic matter which may be the remains of a fleshy and perishable 
 covering. The diameter of the pedicle is about f of a millimetre near the 
 pedicle groove ; the part of the pedicle preserved is 3 mm. long. 
 
 Dorsal valve. The dorsal valve from Escasonie, like that above-described, is quite thin, 
 both at the visceral callus and elsewhere ; it is most strongly arched in 
 the posterior half, but flattened on the lateral slopes (this in so thin a shell 
 may be due to pressure after entombment). The form is broadly ovate 
 but blunted at the umbo. 
 
 *Tran8. Roy. Soo. Can. vol. ix, sec. iv, p. 39, pi. xii, fig. 4 a-b. 
 
201 
 
 Interior. The cardinal area is high and has about seven furrows whish 
 are arched forward at the sides to tlie deltidial ridges (6) ; the areal 
 borders {a) are thick and flattened. A small umbonal muscle-scar % (c) is 
 found just within the hinge-line ; but at the sides of the area within the 
 body cavity are stronger prints (t/) which may be interpreted as paired 
 cardinal scars or perhaps transmediaa scars. The central muscles (A.) are 
 about two-fifths of the length of the valve from the back, and are rather 
 close together ; and the anterior laterals {j) are nearly as far forward as 
 the mid length of the valve ; a median septum (i) divides both pairs of 
 muscle scars ; there is a faintly marked median sinus (m) in the anterior 
 third of the valve. The trg,nsmedian muscle scars (ig) are small compared 
 with those of most species of Lingulella and nearly as far forward as the 
 centrals Qi). Two small scars behind the transmedian appear to be those 
 of the I and h laterals. Faint impressions of the vascular trunks (k) ex- 
 tend forward in a regular arch, rather near the margin of the valve. 
 
 The central scars in this valve are approximated as in Lingulella, not 
 spread as in Obolus. 
 
 The surface of the callus shows abundant pitting as in Lingulella 
 Davisii and other species of Lingulella and Lingulepis. 
 
 Sculpture. The surface of the valves is shining and smooth, except for 
 shallow crescent-shaped grooves and more distinct growth lines ; these are 
 more distinct on the lateral and front margins than elsewhere. Besides 
 these markings, a strong lens reveals a minute granulation all over the 
 surface. 
 
 Size. Length of the ventral valve (from St. John), 21 mm.; width. 16 
 mm ; length of the dorsal (from Escasonie), 17 mm.; width, 14 mm. 
 
 Horizon and locality. From layers of fine sandy shale of Div. 3a. 
 
 Salters' original figure of L. Davisii in the Memoirs of the Geological Compared 
 Survey of Great Britain, shows that that species like this one, was pitted p^^g^] 
 over the visceral region,* and it is nearly of the size of these shells, but 
 these do not exhibit the " satchel shape," supposed to be characteristic 
 of that species, and which we find in the species next described from a 
 higher horizon. (See page 203). 
 
 The position of the muscle marks in these valves may be compared with 
 those of L. Davisii as figured by Mr. Walcott.f 
 
 Var. lens, pi. XV, figs. 3a-A. 
 
 Lingula (?) lens Bull Nat. Hist. Soc. of N. B., vol. IV, page 274, pi. 
 V, figs. 3 o to A. 
 
 *Mem. Geol. Surv. Great Britain, vol. 3, pi. 2 fig. 11 a and pi. 4, figs. 14 and 14 a. 
 tU.S. Nat. Mus. Proced. vol. XXI, pi. XXVII figs. 1 and 2. 
 
202 
 
 Description 
 of var. lens. 
 
 Sculpture. 
 
 Shell substance calcareo-comeous. A broadly ovate form with rather 
 thin, smooth valves, having flattened lateral slopes in the ventral valve, 
 and being somewhat tumid toward the umbo in the dorsal valve. 
 
 Ventral valve rather blunt at the umbo, whence for about one-third of 
 its length the curve of the margin is somewhat straightened ; for the rest 
 of the border it is regularly rounded to the front ; the greatest width is 
 a little in front of the mid-length. The umbonal ridge extends about half 
 of the valve, whence to the hinge the sides of the valve are flattened ; in 
 front of the middle of the valve the slopes are evenly but flatly arched 
 down to the margin. Interior. — The position of the central group of 
 muscles is within the posterior third of the valve, and the position of the 
 laterals is indicated by a bounding ridge ; these features are very faintly 
 marked. 
 
 The dorsal valve is broadly ovate, and its slopes are more strongly 
 arched in the posterior half than elsewhere, otherwise it is like the ven- 
 tral. Interior. — This has a sharp, low septum for half its length, and on 
 each side a parallel ridge, extending to the middle of the valve ; at half 
 the length of these ridges are small lenticular scars, and at their outer 
 ends the group of central muscles. The lateral muscles are opposite the 
 middle of the median ridge. 
 
 Sculpture. — The outer crust in this species is normally smooth in 
 appearance, but is beset with minute pits, and has a very minute con- 
 centric and radiating striation. The sculpturing of the layer beneath 
 has impressed itself on the outer layer in different parts of the surface ; 
 at the sides and in front we find concentric ridges, and in the middle 
 third the imprint of the vascular sirise that run toward the front margin. 
 These markings are much more distinctly shown on the under layer. 
 
 Size. — ^Length of the ventral valve, 16 mm. ; width, 13 mm. The dor- 
 sal valve is 1 mm. shorter than the ventral. 
 
 Horizon and locality. — Thin calcareous layers in the flags of Div. 3a 
 at MoAdam shore, Escasonie, Cape Breton. The shell in these layers are 
 freely intermingled with small lumps and particles of calcium phosphate. 
 The phosphate lumps are frequently moulded on the shells, or entirely 
 enclose them ; though some shells are enclosed in the phosphate, others 
 are free, and with fragmentary shells are mingled with the sand. Other 
 masses of the phosphate are entirely free of the shells, and are smooth 
 and shinipg, as though rolled on the beach ; yet the flat, oval, or rod-like 
 pieces of the phosphate seem the natural form which the substance as- 
 sumed when in a gelatinous condition. Probably the formation of the 
 phosphate was cotemporary with the entombment of the shells. 
 
203 
 
 This shell differs from the type in the more obtuse and tumid umbo 
 of the dorsal valve and the heavier and more prolonged umbo of the ven- 
 tral valve. 
 
 LiNGULELLA, cf. Davisii, McCoy. 
 
 Examples of a Linguella which though smaller than the above species Lin^ella cf. 
 of the Lingula flags and Tremadoc slates of Britain, has the same gene- 
 ral form, are found in the Asaphellus beds of Cape Breton. It has the 
 nearly straight base and sub-parallel sides of McCoy's species. The dor- 
 sal valve has on the interior a median septum two-fifths of its length, 
 and the whole interior, especially towards the umbo, is marked with scat- 
 tered pits. 
 
 Sculpture. — Externally this shell has fine concentric ridges, which are 
 crossed by very fine radiating striae. The middle third is marked by 
 numerous, fine, radiating, vascular lines, and the lateral borders are flat- 
 tened at the sides. 
 
 Size. — Length, lOJ mm. ; width, 9 mm. Infrequent. 
 
 Horizon and locality. — In the gray shale of Assise C. 3 c^, at McLeod 
 brook, Boisdale, N.S. 
 
 LiNGULELLA CONCINNA, PI. XIV, figS. 5flS-6. 
 
 Lingulella concinna, n. sp. Bull. Nat. Hist. Soc. of N. B., vol. iv p. 273 
 pi. V, figs. 2 a and h. 
 
 Occurring in the dark gray shales of the Upper Cambrian on McLeod Lin^ullela 
 brook are a few examples of a small Lingulella, smoother than the species described, 
 from the same beds referred provisionally to L. lepis, but ornamented, as 
 that species is, by concentric ridges. 
 
 The shell substance is quite thin towards the lateral and front margins, 
 and is there flattened out by pressure. The beak is somewhat blunt, and 
 the rounded lateral margins give the ventral valve an ovate form. 
 
 Sculpture. — Over the visceral space the surface of the valves is covered 
 with very fine concentric somewhat lamellose ridges, visible with a lens ; 
 over the branchial area these ridges fiatten down, and the valve has a 
 shining granular surface ; the ridges, however, remain distinct on the 
 lateral margins, though there also the surface is bright. 
 
 * Introduction to study of Brachiopoda, Hall & Clarke, p. 229 ; fig. 23, and pi. 2, 
 fig. 5. 
 
 t U. S. Nat. Mus. Proo. vol. XXI, p. 385. PI. xxvi; fig. 1. 
 
 {Imp. Acad, dea Sci., St. Petersburg. Ser. VIII, Tom. iv, No. 2. PI. II, figs. 
 19c and 21e. 
 
cf. lepis. 
 
 204 
 
 Size. — Length of the ventral valve, 8 mm. ; width, 6 mm. The dorsal 
 valve is nearly 1 mm. shorter than the ventral. 
 
 Ifonzon and locality. — In the fine dark gray shales of Div. 3c, at 
 McLeod brook, Boisdale, N.S. Scarce. 
 
 Not the same Mr. Walcott has referred this species to his 0. (L.) bellus* -which was 
 
 as O (L) 
 
 bellus published without figures. I may say, however, that I have compared 
 
 Walcott. j(; ^j^]j Walcott's species, and find that it is smaller, has finer growth 
 
 lines, and they are more sharply defined on the surface. 
 
 LiNGULBLLA, cf. L. LEPIS, Salter. 
 
 cf. Lingulella lepis Salt. mem. Geol. Surv. Great Britain, vol. iii, p. 538, 
 
 fig. 11. 
 
 Lingulella A species which by its size and sculpture appears to agree with this, is 
 
 common in the Dictyonema shales both in Cape Breton and in southern 
 New Brunswick ; it is also found in the beds below this horizon, for 
 in the assises 3a and 36 in the St. John basin, are many examples of 
 similar shells, but they are so distorted and flattened as to be unrecog- 
 nizable. 
 
 Lingulella eadula, var. aspeea n. var. PI. XV, figs. 2 a to cf. 
 
 Lingulella Mingled with the shells of L. radula in the flags of Div. 2c at Courtney 
 
 d^soriptionrf. bay, St. John, N.B., are the valves of a smaller species, which in the 
 description of the fossils from that locality was spoken of as a variety of 
 that species, t It appears to agree in form, size and markings with a 
 small species from the flags of Mira river, Cape Breton, which is here 
 described. 
 
 A small ovate species, ventral rather flat, dorsal tumid. 
 
 The ventral has an acute projecting beak, but elsewhere the relief is 
 flattened, and gently sloped to the margin. Interior. An example 
 partly exfoliated shows a strong pedicle groove and rather high area. 
 The cast of the interior exhibits a thickened visceral callus extending 
 less than half of the length of the valve, with impressions of the central 
 muscles about two fifths of the length of the shell from the apex. Faint 
 imprint of the vascular trunks are traceable, extending to one quarter of 
 the length of the valve from the front. 
 
 The dorsal valve is strongly convex, and has flattened margins on the 
 under side. Interior. The cardinal area is rather high, being about one 
 
 *Proo. U. S. Nat. Mus., vol. xxiii, p. 685. 
 
 t Trans. Roy. Soo. Can., vol. viii, sec. iv, p. 148. 
 
205 
 
 twelfth of the length of the valve. The central group of muscle scars is 
 rather large and lies at the bottom of the deep cavity of the valve ; the 
 anterior laterals (j) are a little more than a third from the front of the 
 valve. Distinct impressions of vascular trunks may be seen on each side 
 toward the margin of the valves. 
 
 Sculpture.— The outer surface appears dull and without lustre, but in 
 proportion to the size of the shell, it is coarsely granulated, and towards 
 the margins has indistinct ridges parallel thereto. 
 
 -Size.— Length of the ventral 5 mm. ; width 4 mm. The dorsal is J 
 mm. shorter. 
 
 Horizon aud locality.— CoWected by M. A. H. Foord on the Mira river 
 m 1874. The special locality is not given, but the matrix is a fine mica^ 
 ceous sandstone like the flags of Div. C. 2 c. 
 
 The resembling form mentioned above as occurring in the St. John Compared to 
 flags at Courtney bay is somewhat smaller but has a similar radular °**'®'" sp^oies. 
 ornamentation. 
 
 This species is nearly as large as that described by Mr. Walcott as 
 (L) hellulus from Kellys island. Conception bay, Newfoundland.* 
 
 This latter species is the same as that described by Dr. Whiteaves 
 many years ago from that locaKty under the name of Lingula BiUings- 
 ana. I have co-types of this species and of L. hellulus, buti do not find 
 on the Cape Breton species described above the fine irregular strise 
 said to be characteristic of the latter. It is also a comparatively wider 
 species. 
 
 WESTONIA, subgen. Walcott. 
 
 " Ovate, with ventral valve slightly accuminate ; area of ventral valve Sub-genus 
 strongly defined, and divided by a relatively large pedicle groove. Sur- ■V73*°tt* °* 
 face marked by concentric and radiating striae that are crossed by trans- 
 verse semi-imbrica£ing ripple-embossed lines. As far as known, the muscle 
 scars and vascular markings are essentially the same as in Obolus." 
 
 Mr. Walcott takes for the type of this subgenus 0. aurora of the St. 
 Croix sandstone (upper part) and with this, his diagnosis agrees. And he 
 includes Lingulella (?) lens of the Cape Breton fauna, with which the 
 description of the subgenus does not agree in several respects, e.g. the 
 ventral valve is not acuminate but is bluntly pointe3, the area though 
 well defined, is not high, being about one seventh of the length ; and 
 
 *Proo. U.S. Nat. Mus. vol. xxi, p. 398 (no figure). Am. Jour. Sci. 3 Ser. xvi, 78, p. 
 226. 
 
206 
 
 the transverse ridges are not imbricated, but smoothly rounded. The 
 character of the hinge of the dorsal of L. Hscasoni is quite different from 
 Obolus. The area is quite low and the posterior end of the valve rounded 
 steeply down ; whereas in Obolus the area is high and that end of the 
 valve flat. 
 
 Also in the ventral valve the scar of the central muscles is triangular 
 as in Lingulella, not rounded in at the sides as in Obolus. For these 
 reasons, if L. (?) Escasoni is to be included in Westonia, to me the sub- 
 genus would seem to be related to Lingulella rather than to Obolus. 
 
 The ornamentation of peculiar transverse waving ridges, however, is a 
 convenient common character that unites a number of forms and so is 
 useful as a feature held in common, and due to a like origin, in these 
 beautifully ornamented shells. 
 
 The Canadian species being of the Peltura Zone is a little older than 
 O. (L.) aurora, which being associated with Dicellocephalus Minnesotensis 
 should be within the Tremadoc Zone. 
 
 Westonia Escasoni. PI. XVI., figs. 1 a-h. 
 Nat, Hist. 800. of N. B. Bull. vol. iv, p. 270, pi. v, figs 1 a-c Matt. 
 
 :^casoni* " Corneous, but having a thin outer calcareous layer. The inside of 
 
 described— the edges of the valves is flattened, 
 ventral valve. 
 
 Ventral valve ovate, pointed at the apex, somewhat elevated from the 
 umbo, along the axial line. Interior. — Cardinal area short, traversed by 
 a depressed pedicle groove. The cavity between the umbo has impres- 
 sions of two small, cardinal muscles, from which radiate two grooves. 
 
 The ventral bordered outside by ridges that separate the lateral muscle scars from the 
 valve. ... 
 
 visceral cavity. The print of the central muscle is oval or lenticular and 
 
 transverse to the axis of the valve ; it is divided lengthwise, half way, by 
 a septum ; the posterior half of the scar is again divided by a faint ridge 
 at right angles to the septum named. The "1" laterals are small trian- 
 gular imprints in front of the outer part of the central muscles. In some 
 valves the paired scars of the "k" laterals at the middle of the central 
 group are small, and behind them extending toward the umbo is a sharp 
 furrow enclosed between narrow ridges ; in others they are wider and the 
 ridges are not preserved. The grooves of the lateral muscles are discern- 
 able near the hinge on each side; the transmedian ("i") being external 
 and on the inner edge of the flattened margin of the valve ; the (" j ") 
 laterals are on the slope of the valve within the flattened margin. 
 
207 
 
 The vascular trunks extend forward in a regular arch from the middle 
 of the valve a little withia the flattened margin, which is creased trans- 
 versely by about a score of closely set parallel grooves. In the anterior 
 third these give place to grooves that are at right angles to the margin ; 
 these correspond in course to the faintly impressed sub-parallel 
 grooves that extend from the front margin across the middle of the valve 
 to the visceral callus. Faint traces of branches of the vascular trunks 
 are seen on the slopes of the valves in the anterior half. 
 
 The dorsal valve is of an oval form. It is strongly arched down in the Dorsal valve. 
 posterior half, but less so on the anterior slopes. Interior. — This shows 
 at the cardinal lines a depression in which are a pair of circular pits, due 
 to the cardinal muscles. Between these pits, on the axial line, is a small 
 pit from which two sharp low ridges run forward ; at one-third from the 
 back of the valve there is a minute scar between these ridges ; and outside 
 of them in the posterior half of the valve are the large oval prints of the 
 central ( " h " ) muscles ; these are set somewhat diagonally to the axial 
 line, having the fronts turned outward. At the anterior ends of the 
 median ridges are the small scars of the anterior lateral ( " j " ) muscles. 
 Paint diverging ridges extend from the umbonal cavity toward the lateral 
 margins of the valves ; at one-third from the back, partly on and partly 
 outside the ridges are the large but rather faint imprints of the posterior 
 lateral muscles. 
 
 This valve, like the ventral, has flattened margins on which are imprint- 
 ed minute, closely set, transverse grooves. 
 
 Sculpture. — The sculpture of the true outer surface of this species is Sculpture, 
 not easily found ; it is imprinted on a thin calcareous, fibrous layer, which 
 is usually broken away, revealing the next layer of the shell. The outer 
 layer is crossed transversely by closely set striae, forming ridges, of which 
 there are about nine or ten in the space of a millimetre ; some of these 
 ridges have cross striae at intervals ; others anastomose, and all have a 
 roughened surface ; the ridges have a waving course over the middle 
 third of the shell, but elsewhere are comparatively straight. 
 
 Beneath the outer shell is a corneous layer whose sculpturing conforms 
 to that of the outer layer, but the strise are wider and the intervening 
 ridges narrowed ; this layer has a shining surface. Beneath this is a 
 third layer on which the striae run in an opposite direction from those of 
 the one above, the sculpturing, especially along the central part of the 
 valve, consisting of strise radiating from the umbonal region to the front 
 margin ; these are crossed at intervals by undulations of growth concen- 
 tric to the umbo ; on the inside of this layer are impressed the surface 
 markings of the interior of the valves. 
 
208 
 
 Compared 
 with other 
 species. 
 
 Size. — Length, 5 to 5i mm. ; breadth 4 to 5 mm. ; depth of each valve 
 about 1 mm. The ventral is aboiit J mm. longer than the dorsal. One 
 dorsal has a length of 6 mm. 
 
 Horizon aud locality. — In calcareous sandy layers with the Peltura 
 fauna (C. 3 6.) at Mo Adam shore, Escasonie, Cape Breton. This species 
 was not found in situ, but in loose pieces of thin flag in the shingle of the 
 shore where the trilobites occur : these pieces were very little worn, and 
 therefore near or at the parent ledge. This species may be referred to 
 the Peltura Zone, (0. 36). 
 
 This species is referred doubtfully to Lingulella as it has some characters 
 of other genera. The weak cardinal development is like Leptobolus ; as 
 is the long lateral ridges and advanced (" j ") laterals of the dorsal valve. 
 The spreading vascular trunks of the ventral valve are like Leptobolus 
 and Obolus, as also the advanced " j " lateral. On the other hand the 
 thick shell is quite unlike Leptobolus, but common in Obolus and Lin- 
 gulella. 
 
 This pretty little species is easily recognized by its peculiar transverse 
 sculpture. Lingula tceniola, Hall, has a similar transverse ornamenta- 
 tion, but is much larger, and flourished at a later period (Clinton 
 group).* 
 
 Lingulella Ella, H. and W., has a somewhat similar sculpture, but is 
 distinguished by its greater size and closer approximation of the vascular 
 trunks of the ventral valve. 
 
 It is only in a few valves out of many that we find distinct muscle 
 scars, enabling us to compare the species with others. Michwitz has 
 determined that the exterior half of the central muscle in the ventral 
 valve of Obolus represents the " 1 " lateral of Lingula. f In this relation 
 it is interesting to observe that the great muscle in L. (?) Escasoni also 
 has a septum partly dividing it ; but there is a separate scar, a small 
 triangular one, at the anterior outer angle of the great muscle, which 
 with more probability may be considered the external lateral or " 1 " 
 muscle ; the large oval muscle would then be the " h " central (with possi- 
 bly the " k " lateral involved), but it would consist of three main strands; 
 for beside the septum across the middle at the back, the scar is divided 
 by a more obscure transverse ridge parallel to the long diameter of the 
 scar. This muscle then may be compared to those of Lingula, etc., having 
 divisional lines. | 
 
 * New York State Geologists' Report. Hall & Clarke, 1891, pi. 1, fig. 8. 
 
 t Mem. Acad. Imp. des Sci. St. Petersburg. Series VIII. Tom. IV., No. 2, p. 79. 
 
 J Introduction to study of Brachiopoda, Hall & Clarke, p. 229 ; 23, and pi. 2, fig 6. 
 
209 
 
 In 0. (L.) ccdatus, Volb., we see an arrangement of muscle scars in 
 the central group of the ventral valves similar to that in L. (1) Escasoni* 
 Here Mr. Walcott interprets the small scar as an external lateral („ 1 "), 
 but the larger one as a middle lateral ("k"). Volborth's figure of this 
 species does not show the small scar, but he appears to allude to it in the 
 text where he says that " the several laterals of the ventral valve are not 
 80 closely bound together as in the subgenus Euobolus. t" 
 
 LINNAESSONIA, Wale. 
 Obolus. 
 
 An orbicular brachiopod (a single valve) was found in the flags of Div. An Oii jUis. 
 (C. 26.) on the east side of the Long Island passage. The material is not 
 sufficient to determine the species. 
 
 LiNNABSSONiA, cf. Belti, Davidson ? PI. XVI. figs. 3a-c. 
 
 Linnarssonia Belti, Dav. 1 Trans. Roy. Soc. Can. vol. ix, p. 42, pi. xii 
 
 figs. "ac. 
 
 The shell of the St. John Basin referred to this species, has the follow- 
 ing characters : — 
 
 Shell oblately orbicular. Test corneous. 
 
 The dorsal valve (?) resembles that of the shell [0. misera ?) in the zone Linnarssonia 
 (C. Id) of the St. John Group, being like that of an Acrotreta in its in- "^' ^®^*^' 
 ternal markings. 
 
 In the ventral valve we do not see the strong scars and V-shaped ridge 
 at the umbo, of the typical forms of Linnarssonia, but in their place 
 small scars, and two faint V-shaped lines extending from the umbo. 
 
 Sculpture. — The surface of the shell is marked with fine concentric and 
 less distinct radiating lines, or is smooth. 
 
 Size. — Length 3 mm. ; width 3J mm. 
 
 Horizon and locality. — From fine gray shales of the Dictyonema beds 
 (Div. C. 3c) at Navy island, St. John harbour. 
 
 This little shell is distinguished from those that occur with it (except 
 Acrotreta), not only by its form, but also by the extreme tenuity of its 
 test, thickened only at the umbo. In this also it resembles the shell from 
 Civ. (C. Id) referred to above, and those of the genus Acrotreta. 
 
 * U. S. Nat. Mus. Proc. Vol. XXI., p. 385, PI. xxvi., fig. 1. 
 
 t Imp. Acad. des. Sci., St. Petersbourg. Ser. VIII., Tom. iv., No. 2. PI. 11., figs. 
 19c and 21c. 
 
 14 — C. R. 
 
210 
 
 Resembling This shell is referred provisionally to Oholella Belti, Dav., of the Lower 
 
 species. Tremadoc in North Wales, which is about the horizon of our species. 
 
 Davidson remarked that the " internal characters agree pretty closely 
 with those of 0. sagittalis." On comparing Davidson's figures of the 
 ventral valves of 0. Belti and 0. sagittalis, one may remark differences 
 similar to those which distinguish 0. (L.) misera, Bill, from 0. (L) trans- 
 versa, Hartt, of the St. John Group. Tn 0. Belti and 0. misera the muscle 
 scars are fainter and nearer the back of the shell, and the umbonal callus 
 is smaller than in the other two. 
 
 This species is not common at McLeod brook. The V-shaped ridge 
 of the ventral valve runs about half way to the front, and is more U- 
 shaped than with the other species. 
 
 The ventral valve has a strongly marked median ridge in the middle 
 third of the length of the valve, in front of this the ridge extends as a 
 low elevation nearly to the front margin. Opposite the high part of the 
 ridge, in the posterior third of the valve, are two strong triangular pits 
 which appear to be muscle scars. The posterior lateral margins of the 
 valve are flattened. 
 
 Sculpture. — Often the surface is finely granular, and the dorsal shows 
 a few concentric ridges of growth. 
 
 Size, as stated above. 
 
 Horizon and locality. — Fine dark grey shales of Div. (C. 3c,) at Mc- 
 Leod brook, Boisdale, Cape Breton. 
 
 N.B. — Mr. Walcott, who has examined the examples from I^avy island 
 says they are not L. Belti, Dav. 
 
 Monobolina 
 refulgens. 
 
 MONOBOLINA, Salter, 1865. 
 Monobolina refulgens. 
 
 PI. XVI. figs. 2a-J/, alsu PI. XI. figs, ia and b. 
 Obolus refu/gens, Matt. Trans. Roy. Soc. Can. vol. ix sec. iv page 44, pi. xii, figs. 6a-d. 
 Since the description of this species was written, in 1890, no observa- 
 tions had been made which would define more accurately the internal 
 characters of this shell, or throw additional light on its affinities. The 
 more perfectly preserved shells collected lately in Cape Breton, however, 
 have changed the writer's view of the relation of this species. 
 
 A sharply preserved mould of the dorsal valve shows that the species 
 is congeneric with Oholella (Monobolina) plumbea of the "Welsh Lower 
 Ordovician, characterized by the close approximation of the central 
 
211 
 
 muscles of the dorsal valve. In Obelus, sens, strict., these muscles are 
 well apart. 
 
 The following is the original description of this species : — 
 
 Shell oblately 'orbicular, lenticular, edges thin, sharp, flat. Test corneous, 
 surface brilliant. 
 
 The ventral valve is produced at the back into a low, rather blunt beak. Description of 
 depressed at the point. In the interior of the ventral valve, there are at 
 the back three ridges, which diverge from the umbo ; of these the mesian 
 ridge dividing the posterior adductor muscles, is short and weak ; it is 
 forked at the end (where it terminates against the scar of the pedicle 
 muscle 1) The two lateral ridges are longer, being about one-quarter of 
 the length of the shell, and are more distinctly outlined, by a long narrow 
 pit on the inner side. The visceral cavity is wide in front and terminates 
 in a long sinus ; some specimens show in this sinus a muscular callosity. 
 The hinge area is narrow, and deflected downward in the middle. Ifc is 
 crossed by a shallow pedicle groove. 
 
 The dorsal valve has at the hinge a very thin edge, turned inward. The 
 interior is marked by three diverging ridges, of which the central is longer 
 than the lateral ones. The central ridge when well preserved, appears to 
 extend two-thirds of the length of the shell, and is distinct as far as the 
 middle of the shell, where there are two small muscular impressions ; at 
 the back of the shell, between the mesian and lateral ridges, are the 
 impressions of the [posterior] adductor muscles. There is a large shallow 
 bilobed depression in the anterior half of the shell. The cardinal border 
 is thin and is made much more distinct by a pair of small narrow trans- 
 verse pits, one on each side of the mesian ridge. 
 
 Sculpture (1 ). — The surface is marked by very fine concentric and radiat- 
 ing lines, and there are stronger concentric growth lines at intervals on 
 the surface. 
 
 Size. — Length of the ventral valve 8J mm. ; width 10 mm. The dorsal 
 valve is half a milimetre shorter than the ventral. 
 
 Horizon and locality. — In the Dictyonema shales (Div. C. 3c) Navy 
 island, St. John harbour. 
 
 No very, satisfactory examples of the marking of the interior of the 
 valves were found, in any one individual ; but by combining the markings 
 found on several valves of the dorsal and ventral sides respectively, it has 
 been found possible to restore some of the features of the interior of the 
 shell." 
 
 14|— c. B. 
 
Features of 
 tlie interior. 
 
 Sculpture of 
 the surface. 
 
 212 
 
 There is little to add to the description of the ventral valve, but the 
 small size of the space occupied by the muscles is remarkable. The height 
 of the cardinal area is only about one-eight of the length of the valves, 
 which is not the case in Obolua. 
 
 A mould of the interior of the dorsal valve from McLeod brook, shows 
 much more distinctly than those from the St. John basin the nature of 
 the impressions of the central muscles ; and the crowding together of 
 these scars, corresponding to the description of Monobolina by Salter. 
 Although there is sometimes a faint elevation on the median line in the 
 anterior of the valve, the median ridge cannot be said to extend beyond 
 the mid-length of the valve, and it is bordered by two deep and narrow 
 grooves in the anterior half of its length, that separate the print of the 
 anterior adductors, which in their turn are bordered outside by a shallow 
 groove, as represented by Davidson for Monobolina plumbea. The poste- 
 rior half of the mesian ridge is much fainter than the anterior ; in fact 
 the posterior half of it is almost obsolete. 
 
 The position of the central group of muscles in the dorsal valve of this 
 species (M. refulgens) as well as the short visceral callus of the ventral 
 valve, appear to exclude this species from Obolus, and show its neareness 
 to, or identity with Monobolina. Moreover, the weak muscle scars, and 
 the absence of an area to the dorsal valve, are also not found in Obolus. 
 
 Sculpture (2).— The state of preservation of the examples from Cape 
 Breton, give a much better knowledge of the surface characters of this 
 species, than those from Navy island. The surface was spoken of as 
 " brilliant ", but this brilliancy is found on the second layer of the shell ; 
 the Cape Breton examples appear to have a thin outer prismatic layer of 
 mineral matter, which (if not an accidental addition) is a dull surfaced 
 outer layer, which when viewed with a strong lens exhibits a finely gra- 
 nular surface, ornamented with concentric ridges ; these ridges are low, 
 often interrupted or broken, and separated by smooth granulated spaces. 
 The under corneous layer is aho marked by concentric undulations of 
 growth, and towards the front of the shell, and especially on the inner 
 surface of this layer, by numerous sub-parallel lines, radiating from the 
 umbo. There is still another layer of the shell which forms its inner sur- 
 face, and on which the muscle scars and vascular trunks are impressed. 
 
 I more than suspect that the surface which Mr. Salter described as 
 that of Oholella (Monobolina) plumbea is the corneous surface of that 
 species, corresponding to the similar one in this.* 
 
 *Mem. Geol. Surv., G. Britain, vol. iii, p. 539, London, 1881. 
 
213 
 
 Size. — Length of the ventral (of M. refulgena) 9 J mm. ; width, 11 mm.; 
 length of dorsal nearly 9 mm. 
 
 Horizon and locality. — In the fine dark gray shales of Eand C. 3 c, at 
 McLeod brook, Boisdale, N.S. Common. 
 
 Comparing the species with M. plumbea, there is a considerable differ- Compared 
 ence in size, Salter's figures being of the natural size. Davidson's figures plumbea. 
 show a shell about as large as the largest of M. refulgens. The proportion 
 of the outline of the valves given by Salter of 3 to 4 are different from 
 our species in which the proportion is about 5 to 6 ; the Cambrian species 
 therefore is rounder than the Ordovician. But Davidson's figure has nearly 
 the same proportion as the Cape Breton form. In Salter's species the 
 cardinal area of the ventral valve is higher, and the visceral cavity pro- 
 proportionately larger than in this specias. 
 
 Salter records a variety of M. plumbea ( plicata, Hicks) as occurring 
 in the Tremadoc group,* which would come almost within the range of 
 M. refulgens ; and forms like the latter have been seen as low down as 
 the Assise a of Division 3 of the St. John Terrane. 
 
 ORTHIS. 
 
 Okthis lenticularis, Dalman, PI. XVII, figs. 1 a-d. 
 
 1821. Atrypa lenticula/ris Wahl., Petr. Tell. Suec, p. 66. 
 
 1827. Atrypa lenticularis Dalm., Vet. Acad. Handl. p. 132; Hist. Leth. 
 
 Suec, p. 76. 
 1834. Spiri/er ? lenticularis L. von. Buch., Abhandl. d. Berl. Acad. p. 48 
 
 Tab. i, figs. 13-14. 
 1857. \ Atrypa lenticularis. Jijerulf., Geol, d. Siidl. Norw. p. 284.; Vei- 
 
 1865. / viser <fec. p. 1-3, fig. 7. 
 
 1866. Orthis lenticularis Dav., Geo. Mag. vol. v. tab. xvi, figs. 20-22. 
 1871. Orthis lenticularis Dav., Brit. Silur, Brach. p. 230, tab. xxxiii, 
 
 figs. 22-28. 
 1891. Orthis lenticularis. Wahl., Trans. Roy. Soc. Can. vol. ix, sec. iv, 
 p. 48, pi. xii, figs. 9 a-d. 
 
 The following is Wahlenberg's original description of this species : — OnhU 
 Suborbicular, on each side a little convex, radially undulate. In a '™*'°"1^"'*- 
 " suillous " • rock [fetid limestone] in beds of aluminiferous slate, in 
 which material do other shell has been found. It occurs plentifully every- 
 where throughout several provinces. In size and in its situation resem- 
 bles at first sight the pea-shaped entomostracan [Agnostus pisiformis] 
 
 *Mem. Geol. Surv., G. Britain, vol. iii, pp. 355, 368. 
 
214 
 
 which occurs in the same rock. Each valve possesses an equal con- 
 vexity, so that when united they very much resemble the seed of a lentile. 
 The valves are seen to have been very thin in their substance. 
 
 Dalman's description is fuller, and is as follows : — " A small species 
 with very slender and fragile valves. Length about 4 mm., and of about 
 the same, or somewhat greater breadth. An entire specimen is rarely 
 found, but the species is very easily distinguished on account of the 
 stone in which it occurs, as it has scarcely any other species of Tere- 
 bratulite with it. The shell is suborbicular, with the base somewhat 
 j)rominent, and a little convex ; toward the margin it is sensibly com- 
 pressed. Strife of undulating lines, in number about twenty, but in- 
 definite. Without a yoke (deltidium) or canal to the dorsal (ventral) 
 valve. In the complete state no transverse furrows have been 
 observed, but deprived of the epidermis (outer shelly layer) the radiating 
 striae are wanting, and the shell appears concentrically striulate. The 
 true structure of the hinge is not rightly explored, but, on account of the 
 external aspect, and its place in the most ancient strata, the species is 
 suspected to belong to the genus A trypa." 
 
 Earljf Leopold von Buch, in the work above cited, presents us with another 
 
 this species, view of this species, and from his impressions, of its form and relations 
 
 referred. it doubtfully to the genus Spiri/er. His account is as follows : — 
 
 " Both shells are slightly elevated ; both, however, have a slightly 
 depressed (hollow ?) in the middle opposite each other. The mar- 
 gin it square-oval, with sides sloping away, and slightly bent down at 
 the back. The hinge of the ventral (dorsal) shell is straight ; in the 
 dorsal (ventral) valve on the contrary, the edges of the hinge are bent 
 into a very blunt angle. This is the only way by which one can dis- 
 tinguish the valves from each other, for the area, which in itself is very 
 small, lies always on the under edge. The greatest width is in the 
 middle of the length (transverse diameter). From 8 to 10 radiating 
 lines go from the middle point (umbo) out, and increase at the border to 
 form 18 to 20 lines. Very fine crowded lines of growth cross these and 
 form a very pretty pattern. Length to the width as 100 to 131. 
 
 This little mussel is crowded together in enormous numbers. They 
 build alone the alum-sbales of Andrarum in Scbona. Indeed, Dalman 
 says that such beds occur throughout the whole of West Gbttland, and 
 also in several other provinces of Sweden." 
 
 Of this species Salter gives the following description referring it to the 
 genus Orthis : — 
 
 *WahIenberg Petr. Tell. Suec. p. 66. 
 
215 
 
 " A well marked and very pi'etty species, and the earliest known in Salter's 
 British rocks. It is hardly ever more than one third of an inch wide, 
 and most specimens are not more than half of that size. The length is 
 less than the breadth in proportion as seven to nine. Our figures repre- 
 sent the shell as distorted in various positions, but the above is about 
 the average measurement. Both valves are somewhat convex, but the 
 dorsal valve has a broad central depression of a triangular shape, bounded 
 by two rather prominent ribs, out of the ten or twelve strong ones that 
 radiate from the beak, and the sinus is occupied by two sub-central and 
 very distinct ones. The lateral ribs are strongly interlined by others 
 half way up, the intervening ribs becoming as strong as the primary ones, 
 and these again by smaller and shorter ones in the intervals. All are 
 crossed by strong, and interrupted, but rather wavy ridges of growth, so 
 as to decussate the surface in rather a remarkable way. The other valve 
 is alike in sculpture, but has a rather prominent beak. The number of 
 ribs varies greatly, but not in a way to make us believe we have more 
 than one species. Sufficient differences are not seen in the Scandinavian 
 specimens to warrant us in separating these which occur in abundance 
 in the alum slates in limestone layers. 
 
 The teeth diverge slightly in both valves ; in the dorsal valve they are 
 subparallel, and short, or even curved a little inward, and are not thick- 
 ened ; while the cardinal process between them is a mere liae or thin 
 edge, which extends as far down as the length of the short lateral teethi 
 but is often very obscure, and sometimes seems to be altogether absent. 
 
 There is little doubt that this is Dalman's species from Egeberg, 
 though the specimens we have from thence have less prominent ribs, and 
 a generally smoother appearance." 
 
 If the reader will compare together these several descriptions of this 
 species by the above writers, he will be surprised at the diversity they 
 exhibit. This diversity, it appears to the wiiter, is due partly to the 
 imperfection of the descriptions of the early writers, but chiefly to the 
 remarkable variability of the species. 
 
 Wahlenberg takes no notice of the difference between the dorsal and 
 ventral valves, for he ascribes to them an equal convexity, and say that 
 the two valves occur together ; but Dr Lindstrom intimates that they 
 have never been found united, and from specimens which he has kindly 
 sent me, it is clear that the Swedish variety has the usual sulcus in the 
 dorsal valve, though in some cases only faintly marked. In the typical 
 form of this species the cardinal area is short and the beak quite low ; and 
 as the convexity of the two valves does nob differ greatly, this appears to 
 be the form which Wahlenberg had in view when describing the species. 
 
Sculpture of 
 the surface. 
 
 216 
 
 Dalman's description on the other hand, applies best to a variety atrypo- 
 ides. He, like Wahlenberg, appears to describe only the ventral valve. 
 
 Leopold von Buch, while recognizing the distinctness of the two valves, 
 ascribes a sulcus to the ventral valve which apparently has not been 
 observed by any other writer. With this exception, his description 
 applies to the type of the species ; that is, the evenly lenticular form 
 with a short hinge line. The extreme thinness of the shell fully, bears 
 out Dalman's remarks on this point, and is associated with inconspicuous 
 hinge teeth and dental plates. The internal markings of the shell pro- 
 duced by the attachment of the muscles and the ovarian spaces are only 
 faintly indicated and often quite undiscernable. 
 
 Sculpture. — There is a wide variation in this respect in examples of 
 different ages, and in the different varieties. As a rule the young shells, 
 especially the ventral valves, are smooth, with only slightly marked 
 diverging ridges. In the Acadian examples of this species the sculpturing 
 is always more distinct on the dorsal than on the ventral valve ; this I 
 find is also the case in the Swedish examples, for which I am indebted to 
 Dr Lindstrom. As the shells grew larger the ribs became more distinct ; 
 and also more numerous by the intercalation of new ribs towards the 
 margin. L. von Buch gives 18 to 20 as the full number of ribs in the 
 adult. This is the usual number in the St. John examples, though a few 
 show as many as 30 ribs. 
 
 Size. — The largest example of this species observed at St. John is 8 
 mm. long and 11 broad; but Brogger mentions that an example from 
 Vestfossen was 15"5 x 12'5. Dr Lindstrom has not seen any so large. A 
 medium sized shell of 5 x 6 mm. is by far the most common in rocks of 
 Eastern Canada. 
 
 Horizon and Locality. — This species is found in limestone lentiles 
 enclosed in the black shales of Division C. 3 a at Germain street, St. John 
 (also in similar shales of C. 3 h, on King Street, and elsewhere) occurring 
 together as in Sweden, in great numbers and of all sizes. 
 
 I have not observed the Cape Breton examples to vary from the above 
 descriptions. In that island the fossil has been found at the localities 
 named below. 
 
 Horizon and locality. — At McNeil brook, east of Mira river in Band 
 C. 3 6 ; at Gillis Brook, on East Bay and at McLeod brook, Boisdale, 
 probably in the same assise, though possibly in Assise C. 3 c. 
 
 Varieties. PI. XVII., figs. 2 a-c, 3 a and h and 4 a and h. 
 
 Varieties. Among the forms found at St. John are three which also may be looked 
 
 for in Cape Breton, viz. : lyncioides, with strong radiating ribs, especially 
 
217 
 
 in the later larval stages ; atrypoides, narrow with prominent umbo to 
 the ventral and deep sulcus to the dorsal valve ; and strophomenoides, 
 with flat, smooth valves and long hinge-line. The two first mentioned forms 
 are from the Peltura fauna (C. 36), and the last from the Parabolina Zone 
 (0. 3a}. 
 
 MOLLUSCA. 
 
 MoDiOLOPSis (?) cf. M. SoLvKNSis, Hicks. 
 
 Bull. Nat. Hist. Soc. of N. Brunswick, vol. iv., p. 408. 
 
 Long-ovate, elevated toward the umbo and carrying its fullness towards Modiolopsis 
 the lower posterior end of the valves. 
 
 The umbo is near the anterior end, and there is a small, transversely 
 elongated scar just in front of it. 
 
 Sculptiire. — The bad condition of the fossils leaves this doubtful for 
 most of the surface, but there are faint concentric striations toward the 
 lower margin and the posterior end. Only two examples known. 
 
 Size. — Length 4J mm. ; width 2 J mm. 
 
 Horizon and locality. — In the fine gray shale of Assise C. 3 c^ at 
 McLeod brook, Boisdale, N.S. 
 
 This species resembles that above cited of Hicks, but lacks the strong 
 ridge extending backward from the umbo. It is also only half of its 
 length. 
 
 BELLEROPHON, Montf. 
 Bbllerophon insula, pi. XVIII, fig. 3. 
 
 Bull. Nat. Hist., Soc, of N. Brunswick, p. 408, pi. xviii, fig. 3. 
 
 A small thin species, having about three whorls, of which the outer is Bellerophon 
 enlarged and more than twice the height of the others ; it is emarginate inf^"!*- 
 on the ventral side, and shows no keel ; it has from two to three concen- 
 tric growth ridges in the outer half of the last whorl. 
 
 Sculptivre. — The outer whorl shows a very fine concentric striation, 
 visible only with a strong lens. 
 
 Size. — Height across the whorls, 7 mm. ; width across the shell from 
 the emargination of the aperture at the ventral side, to the dorsum oppo- 
 site, 4 mm. ; width across the aperture from ventral to dorsal, 4 J mm. 
 
 Horizon and locality. — In the gray shale of Assise C. 3 c^ at McLeod 
 brook, Boisdale, N.S. 
 
 Dr. Henry Hicks' species {£. Ramsayensis), which is about the size of 
 this one, may be con-specific with it, but the Welsh specimens are too 
 
218 
 
 much distorted to be used for satisfactory comparison, and his description 
 is brief.* 
 
 Compared. Prof. |W. C. Brogger figures a species (Bellerophon Norvegicus), from a 
 
 corresponding horizon in Norway. t It is a little smaller, the outer whorl 
 expands more rapidly and is free for half of its length ; it is not deeply 
 notched like our species ; though differing in these respects, it has a 
 striation similar to the Canadian species, only in place of being sharply 
 curved back at the dorsum, the striae curve forward in crossing that line. 
 
 Bellerophon Bretonensis. PI. xviii, 4 a-d. 
 
 Bull. Nat. Hist. Soc. of N. Brunswick, vol. iv, p. 409, pi. xviii, figs. 4 Or-d. 
 
 Bellerophon Shell of about two or more whorls, the outer whorl large and moder- 
 
 re onensis. g^(.g|y expanded. Orifice somewhat enlarged and strongly emarginate on 
 
 the dorsal side by a sharp V-shaped sinus. Sides of the opening strongly 
 
 arched upward between the dorsal and ventral sides. No distinct keel. 
 
 Sculpture. — The surface is diversified with numerous rounded ridges 
 concentric to the umbo, with flat spaces between ; there is a sharp, nar- 
 row furrow along the crest of each ridge ; the ridges near the orifice are 
 sharper and more crowded than farther back on the whorl ; here there 
 are about three in the space of 2 mm., but towards the mouth about four. 
 The fine sculpturing of the surface appears to be a minute granulation. 
 
 Size. — Length from the inner .part of the last whorl to the lateral edge 
 of the lip, 20 mm. Width across the shell from the dorsum to the inner 
 part of the last whorl, 12 mm. 
 
 Horizon and locality. — Fine gray shale of Assise C, 3 c^ at McLeod 
 brook, Boisdale, N.S. 
 
 Compared. The characters of this shell are obscured by fl.attening in the shale. The 
 
 umbo appears to be excentric, and it resembles B. CElerti, Bergeron, of 
 the Lower Ordovician of the Montagne Noire in Southern France, J but 
 has fewer whorls. Similarly to that species, the ridges on the shell are 
 more distant from each other on the upper part of the main whorl than 
 towards the aperture. I could not detect any flattened ridge along the 
 keel of the dorsum. 
 
 This shell is distinct from B. ar/onensis, Salter, by the sharp angula- 
 tion at the dorsal line, and the striae that cross it are angulated, not arched. 
 
 * Quart. Jour. Geol. Soc, London, vol. xxix, No. 113, p. .oO, pi. iii, figs. 30-32. 
 t Memoir cited, p. 5.S, pi. x, figs. 15, 15o., 156. 
 
 JEtude geologique du Massif Anoien sitn^ au sud du Plateau Central, J. Bergeron, 
 Paris, 1889, p. 343, pi. iv, figs. 10 and 11. 
 
219 
 
 Bellerophon semisculptds. pi. XV^III, fig. 5. 
 
 Bull. Nat. Hist. Soc. of N. Brunswick, voL iv, p. 410, pi. xviii, fig. 5. 
 
 Only the last whorl khown. This is free from the inner part of the Bellerophon 
 coil. The proximal part is smooth with faint concentric undulations of 
 growth. 
 
 The lines of growth arch backward toward both ventral and dorsal 
 side, and at the dorsum there is an elevated flattened keel, separated from 
 the lateral slopes by a slight furrow ; the strise that run backwards to 
 this keel traverse it at right angles. 
 
 Sculpture. — The outer two-thirds of the whorl is marked by sharp- 
 edged, concentric ridges of growth ; at first there are about four in the 
 space of a millimetre, then they become more distant with flattened spaces 
 between, and toward the orifice of the shell there are about two ridges in 
 the same space. Between the ridges, and on the smooth part of the 
 whorl, the surface of the shell is minutely granulated. 
 
 Size. — Only one example is known, which is 7 mm. across from the 
 back of the whorl to the mouth, and 6 mm. across from the ventral side 
 of the mouth to the dorsal keel. 
 
 Horizon and locality . — In fine gray shale of Assise C. 3 c^ at McLeod 
 brook, Boisdale, N.S. 
 
 This species rssembles B. hippopus, Salter, of the Arenig horizon in Compared. 
 Wales. It differs in its smaller size and in the very regular ridges of 
 growth, there being no alteration of weak and strong ridges. From B. 
 ar/bnensis, of the same author, it differs in the raised keel in place of a 
 depressed band along the dorsum. 
 
 OSTRACODA. 
 
 Beyrichia triceps, n. sp. Plate xvi, figs. 4 a to c. 
 
 Form sub-semicircular, about one-third longer than wide. Hinge line Beyrichia 
 straight, nearly the length of the valve ; valve somewhat oblique, the '*^' 
 anterior marginal slope being straightened, posterior cardinal slope short, 
 anterior wanting ; valve slightly pointed at the ventral edge. Surface 
 raised in three tubercles toward the hinge line ; of these the anterior 
 becomes a high narrow ridge, close to the anterior margin, and about 
 half as long as the width of the valve ; it is highest in the middle of its 
 length, where it is crowned by a small (ocular V) tubercle ; one example 
 shows several colored spots (in place of one, which is usual) on the mould, 
 along this ridge. There is a narrow marginal fold around the edge of 
 the valve, except at the hinge. 
 
Comparison 
 with other 
 
 220 
 
 Sculpture. — The surface of the test is coarsely granular, but smoother 
 toward the summit of the ridges and toward the hinge. 
 
 Size. — Length 2 mm. ; width li mm. ; depth about ^ mm. for each 
 valve. 
 
 Horizon and locality. — The cal"iferous gray flags of Band C. 2 h, at 
 McLean brook, near Mira River, N. 8. Common. 
 
 This species is a link between Beyrichona and Beyriehia ; the general 
 form and moulding of the shell is similar to that of Beyrichona, but the 
 sharp, high ridge at the anterior end is different from any species of that 
 f^enus. 
 
 It differs from Beyriehia nana, Brogg. of the *Ceratopyge limestone 
 (Temadoc horizon), in its larger size, broader valves, and in having a 
 higher ocular ridge. From B. costata, Linrs. of the Beyriehia lime- 
 stone (Ordovician)t in its greater width and sharp high ridge near the 
 anterior margin. Prom B. primceva of the Protolenus FaunaJ it differs 
 in its .smaller size and greater width and in having more prominent lobes. 
 
 TRILOBITA. 
 
 Agnostus 
 trisectus, mut, 
 ponepunctus. 
 
 Agnostus teisectus. Salt. mut. ponepunctus. PI. XVII., figs. 8a-c. 
 
 Bull. Nat. Hist. Soc. of N.Brunswick vol. iv., p. 278, pi. v. figs 8a-c. 
 
 This form grows to a larger size than the type as figured by TuUberg, 
 and differs in several respects. The reticulation on the head-shield does 
 not show a net- work near the glabella, but detached irregular furrows ; 
 opposite the posterior half of the glabella the ornamentation is scarcely 
 more than small, sparse, irregular pits. The posterior end of the glabella 
 is wider than that of the European form, and there are lateral lobes 
 near the front of the main lobe. 
 
 In the pygidium there are also differences ; the sculpturing of the side- 
 lobes is scarcely more than shallow, open pits, faintly visible, and there 
 is a small tubercle at the end of the rachis, which overhangs the rachial 
 furrow. Examples of the pygidium showing the inner surface, have as 
 many as nine paired pits along the inner furrow of the posterior lobe of 
 the rachis, showing that that lobe is composed of numerous somites. 
 
 Size. — The shields of this mutation of A. trisectus attain a length of 8 
 mm. 
 
 * Die Silurisoh. Etagen, 2 und 3, p. 55, tab. xil, tig , 15. 
 
 tKongl. Svensk vetenskapsakad. Handl. bd. 8 no. 2, p. 85, tafl., figs. 67, 68. 
 
 J Trans. Roy. Soc. Can., 2 ser., vol. iv, see. IV, p. 133, pi. i, figs. 2 a-c. 
 
221 
 
 Horizon ond locality. — In bituminous limestone bed of the Band C. 36, 
 atMcAdam shore, Escasonie, Cape Breton. 
 
 A singular condition of preservation of the lest of this species is the 
 rarity of remains of the thorax. Among two dozen heads and three dozen 
 tails of this species, only one joint of the thorax was observed. 
 
 Larval characters. — The reticulation or furrowing of the cheeks, which Larval 
 is so obvious a character of adult head-shields, becomes less and less pro- 
 nounced in the small heads, and disappear in minute ones. Faint furrows 
 are impressed at the sides of the main lobe of the glabella, opposite the 
 median tubercle, showing a somite here to which this tubercle belongs ; 
 the examples are 1 J mm. long, in which this is apparent. 
 
 A pygidium ^ mm. long, shows a comparatively short rachis of two 
 segments of whicji the anterior is dominated by a low ridge-like tubercle; 
 no true anterior lobe, such as is found in adult shields, can be detected 
 at this stage. The posterior lobe, by faint tubercles at the sides is shown 
 to be composed of at least two somites, yet the trisected condition of the 
 rachis is already apparent. 
 
 Mut. GERMANUS. 
 
 Bull. Nat. Hist. See. of N. Brunswick vol. iv. p. 279. 
 
 This interesting form has many points of resemblance to A. frisectus, Muta,tion 
 and is of nearly the same size, but yet is not trisected on the posterior B^*^™*""^- 
 lobe of the rachis of the pygidium. This form and mut. ponepunctus 
 sometimes occur scattered over the same surface of rock, but more fre- 
 quently are distributed on different surfaces. The smoothness of the slopes 
 of the shields and the absence of trisection in the posterior lobe might 
 lead one to think it a different species from mut. ponepunctus and from 
 A. trisectus, type, but the tubercle at the end of the rachis of the pygidi- 
 um, peculiar so far as the author knows to the Cape Breton forms, leads 
 one to think they belong to one species. 
 
 Horizon and locality. — In Band (C. 36) at Escasonie shore. East bay, 
 
 N.S. 
 
 Since writing the above I have received a letter from Prof. J. E. Marr, Cpmpared 
 of St. John's College, Cambridge, who has had the examples of A. trisec- ^ ^^' 
 tus, in the Woodwardian Museum examined, and also those of the Geolo- 
 gical Museum in Jermyn street, London ; on none of these is there any 
 trace of a tubercle at the extremity of the mid-lobe of the pygidium. 
 This indicates a closer relationship between the two Canadian forms than 
 is borne by either of them to th(^ type, though the apparent difference 
 
The two 
 Canadian 
 varieties 
 contrasted. 
 
 222 
 
 seems to be greater ; it appears also to show that the American mutations 
 arose independently of the typical forms, from the Longifront phylum. 
 The indication is similar to that given by the development of Anomocare 
 stenotoides from the Glenoid phylumj i. e., a tendency to the independent 
 development of similar forms at particular stages in geological history.* 
 
 The differences of mut. germanus from A. trisectus-ponepunctus, are 
 the following. The head-shield is more strongly arched, stiffer and 
 smoother; the pygidium is not trisected on the posterior lobe of the rachis, 
 thought faint furrows may sometimes be traced on one side or the other. 
 It differs from tlie European type of trisectus, in that the median lobe tra- 
 verses the middle part of the two anterior segments, thus interrupting 
 the dividing furrow between these segments, and it differs also in its 
 smooth, stiff shields. 
 
 This mutation shows a considerable resemblance to A. princeps, Salt. | 
 But Salter is emphatic in stating that there are no marginal spine (never- 
 theless two of these figures show such spines, (perhaps there are two 
 species included under A. princeps). The figure of Salter's species which 
 comes nearest ours is 16 of plate 5, but in that the tubercle on the gla- 
 bella i-* represented as elongated and resting on the middle of the main 
 lobe, while in the Cape Breton form it belongs entirely to the anterior 
 segment or somite of the main lobe. 
 
 Agnostus, cf. CYCLOPYGE, TuUberg. 
 
 cf. Agnostus cyclopyge, TuUb. Sverig. Geol. Unders6k, Ser. C. No. 42, p. 
 26, table ii, fig. 15c. 
 
 Agnostus cf. A single pygidium that corresponds to Tullberg's figure of this species 
 
 eye opyge. ^^^ found in association with the other trilobites of the Peltura Fauna 
 
 at Escasonie. The posterior lobe of the rachis is quite obliterated, not 
 
 even showing the little grooves on each side of the front of this lobe, 
 
 shown in Tullberg's figure. 
 
 (Size.— The example is small, not more than two-thirds of the length 
 of the typical form. 
 
 Horizon and locality. — In a thin limestone of Band C 36 at Escasonie 
 shore East bay, N.S. 
 
 * See. Trans. Roy. Soc. Can. vol. iv, sec. iv, pp. 140-148. 
 
 t Mem. Geol. Surv. G. Britain Jvol. iii, p. 488, pi. 4 figs 2 and 11a, and pi. 5, figs. la. 
 and b. 
 
223 
 
 -Agnostus, cf. var. declivis. 
 
 of. Agnostus Acadicus, var. declivis. Trans. Roy. 
 
 Soc. Can. vol. iii, sec. iv, p. 70, pi. vii, figs. 6 a and b. 
 
 A small species of the Limbatus section of the genus Agnostus, occurs Agnostus cf. 
 at the Peltura locality on McNeil brook. It is too imperfectly preserved dechvis. 
 for exact determination, but it carries this type of Agnostus into the 
 Upper Cambrian as A. bisectus does the B. concinnus type. 
 
 Occurring in dark grey shale with Pdtura scarabeoides, Gtenopyge 
 (lobata ?) and Agnostus (trisectus ?) McNeil brook, Mira river in Band 
 C. 36. 
 
 PARABOLINA, Salt. 
 Parabolina Dawsoni. pi. XVIT, figs. 6a-/l 
 
 Bull. Nat. Hist. Soc. of N. Brunswick., vol. iv, p. 282, pi. v, figs. %ar-f. 
 
 The middle piece of the head-shield is sub-trapezoidal in form, is strongly p, „i,oi„„ 
 arche I in front, where there is a narrow but prominent marginal fold, Dawsoni. 
 and has triangular projecting posterior angles. The glabella is cylindro- 
 conical in outline, and is as broad as its length and half of the width of 
 the occipital ring ; it is as broad opposite the first furrow as at the occi- 
 pital ring, and thence narrows more rapidly to the front, which is strongly 
 arched ; the front margin is correspondingly arched, and the intervening 
 area of the fixed cheek is therefore of nearly even breadth around the 
 front of the glabella ; the width of this area on the median line is two- 
 ninths of the length of the glabella. The glabella is marked by three 
 pairs of furrows, nearly equidistant, and having the inner extremities 
 . turned backward ; the inner half of the posterior furrow is more evenly 
 impressed, and the anterior furrow is more distinct in the outer half, 
 which is at the anterior corner of the glabella. The occipital ring is of 
 nearly even breath, has a tubercle on the axial line, and has a triangular 
 lobe at each end on the anterior side, due to a faint furrow that crosses 
 the ring diagonally. The fixed cheek is triangular, and at the front of the 
 eyelobe as wide only as two-thirds of the space between the glabelbir fur- 
 rows ; the eyelobe is opposite the space between the second and third 
 furrow of the glabella, aud there is a short ocular fillet extending diago- 
 nally out to it from the anterior corner of the glabella. The posterior 
 marginal furrow and fold are distinctly marked. 
 
 The movable cheek is more strongly arched in front than behind, and Description of 
 like the middle piece of the head-shield, has a sharp, narrow marginal fold ; I'arts. 
 the area of the cheek is somewhat wider in front than behind, and the 
 proportion in length of the three cords of the facial suture is 1, 1, 2\. 
 
224 
 
 Sculpture. 
 
 Compared 
 with other 
 species. 
 
 There is a narrow, sharp genal spine, of unknown length, projecting back- 
 wrard from the outer angle of the cheek. 
 
 The thorax has narrow rings with narrow pleurae, having sharp back- 
 ward-curved points. The thoracic rings have triangular lobes at the 
 outer ends and a median tubercle, like the occipital ring. The pleurse 
 have a sharp, oblique furrow, extending to the geniculation. 
 
 A hypostome supposed to belong to this species has a large, oval anterior 
 lobe, narrower behind ; an upturned margin borders it at the sides, but 
 at the back is broken away. 
 
 The pygidium has two well marked rings to the rachis, each sur- 
 mounted by a tubercle, and a posterior lobe which is obscurely divided 
 into two somites. The side lobes have two faintly marked ribs with 
 diagonal grooves, and the borders of the side lobes are flattened. A 
 small backward, outward projecting spine is placed at the anterior corner, 
 on each side. 
 
 Sculpture. — The area in front of the glabella is ornamented with 
 forking and anastomosing raised lines, radiating toward the anterior 
 margin. The glabella appears smooth, but under a strong lens is seen to 
 be minutely punctate, or even obscurely reticulate with raised lines. The 
 movable cheek, like the area in front of the glabella, is ornamented with 
 distinct raised lines, giving a reticulate surface ; toward the marginal 
 fold these lines are forked and directed outwards. 
 
 The reticulation of raised lines is more distinct on the interior than on 
 the exterior surface of the te.st. A similar but faint reticulation is visible 
 on the front half of the fixed cheek. The surface of the glabella, seeming 
 smooth to the naked eye, when viewed with a lens appears to the faintly 
 marked with scattered pits or depressions. The front and lateral marginal 
 fold of the head-shield, when viewed with a strong lens, is seen to be 
 minutely striate lengthwise of the fold. 
 
 Size. — The head-shield figured is not the full size of this species, for 
 some pleurse show that it grows to a size one-quarter longer. 
 
 Horizon and locality. — In limestone of Band C. 36 at Escasonie shore, 
 East bay. N.S. 
 
 This species is closely allied to P. acanthura, Ang.,* from which it 
 differs in the following respects : The area in front of the glabella is 
 wider and more strongly arched, and the fixed cheek is more pointed at 
 the posterior outer angle. In the free cheek the rim is more strongly 
 arched in front, and has less width behind. The joints of the thorax 
 
 *Pal8eontol. Soand., p. 49, pi. xxvi, fig. 9. Also Om Aoerooare, Moberg & MoUer, 
 Stockholm, 1898, p. 239' tafl. 12, figs, la and 4a. 
 
225 
 
 have tubercles, or, in some cases, spines on the rings. The pygidium has 
 a median tubercle on each of the first two joints, and the marginal spines, 
 of which only one pair is known, are directed outward rather than back- 
 ward. In other respects the two species, in so far as comparisons can 
 be made with the imperfect material obtained, are much alike. 
 
 This species is distinguished from Protopdtura acanthura, var. tetra- 
 canthura,* by the broad, area in front of the glabella, and by its broader 
 pygidium with fewer joints. From Parabolina heres, var. lata,i it 
 differs in the arched anterior border fold, and narrow fixed cheek. From 
 P. here', as depicted by Brogger, it difiers in its shorter pygidium of ■ 
 fewer joints, j From P. acanthura, as figured by the same author, in 
 its more quadrate glabella, and in the tubercles on the rings of the rachis 
 of the pygidium.§ From P. heres, as shown by Moberg and MoUer, in 
 the absence of strong reticulation on the surface of the fixed cheek, and 
 the fewer joints in the pygidium. || From P. acanthura, as figured by 
 these authors, in the arched front of the head-shield, and in the presence 
 of tubercles on the rachis of the pygidium.** 
 
 From Paraholinella Plantii, Salter, as figured by F. R. C. Reed, it 
 differs in its arched front margin, broader glabella, differing glabellar 
 furrows, and in possessing pygidial spines.ft 
 
 If it were not for the pair of marginal spines at the front corner of 
 the pygidium, this species, from the flattened side lobes of the pygidium 
 and other features, would fall under Brogger's sub-genus Paraholinella. | J 
 
 PaRABOLINELLA ? QUADEATA, PI. XVIII, fig. 7. 
 
 Bull. Nat. Hist. Soc. of New Brunswick, vol. iv, p. 411, pi. xviii, fig. 7. 
 Middle piece of the head shield subtrapezoidal in outline. Anterior Paraboli- 
 marginal fold narrow ; width of the front area of the cheek, one-fourth drata. *' 
 of the length of the glabella. Glabella quadrate in front, and as wide 
 there as its length, but considerably narrower at the posterior furrow. 
 Posterior and second furrow directed backward, and deeply impressed in 
 the outer third, but not reaching the margin of the glabella. Eyelobe 
 slightly elevated, extending opposite the two anterior furrows of the gla- 
 
 * Trans. Koy. Soc. Can., vol. ix, sec. iv, p. 53, pi. xiii, figs. 8a-e. 
 
 tTrans. Roy. Soc. Can., vol. ix, p. 51, pi. xiii, figs. 6a-/. 
 
 t Die Silurish. Etagen 2 und 3, p. 101, tab. i. fig. 13d. 
 
 § Idem, p. 106, tab. 14, 14c. 
 
 11 Om. Acerocarezonen, Stockholm, 1898, p. 267, tafl. 12, figs. 8a, 11a. 
 
 ** Idem, p. 259, tafl. 12, figs, la and 4a. 
 
 tt Geol. Mag. New ser. dec. iv, vol. vii, p. 303, fig. 1. 
 
 it Ibid new ser. dec. iv, vol. iii, p. 303. 
 
 15 — C K. 
 
226 
 
 Compared 
 ■Hdth other 
 species. 
 
 biBlla ; ocular fillet broad and indistinct. Fixed cheek triangular, about 
 as wide behind as the length of the dorsal suture behind the eyelobe. The 
 posterior marginal furrow is faintly marked. The dorsal suture arches 
 outward in front of the eyelobe, and behind it goes direct backward and 
 outward to the posterior margin, and in that part is nearly half as long 
 again as the cord of the eyelobe and anterior part of the suture together. 
 
 The pleurae are long and narrow, and have a sharp, deep furrow, which 
 is nearest the posterior margin ; they are sharply bent, and pointed at 
 the ends. The ring is pushed up in the middle into a pseudo-tubercle, 
 such as is common on the occipital ring of species of this genus. 
 
 Sculpture. — A row of faintly marked tubercle-like swellings are found 
 along the bottom of the anterior marginal furrow. The middle piece of 
 the head-shield in all its parts appears smooth, except for a minute punc- 
 tation. 
 
 Size. — Middle piece of the head-shield 25 mm. long. It is 25 mm. wide 
 at the anterior and about 40 at the posterior end. 
 
 Horizon and locality. — In gray shale of Assise C. 3 c^, at McLeod 
 brook, Boisdale, N.S. 
 
 This species is near Paraholinella limitis of Brogger. It difiers in 
 its longer and more quadrate glabella. The fixed cheek also is longer and 
 the eyelobe less prominent. Apparently also it is a larger species. 
 
 From P. rugosa of the same author it is distinguished by its more quad- 
 rate glabella and by a different arrangement of the glabellar furrows. It 
 resembles this species in the possession of a comparatively wide area in 
 front of the glabella. The glabella so wide in front (one-seventh wider 
 than at the posterior lobe), recalls that of Ceratopyge forficula, Sars., of 
 a similar horizon in Sweden.* 
 
 Parabolinella 
 cf. limitis. 
 
 PaEABOLINELLA (?) cf. LIMITIS, Brog. 
 
 The middle piece of the head-shield of a young individual which, by its 
 form, agrees with the figures of this species, given by Professor Br6gger,f 
 was found in these beds. Only one example was met with. The size of 
 the shield is 2^ x 4 -I- mm. The interior of the shield shows three pairs 
 of furrows, a strong ocular fillet, and a well-marked eyelobe. 
 
 * Die Silureschen Etagen 2 und 3, p. 14, tab. 3, fig. 3. 
 t Ibid p. 102, tab. iii, figs. 2 and 4. 
 
227 
 
 Sph^rophthalmus Fletcheri. Plate xvii, figs. la-f. 
 
 Bull. Nat. Hist. Soc. of New Brunswick, vol. iv, p. 280, pi. v, figs. 7 a-f. 
 General outline of the -middle -piece of the head shield, square, with a Sphaeroph- 
 large, nearly cylindrical, glabella, which in front overhangs the narrow yietoheri. 
 marginal fold. The glabella has a width two-thirds of the length of the 
 glabella and occipital ring together. A strong furrow divides off the 
 third of the glabella. The occipital ring is narrower than this lobe of the 
 posterior glabella, and bears a tubercle at the middle. 
 
 The fixed cheek is much drawn in behind and then arches downward 
 and outward to the posterior margin. The front of the cheek is tumid 
 ■and traversed by an ocular fillet directed diagonally backward. 
 
 To the movable cheek is attached the large globular eye, placed near the 
 back of the cheek, the cheek is prolonged outward into a flat spine of 
 abnormal size ; this spine is as wide in the front quarter as the 
 cheek itself, and curves backward in a regular arch at first, but toward 
 the extremity becomes nearly straight. Of the two ribs which traverse 
 ■it, one is an extension of the posterior marginal fold, and the other is a 
 prolongation of the elevated middle part of the cheek. The flattened area Parts of this 
 ■on each side of the spine is a special expansion of the anterior and 
 .posterior marginal folds, and towards the tip of the spine, narrows more 
 rapidly than the area occupied by the ribs ; of the flat areas, the outer 
 is hollowed on the upper side, and the inner one somewhat convex on 
 that side, especially toward the base of the spine. 
 
 A young hypostome, imperfect at the front, which may belong to this 
 «pecies, has a narrow, elevated obconical anterior lobe extending two- 
 thirds of its length ; and an encircling, more depressed posterior lobe, 
 occupying the rest of the hypostome ; both lobes are convex, and no border 
 fold is visible. 
 
 The pygidium of this species is broadly triangular, and has a strong 
 oTjconical rachis of three segments, the third nearly as long as the two 
 anterior. These latter have each an obscure lobe at each side. The side 
 lobes are narrow triangles, with a tubercle at each anterior outer 
 corner. There is a distinct but narrow border fold at the sides and 
 posterior end of the pygidium. 
 
 Sculpture. — This is exceedingly minute and appears to consist of very 
 fine granulations with a smooth, shining surface on the front lobe of the 
 glabella; this part of the glabella shows occasional scattered small 
 tubercles. 
 
 15J — c. R. 
 
228 
 
 Size. — Length of the middle piece of the head shield 3 mm. width, 5 
 mm. Length of the movable cheek, 3 mm. ; width, exclusive of the genal 
 spine, 2J- mm. Width of the genal spine, 2J mm. ■; length, 25 mm. Length 
 of the pygidium, 1|- mm. ; width, 2 mm. Length of a young hypostome, 
 IJ mm. ; width, 1 mm. 
 
 Locality and horizon. — Limestone bed in 0. 36 at McAdam's shore, 
 
 Compared 
 
 with other . /-. t. t^t i-i 
 
 species. Escasonie, Cape Breton, N.8 
 
 This form is distinguished from the mutation Canadensis of S. alatus, 
 found in the upper Cambrian shales at St. John,* and from the type of 
 that species, by its long, flat and very wide, falcate genal spine. It 
 agrees nearly with a spine and free cheek figured by Linnarsson, but 
 not referred to any species. The cheek portion of S. Fletcheri is very 
 small compared with the spine, which is stiffened by the two sharp 
 ridges that run along the middle ; these ridges occupy about a third of 
 the width of the spine, the rest being flat. 
 
 The pygidium of this species difiers from that of the type of ^S'. alatus 
 as figured by Linnarsson in the possession of narrow side lobes (about as 
 wide as the marginal fold) ; that author's figure gives no side lobes, the 
 marginal fold being in contact with the rachis.f 
 
 For numbers, this is the dominant species in the trilobite bed at McAdam 
 shore, as will be seen by the following proportion of forms found on five 
 square inches of surface of one of the layers. 
 
 Comparative 
 abundance. 
 
 Sphserophthalmus Fletcheri 30 heads. 24 cheeks. 
 
 Agostus trisectus, chiefly the mut. ponepunctus 9 " 1 pi 6 pyg. 
 
 Ctenopyge pecten 8 " 3 cheeks. 
 
 Peltura scarabeoides 1 " 4 pi. 1 pyg. 
 
 Parabolina Dawsoni 1 " 
 
 All the heads of Sphserophthalmus were not counted ; several were so 
 small that the generic characters were not well shown. 
 
 Sph^rophthalmus alatus, Boeck. 
 
 Sphseroph- 
 thalmus 
 alatus. 
 
 1838. Trilohites alatus, Boeck, Gsea. Norveg., p. 143. 
 1848. Olenus humilis, Phill. Mem. Geol. Surv., vol. ii., pt. i, p. 55, figs. 
 4, 5, 6 and p. 347. 
 
 * Trans. Eoy. Soo. Can. vol. xi, sec. iv, p. 107, pi. xvii, figs. 11a and 6, 12o and 6. 
 t Geol. forening, i Stockholm Forhandl, 1880 No. 60 Bd. No. 4, p. 2 fig. 14. 
 
229 
 
 1854. Sphcerophthalmus alatus, Ang. Pal. Scand., p. 49, t. xxvi., fig. 9. 
 1866. Olenus (Sphcerophthalmus) humilis, Sale, Mem. Geol. Surv. G. 
 
 Brifc., vol. iii, p. 302, t. v., fig. 12. 
 1880. Sphcerophthalmus alatus, Linrs. Geol. forening i Stockholm For- 
 
 handl, No. 60 ; Bd. v., No. 4, p. 7, t. 1, fig. 6-10. 
 1893. S. alatus var. Canadensis, Trans. Roy. Soc. Can., vol. xi., p. 107, 
 
 pi. 17, figs. 11a and b. 
 
 This common and widespread species of the Upper Cambrian has been 
 found at two points in the eastern provinces of Canada, viz., at St. John, 
 N.B., and at McNeill brook, near the Mira river in Cape Breton. It is 
 found both in the dark gray slates at the latter locality and in some of 
 the thin limestone bands found in these slates. 
 
 The Cape Breton material is not sufficient to determine whether the 
 variety is represented there, or the original form. 
 
 CTENOPYGE, Linrs. 1880. 
 Ctenopyge pecten, Salter. PL XVII., Figs. 5 a and b. 
 
 1864. Olenus {Sphcerophthalmus) pecten. Salt. Mem. Geol. Surv. G. Ctenopyge 
 Brit., Dec. xi., p. 9, t. viii., fig. 11, 13. P^"'^"' 
 
 1866. Olenus (Sphcerophthalmus) Jlagifiifer, Salt. Mem. Geol. Surv. G. 
 Brit., vol. iii, p. 301, t.' 5, figs. 3, 9. 
 
 1866. Olenus (Sphcerophthalmus) alatus, Salt. Loc. cit., p. 302, t. 4., 
 fig. 3, 3a. 
 
 1891. Ctenopyge peeten, Trans. Roy. Soc. Can., vol. ix., p. 58. 
 
 This species, which was only doubtfully recognized by fragments in the 
 limestone lintels of the black slates of Div. C. 3b, at King street, St. 
 John, is clearly present in the corresponding assise in Cape Breton. The 
 peculiar herring-bone-like rachis of its broad pygidium is frequently met 
 with among other fossils of this horizon on the Escasonie shore. Linnar- 
 sson asserts that the segment of the side lobes in this pygidium are quite 
 free from each other, and are entirely analagous to the pleurse of the 
 thorax ; yet the rachis must be strongly cemented, for it is a part not 
 infrequently met with when no other portion of the pygidium can be 
 recognized. This, we may assume, is owing to the fact that the almost 
 free lateral segments have, owing to their slendemess, been broken off- 
 A rough copy of Linnarsson's beautiful figure is reproduced on one of the 
 plates with article PI. xvii., fig. 5 b. 
 
 This species is quite abundantly miagled with Sphcerophthalmus Fletcheri Occurs with 
 
 on surfaces of the bituminous limestone at the Escasonie shore. Most of preceding 
 
 species. 
 
Peltura 
 soarabeoides. 
 
 230 
 
 the full grown examples agree with Salter's indication of the size, but 
 occasional larger head shields are found, that do not appear to differ essen- 
 tially from the type ; these have a middle piece to the head shield that 
 is 3 X 6 mm. measured at the axial line, but 3x7 mm. at the longest part 
 of the fixed cheek. 
 
 All the pygidia seem to have been broken up, and, are rare compared 
 with the head shields ; three or four examples of the comb-like rachial 
 part of the tail shield were seen. 
 
 The young (or a small variety) dififer considerably from the larger ones 
 in the form of the glabella ; this part is proportionately shorter (which 
 for a larval condition is unusual) and the front lobe is rounder and more 
 prominent. 
 
 Horizon and locality. — The limestone layers in the bottom of Band 
 C. 36. at Escasonie shore, East bay N.S. 
 
 PELTUEA SOARABEOIDES, "Wahlenb. 
 
 1821 Untomostracites scarabeoides, Wahlenb. Petrif. Tell. Suec. p. 41 
 
 t. i fig. 4. 
 
 1822 Paradoxides scarabeoides, Brongn. Hist. nat. des crust, foss. p. 34 
 
 t. iii fig. 5. 
 1827 Olenus scarabeoides, Dalm. K. Vet. Akad. Handl 1826, p. 72. 
 1840 Peltoura scarabeoides, Milne-Edw. Hist. nat. des crust, tom. iii, p. 
 
 344. 
 1847 Petura scarabeoides, Corda, Monog. der Bohmisch. Trilobit. p. 127, 
 
 t. vi, fig. 68. 
 1866 Olenus scarabeoides, Salt. Mem. Geol. Surv. G. Brit. vol. iii, p. 301, 
 
 t. 15, figs. 2-5. 
 1886 Peltura scarabeoides, Wahl., Trans. Roy. Soc. Can., vol. iv, p. 147 ; 
 
 vol. viii, p. 126 ; vol. ix, p. 53. 
 
 This characteristic species is that by which the presence of Cambrian 
 rocks was first recognized in Cape Breton. It occurs at McNeill brook, 
 east of Mira river and also at the Escasonie shore, in both cases marking 
 the presence of the Assise C. 3 6. of the St. John terrane. 
 
 Triarthrus 
 BeUi. 
 
 Triarthrus Belli, PI. xviii, fig. 8. 
 
 Bull. Nat. Hist. Soo. of New Brunswick, vol. iv, p. 412, pi. xviii, fig. 8. 
 
 Only the middle piece of the head-shield is known ; this is sub-quad- 
 rate, with narrow cheeks and anterior margin. 
 
231 
 
 There are traces of a very narrow anterior marginal fold, and behind 
 it a narrow convex anterior area of the cheeks. The glabella is quadrate, 
 rounded in front, and bears three pairs of furrows, which are progres- 
 sively less bent backward from the back to the front pair, though the 
 two posterior pairs are already parallel ; the anterior pair are quite faint, 
 and more strongly arched than the others. The glabella is somewhat 
 keeled along the axial line. T^h^ fixed clieek is long and quite narrow, and 
 is separated from the front area by a shallow furrow ; at the eyelobe it 
 is about one-third of the width of the glabella, and at the back about one- 
 half. The eyelobe is long, narrow and obscure. The posterior marginal 
 fold is narrow but prominent. The occipital ring is bent forward at the 
 ends, and has a tubercle on the axial line. 
 
 Sculpture. — This species has a smooth test, but under a small lens 
 shows a somewhat uneven surface. 
 
 Size. — Only one example known ; in this the middle piece of the head 
 is 6 mm. long and 10 mm. wide at the back. Scarce. 
 
 Horizon andlooality. — Fine gray shale of Assise C 3 c^ at McLeod 
 brook, Boisdale, N. S. 
 
 This species is clearly distinct from T. Beckii, Green, by its narrower Compared 
 
 cheek and wider space between the sutures in front. It resembles more ^'^ . °™^'' 
 
 ... species. 
 
 closely T. Angelini, Linrs, but it differs from the type of that species as 
 
 figured by Liiinarrsson in the wider frontal area of the cheeks and its 
 
 convex front margin ; also in possessing three pairs of furrows, &c. 
 
 From the Norwegian form, referred to this species by Brogger, it differs 
 
 in its narrower glabella, rounded front, and in having three pairs of 
 
 furrows, though the third one is faint ; the anterior area of the fixed 
 
 cheek is wider, and is separated from the rest of that cheek by a shallow 
 
 furrow ; it is, however, nearer this form than to any other known to me. 
 
 Billings does not describe T. Fischeri, except by contrast with other 
 species (Upper Ordovician chiefly), but from his figure of that species, the 
 Cape Breton form differs in the posterior marginal fold, which is not 
 turned forward, like T. Fischeri. It also differs from that species in hav- 
 ing an anterior buccal area and in the absence of pits on the front of the 
 glabella.* 
 
 I refer this species to Triarthrus rather than Parabolinella because of 
 the narrow fixed cheeks, the long, backward turned eyelobes and the 
 regular, straight furrows on the glabella. 
 
 ♦Palseoz. Fossils, vol. 1, p. 291, fig. 280. 
 
232 
 
 A young 
 Angelina. 
 
 Angelina 1 sp. ? PI. xviii, fig. 9. 
 Bull. Nat. Hist. Soc. of N. Bruns'k., vol. iv, p. 413, pi. xvm, fig. 9. 
 
 While we have no adult of this genus from the Tremadoc of Cape 
 Breton, there is a young larval shield which seems to agree reasonably 
 well with the characters of this genus by its suture and general outline. 
 Only the head shield has been preserved. This is narrow, as are all its 
 parts. The eyelobes are curved and linear, starting from near the front 
 of the glabella in a heavy ocular fillet, the eyelobes are placed about the 
 middle of the cheek. The movable cheeks have extended spines, and are 
 cut off in front by the curving suture. The glabella is ridged along the 
 middle, and has traces of three pairs of faintly marked furrows. The 
 occipital ring is narrow and weak. 
 
 Sculpture. — The surface appears smooth. 
 
 Size. — Length of this larval headshield, 5 mm. (or to the end of the 
 spines 8 mm.) ; width, 7 mm. 
 
 Horizon and locality. — Gray shale of Assise C 3 c 2 at McLeod brook, 
 Escasonie, N. S. 
 
 Asaphellus 
 Homfrayi, 
 var. 
 
 ASAPHELLUS Callaway. 
 
 Asaphellus Homfrayi, var. PI. XVIII, figs. lOo-e. 
 
 cf. Asaphus Homfrayi, Salt., Mem. Geol. Surv. G.B., vol. iii, p. 311 
 pl. viii, figs. 11-14, 1866. 
 
 Bull. Nat. Hist. Soc. of New Brunswick, vol. iv., p. 413, pl. xviii., figs. lOa-e. 
 Salter's description of Asaphellus Homfrayi is as follows : 
 "Asaphus (Isotelus) long-oval, gently convex, having the head sub- 
 
 angulate in front, and having short [genal] spines. Facial suture within 
 
 the margin. Eyes submedian [near the mid-length of the shield], small. 
 
 Pygidial axis long, somewhat prominent at the apex. It is three inches 
 
 long and one and a half broad." 
 
 The addition to this description in Salter's trilobites is as follows : 
 Description of "The head is more than a third of the whole length, and longer than 
 ^ yP®' the thorax, which in its turn, is longer* than the caudal shield. The 
 
 head is semi-oval, rather pointed in front, and has very short posterior 
 spines ; it is broadly depressed around the margin. The glabellar por- 
 tion is scarcely marked out ; the eyes are placed nearly half-way up the 
 head ; they are small (two lines long), the facial sutures curving out 
 boldly beneath them, and cutting the posterior margin more than half 
 way out from the axis. 
 
 Above the eye they form a narrow ogive, and nearly follow the front 
 margin. On the underside of the head the vertical furrow on the epis- 
 
 *The italics are inserted to mark the points of difference from the Canadian variety. 
 
233 
 
 tome shows disfcincfcly through the cast. The labrum [hypostome] is im- 
 perfect, but exhibits a strong marginal groove, and two small lateral 
 furrows. 
 
 The body rings have the axis as broad as the sides, and moderately 
 convex. The pleurse are flat as far as the fulcrum, truncate at their ends, 
 and have but a slight groove, which reaches two- thirds of the length. 
 The fulcrum is at one-third in front, and less than half way out in the 
 middle pleurse. 
 
 The caudal axis extends three-fourths down the smooth tail, very in- 
 distinctly marked above, but in some specimens crossed by several faint 
 rings, and is always prominent at the tip." 
 
 The Cape Breton form, by its hypostome, it is cleaaly within Oalla- Other points 
 way's genus asaphellus. Allowing for the distortion of the type species, Canadian 
 figured by Salter, it is quite as large. variety differs. 
 
 Certain features, not mentioned by Salter, are characteristic of the 
 Cape Breton form. The glabella is somewhat ridged along the axial 
 line, and its margins more distinct. About one-fifth of the length of 
 the head shield from the back there is a slight but distant prominence 
 {scarcely a tubercle) on the axial line ; a fairly marked tubercle is also 
 found on the median line of the axis of the pygidium, at the back of the 
 first ring, and faint traces of similar prominences on succeeding rings. 
 
 The genal spines are not as short as Salter's description indicates for 
 the Welsh form for the points are opposite the fourth segment of the 
 thorax ; the length of the movable cheek and spine behind the facial 
 suture, is just equal in length to the part of the latter behind the eye- 
 lobe. 
 
 The eyelobes are variable in position ; in the type figured they are just 
 half way between the front and back of the shield ; in examples of the 
 narrow form they are, proportionately, further back ; and in both forms 
 the width of the middle piece in front is considerably less than at the 
 eyelobes. 
 
 In the broad form, the headshield, thorax and pygidium are each of 
 about equal length ; others have the pygidium shorter than the thorax 
 by the width of one joint. In the narrow form examples occur in which 
 the pygidium is longer than the thorax. The pygidium has more numer- 
 ous somites than A. Homfrayi as figured by Salter.* From A. affinis 
 McCoy (ibid) it differs in having the middle piece narrower in front, and 
 the glabella and axis of the pygidium more markedly elevated. 
 
 Young individuals havethe pygidium proportionately shorterand wider; 
 one of about 15 mm. in length has a pygidium equal in length to only six 
 
234 
 
 rings of the thorax. The thoracic ring is narrow, for one is equal in length 
 to the breadth of five rings. 
 
 Hypostomb. 
 
 This for A. Homfrayi seems very imperfectly known. A good example 
 of the Cape Breton variety has the following characters : 
 
 Hypostome of Hypostome 16x17 mm. main lobe ll x 11. No anterior wing or dou- 
 is species, bigm. attachment was observed. 
 
 Nearly circular, though wider towards the back than the front. It 
 has a moderately arched oval body, with a broad convex border, wider 
 towards the back. The main body of the hypostome is divided by a pair 
 of diagonal furrows that impress each outward third about two-thirds 
 from the front. Immediately behind these furrows are the maculae- sharp, 
 narrow ridges, raised above the general level of the hypostome ; no occu- 
 lar facets are visible, but there are several small, obscure pits along the 
 ridge. Were the hypostome in place beneath the glabella, the macula 
 would be opposite the eyelobe of the cephalic shield, but nearer the 
 axialine of the body. The furrow within the border is depressed at 
 the back and bordered by a narrow upturned flange, but there is no 
 emargination, nor does the border project backward in a pair of forks. 
 The hypostome is highest in the middle of the main lobe, and the convex 
 border is bent down in the middle, where it is broadest. 
 
 Development dueing growth. Young, 2 x IJ mm. 
 Development This larval form is interesting as a connecting link between several 
 
 of the young. 
 
 genera of the Asaphidse. It may be said to antedate the development of 
 the generic characters. At this stage the carapace had no flattened 
 borders, and the head shield especially was strongly bent down in front 
 and at the sides. The back of the glabella is very distinctly marked 
 out, and here the head-shield is strongly trilobed. About the middle 
 of the glabella, on the inside of the shield a flaring ridge, that appears to 
 be the back part of the eyelobe, runs out on each side from the glabella, 
 and fades away on the surface of the test. At this stage no moveable 
 cheek had been detached, but the genal corner of the shield is somewhat 
 extended into a short point. There are indications of several somites in 
 the head shield ; first the neck ring and posterior marginal fold, then a 
 pair of somites indicated by incipient furrows on the sides of the gla- 
 bella, then the ocular segment. 
 
 The thorax, at this stage, possessed two joints, with rounded rings and 
 pleuise. 
 
235 
 
 In the pygidiutn, the neopygidium and protopygidium* are distinct ; 
 the former has three rings as strongly marked off as those of the thorax, 
 the protopygidium has the same number of obscure somites. 
 
 In this larval form, which in development is close to the unsegmented 
 larva, the outline of the headshield distinctly recalls the adult in Illsenus 
 and Dysplanus, but the strongly segmented pygidium has an even more 
 generalized meaning. 
 
 Young 6x5 mm. 
 
 This moult already possesses many features of the adult. 
 
 The flattened borders are obvious on both shields, and the headshield is ^ ]ater moult, 
 broken up into the three principal pieces. The movable cheeks have 
 heavy genal spines, and the course of the suture is functionally that of 
 the adult. The slipping of the cheeks in this example has obscured the 
 eyelobe, which, however, appears to be not far from the glabella. The 
 glabella, though slightly marked elsewhere, is marked off in front by a 
 slope to the flattened margin. 
 
 The thorax now has five joints, and the pleurae has grooves and facets 
 like the adult. 
 
 The pygidium has about the same number of segments as in the younger 
 shield, but those of the neopygidium are less prominent than in the 
 younger moult ; they are, however, still discernable on the sidelobes, as 
 well as on the rachis. In this, while not agreeing with the genus Asa- 
 phellus, they recall many others of the Asaphidae. 
 
 Size. — Length of the whole carapace of the adult, 73 mm.. Length 
 of cephalic shield, 26 mm. ; of thorax, 21 mm. ; of pygidim, 26 mm- 
 Width of cephalic shield, 50 mm. ; of thorax, 43-45 mm. ; of pygidium; 
 45 mm. 
 
 Horizon and locality. — In fine gray shale of Assise C. 3 c^ at McLeod 
 brook, Boisdale, N.S. 
 
 Note on the Young of Asaphellds Homfrati. 
 
 Since writing the above in regard to the young of AsapheUus Homfrayi Young of this 
 
 the writer has consulted Dr. Callaway's article on the fauna of the Shinton Concmhry^ 
 
 Shales, t and was at once struck with the resemblance between the §?^9Pi™^'^ °^ 
 
 ■*" , ... Callavraj . 
 
 youngest form here described, and Conophrys Scdopiensis, and it is clear 
 
 that the latter is a later stage or development of the former. 
 
 * Monograph British Trilobites, p. 165, pi. 24, figs. 6-12. 
 t Quart. Jour. Geol. Soo. London, vol. xjcxiii, p. 652. 
 
 * Trans. Roy. Soc. Can. 2me. Ser., vol. iv, sec. iv, p. 145, lines 26, 27. 
 
236 
 
 There is no question that in the Canadian form three rings, of the five 
 that are strongly marked, are still a part of the pygidium ; but if they 
 were free rings there would be a remarkably close assimilation to Cono- 
 phrys, the difference being only in the greater number of rings in the 
 thorax of this genus. Looked upon as a developmental stage of Asa- 
 phellua this difference is to be expected, as our form is smaller than 
 Gonophrys Salopiensis. 
 
 The differences in the headshield are also of a kind that naturally follow 
 from the two being different stages of development. Dr. Callaway shows 
 the front lobe of the glabella as much more distinct than that of the 
 Canadian form, though he speaks of it as being " hardly distinguishable 
 from the front of the head;" in the Canadian form this lobe is barely 
 discernable, except at the sides of the glabella. Again he speaks of the 
 neck furrow being " deep," whereas iu the Canadian form it cannot be 
 discerned, and the lateral furrows are fainter and .more embryo-like. 
 Gonophrys Salopiensis therefore may very well stand as a developmental 
 stage of A. Homfrayi, somewhat more advanced than the youngest form 
 ascribed to this species from the Canadian beds. The development of 
 one genus from another in the earliest larval stages is shown in the obser- 
 vations on the development of Anomocare stenetoides from an Olenus-like 
 (Acantholenus) larva.* 
 
 o/develop- ^'^ *^^ other hand, those studies show that Conophyrs or rather Shu- 
 
 WTh ™ • mardia may be a valid genus, arrested in the phylum from which Asa- 
 and Anomo- phellus and Asapbus were elaborated ; if so, however, we should be able 
 *'*'^®" to find it in faunas from which these genera are absent. Nevertheless it is 
 
 quite possible that it might be absent from faunas which have the later Asa- 
 phi, if the Shumardia stage were passed over in the development of the later 
 forms of this family. Such a case of arrested development, and fixation 
 of larval as specific characters, seems to be presented to us in the species 
 Bathyuriscus pupa of Mt. Stephen fauna,! as well as in Acantholenus 
 spmiger* 
 
 That the form which we have described as an early moult of Asaphellus 
 Homfrayi is Asaphcjid, though so far removed from the adult in form, I 
 think is shown by its peculiar glabella, fading away at the front into the 
 frontal area of the cheeks, so that the line of demarkation between the 
 two is not clearly traceable, a very common character in the Asiphoid 
 trilobites. In this form it appears to the writer that the faint crescentic 
 lobe in the front of the glabella is homologous with the front lobe of the 
 glabella and the eyelobes collectively, and that the flaring anterior ends 
 
 * Bull. Nat. Hist. New Brunswick St. John, 1898, No. xvi, p. 40. 
 
237 
 
 of the dorsal furrows represent the posterior half of the eyelobes. The 
 obscurity of the occipital furrow is also an Asaphoid character. 
 
 If Conophrys is a valid genus Mr. E. Billings' genus Shumardia has Shumardia a 
 precedence of it by five years. S. granulosa (Billings) of the Quebec group 
 appears to be a diminutive trilobite of the same type, and from near the 
 same horizon.* S. glacicdis, of the same author, probably belongs to ano- 
 ther genus, t 
 
 The late Dr. Henry Hicks, described from the Tremadoc group in South 
 Wales, two species of " Niobe," which Prof. W. C. Brogger refers to Asa- 
 phellusj ; one of these, N. Menapiensis, is too large to compare with the 
 Cape Breton species ; the other, i\^. solvensis, dififers in the form of the 
 movable cheek, and of the hypostome. 
 
 ASAPHELLUS (?) PLANUS, PI. XVIII, fig. 11. 
 
 Bull. Nat. Hist. Soc. of New Brunswick, vol. iv, p. 419, pi. xviii, fig. 11 . 
 
 A broad oval species with smooth shield and prominent eyelobes. Asaphellus 
 
 planus. 
 
 The head shield is semicircular, with strong cheek spines. It is about 
 twice as wide as long, and has a broad fiat margin. 
 
 The middle piece of the head shield is narrowed in the middle by the 
 eyelobes being placed close to the side of the glabella. 
 
 The facial sutures are strongly arched out in front of the eyelobe and 
 turning, meet along the front margin ; the front area of the cheek thus 
 left, is wider than the middle piece at the eyelobe, and three-fifths of the 
 width at the back of the middle piece. The suture curves out boldly 
 behind the eyes, turning inward again near the posterior margin, which 
 it cuts about a third of the distance from the outer margin of the head 
 shield. 
 
 The glabella is level with the cheeks, except at the front, where it 
 slopes down to the fiattened anterior margin. The eyelobes are strongly 
 elevated, short, and placed about half way from the front of the shield. 
 There is a minute tubercle on the axial line one-quarter from the back 
 of the head. The posterior marginal furrow is short and shallow, and 
 the occipital ring narrow and obscure. 
 
 The movable cheek behind the eyelobe is nearly as wide as the Description of 
 glabella ; the front runs beneath the front margin of the middle piece in its parts, 
 a wide semi-doubleur that extends to the axial line. Posteriorly, it is 
 
 * Ibid. vol. i, p. 283, fig. 270. 
 
 t Palseozoic Fossils, vol. i, p. 92, fig. 83. 
 
 t'Euloma-Niobe Fauna, Christian '96, p. 47. 
 
238 
 
 lengthened into a genal spine, which, from the facial suture to the point, 
 is as long as the posterior extension of the suture behind the eyelobe. 
 
 The movable cheek, under the eyelobe, carries a convex band of several 
 rows of minute ocular facets arranged diagonally ; those in front of the 
 middle of the band run diagonally upward and forward, those behind 
 the middle run diagonally upward and backward. 
 
 The thorax of eight joints has long, narrow segments, terminating in 
 rounded points, strongly facetted ; the ring of the middle segment is 
 about as long as the pleurae ; the pleurae are bent (but scarcely geniculate) 
 at one-half of the length of the first segment ; they bear a quite shallow 
 furrow directed backward ; each ring of the thorax has a narrow articulat- 
 ing band. 
 
 A thorax and pygidium of smaller size, supposed to belong to this 
 species, has the following characters ; The pygidium is broadly semi-cir- 
 cular and no axis is visible ; a slight protuberance one-third from the 
 posterior end indicates the termination of the rachis ; the sides lobes are 
 sloped down to a somewhat flattened margin. On each side lobe there 
 is a shallow groove near the front. 
 
 The hypostome in this species is unknown, therefore the reference to 
 Asaphellus is provisional. 
 
 Sculpture. — The surface of the shell of this trilobite is smooth or 
 minutely punctate. The underside of the movable cheek has a rugulose 
 surface on the upper part, and a finely concentrically striated band on 
 the slope outside of this ; the flattened band is covered with widely spaced 
 anastomosing raised lines, parallel to the margin of the shield. 
 
 Distinct from The composition of the test in this species is different from that of A. 
 Homfrayi, which has a shining and polished surface as preserved in the 
 shale ; this, on the contrary, had a dull surface, and appears to be more 
 calcareous, as there is little but a film of the shell substance left, where 
 the containing shale has been exposed to weathering. 
 
 Size. — Length, about 70 mm. ; width, about 55 mm. ; length of head 
 shield about 26 mm. ; of the thorax, 20 mm. ; of the pygidium, about 24 
 mm. The pleurae are about 45 mm, long, and the pygidium of about the 
 same width. Scarce. 
 
 Horizon and locality. — The gray shales of Assise (7. 3 c.^ at McLeod 
 brook, Boisdale N.S. 
 
 A. ( 1 ) planus is distinguished from A. Homfrayi, var. by its broader 
 glabella, more prominent and more distant eyes, broader and less pointed 
 front to the middle piece of the headshield, more obscure neck furrow. 
 
 A. Homfrayi. 
 
239 
 
 narrower thoracic rings, and the smooth and obscure axis of the pygi- 
 dium. 
 
 This form might be referred to Niohe, but for the obscurity of the 
 glabella (and the almost entire absence of rachis to the pygidium, if we 
 are right in referring the smooth pygidium to this head and thorax). 
 This form cannot belong to Platypeltis, Cal., because it has eight seg. 
 ments, and no frontal enlargement of the glabella is traceable ; on the 
 contrary, the glabella is conical ly rounded, as in Asaphus. 
 
 Ctenichnites bisulcatus, n. sp. 
 
 This track I have not seen elswhere in the Cambrian rocks. The fur- Ctenichnites 
 rows are arched like those of C. ingens, but only two furrows are found 
 together and these a little over two inches apart. The impression of the 
 outer one fourteen inches or more in length, was much stronger than 
 the inner ; the latter was visible for a length of only three inches ; the 
 outer track is more strongly arched at the ends than elsewhere ; the 
 chord of the arch is about half an inch from the highest part of the arch. 
 
 Horizon and locality. — On a flag of the Johannian Division. (G. la.) 
 Falls of MacMullin brook, Indian brook, Escasonie N.S. 
 
240 
 
 Synopsis of the Species of the St. John Terrane in Cape Breton, with the 
 horizons at which they are found. 
 
 
 ^ 
 
 1 
 
 AOADIAN. 
 
 2 
 
 JOHANNIAN. 
 
 3 
 
 Bbetonian. 
 
 
 C 
 
 a 
 
 b 
 
 a 
 
 k 
 
 c 
 
 a 
 
 h 
 r 
 
 6 
 
 g 
 
 s 
 
 Ph 
 
 c 
 
 i 
 
 o © 
 
 .&§ 
 
 a 
 
 X 
 
 c2 
 
 Synopsis of Name of Species or Variety. 
 
 the Cape 
 
 Breton species 
 
 of the St. John 
 
 Terrane. 
 
 
 1: 
 
 
 182 
 183 
 185 
 186 
 183 
 187 
 189 
 190 
 192 
 197 
 193 
 199 
 204 
 207 
 200 
 203 
 204 
 203 
 206 
 209 
 209 
 210 
 213 
 217 
 
 
 
 
 
 
 
 
 
 
 X 
 
 Acrotreta sipo 
 
 
 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 X 
 
 
 
 
 
 
 X 
 
 
 
 
 Schizambon priscus 
 
 Leptobolus flumenis 
 
 L gemmulus 
 
 
 
 
 X 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 
 
 X 
 
 
 L. of. linguloides 
 
 Lingulepis Starri v. exiguna 
 
 jj var .... . . . 
 
 
 
 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 
 
 X 
 X 
 
 
 
 
 
 Lingulella radula v. aspera 
 
 L lajvis V, lens. ... 
 
 
 
 
 
 
 
 X 
 X 
 
 
 X 
 X 
 
 
 L. .; V. grandis 
 
 
 
 
 
 
 
 
 
 
 L. c. f. lepis. 
 
 Xi . c. f . Davisii 
 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 X 
 
 L. (Westonia) Escasoni 
 
 
 
 
 
 X 
 
 
 
 
 
 X 
 
 
 
 
 
 Ijinnarssonia of. Belti 
 
 
 
 
 X 
 X 
 
 
 IMonobolina ref ulgens 
 
 
 
 
 
 
 
 
 
 
 
 
 
 X 
 
 
 O. inut. strophomenoides . . 
 
 Oamarella ? 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 X 
 
 
 
 Falseacmsea, sp 
 
 
 X 
 
 
 
 
 
 
 Modiolopsie, of. Solvensis 
 
 Belleropnon insulse 
 
 B. Bretonensis 
 
 217 
 217 
 218 
 219 
 219 
 213 
 220 
 221 
 222 
 183 
 183 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 
 
 
 Beyrichia triceps 
 
 Agnostus, sp 
 
 A.. .trisectus v. ponepunetus. . 
 
 A. '- — — mut. germanus. . 
 
 
 
 X 
 
 
 
 
 
 
 X 
 
 
 
 
 X 
 X 
 X 
 X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Agnostus cf . cyclopyge 
 
 
 
 Paradoxides of. rueulosus 
 
 P, Forchhammeri. 
 
 X 
 
 
 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 X 
 
 
 
 
 
 
 
 Parabolina l)awsoni 
 
 223 
 226 
 226 
 228 
 227 
 229 
 230 
 230 
 232 
 232 
 237 
 239 
 
 
 
 
 
 X 
 
 
 
 Parabolinella (?) ouadrata 
 
 
 
 
 
 
 
 X 
 
 P. (?) cf. limitis 
 
 
 
 
 
 
 
 
 X 
 
 SphEerophthalmus alatus 
 
 S. Fletcheri 
 
 
 
 
 
 
 X 
 X 
 X 
 X 
 
 
 
 
 
 
 
 
 
 Ctenopyge pecten 
 
 Peltura scarabeoides 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Triarthrus Belli 
 
 
 
 
 
 
 
 Angelina (?) sp 
 
 Asaphellus Homf rayi var 
 
 A. planus 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 X 
 
 Otenichmtes bisulcatus 
 
 
 X 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
IN^IDEX 
 
 Page. 
 
 Acadian division on Boundary Brook 30 
 
 A. at Barachois and at Mira Eiver 39 
 
 Acrothele, development of 84 
 
 A. notes on the table of distribution 103 
 
 A. abavia, description of .*. . . 100 
 
 A. the oldest Acrothele 101 
 
 A. avia, described and compared 98 
 
 A. puteis, description of 100 
 
 A. Matthewi, var. costata, &c 104 
 
 A. proles, description of 102 
 
 Acrothyra, a characteristic Etcheminian genus 88 
 
 A. description of the genua 85 
 
 A. development of 84 
 
 A. distribution of in Basal Cambrian 85 
 
 A. shells of, markedly oriented 53, 57 
 
 A. proavia, description of 90 
 
 A. attitude of these fossils 91 
 
 A. marks the Upper Etcheminian 92 
 
 A. crassa, description of 94 
 
 A. prima, description of 93 
 
 A. signata, description of 86 
 
 A. characteristic of Lower Etcheminian 92 
 
 A. prima, description of 73 
 
 A. sera, description of : 87 
 
 A. orta and tarda described .' 89 
 
 Acrotreta, development of 84, 96 
 
 A. distribution of 85 
 
 A. subordraate of Acrothyra in Etcheminian 94 
 
 A. table showing enlargement, &c 97 
 
 A. Baileyi 97 
 
 A.^ bisecta, description of 186 
 
 A. gemmula 97 
 
 A. papillata, description of 95 
 
 A. var. lata described 95 
 
 A. mut. prima, description of ■. 73 
 
 A. sipo, description of 185 
 
 A. cf. socialis, described and compared 183 
 
 Agnostus Acadicus cf . declivis, occurrence of 223 
 
 A. cyclopyge, pygidium of found 223 
 
 A. trisedlus mut. germanus, described 221 
 
 A . mut. ponepunctus, described 220 
 
 Angelina (?) larval cephalic shield 232 
 
 Asaphellus Homphrayi, var. described 232 
 
 A. development of the young 234 
 
 A. parallel to Bathyuriscus, &c 236 
 
 A, planus, compared with other species 238 
 
 A. description of 2S7 
 
 16— C. E. 241 
 
242 
 
 Assise Co (Coldbrook) fossils of 72 
 
 Assises of Lower Etoheminian, fossils of 77 
 
 A. orientation of fossils of 55 
 
 A. Middle Etcheminian, fossils of 79 
 
 A. Upper Etcheminian, fossils of 81 
 
 Barachois basin, Coldbrook, efifusives of 13 
 
 B. differential uplift in 50 
 
 B. succession of Cambrian in , 50 
 
 Basal conglomerate of Etcheminian 17 
 
 B. of St. John gioup 32 
 
 Bellerophon Bretonensis, described and compared 218 
 
 B. insulse, described 217 
 
 B. semisculptus, described and compared 219 
 
 Beyrichia triceps, described 219 
 
 Billingsella retroflexa, described , 148 
 
 B. dimensions of valves 150, 151 
 
 Boston road, Etcheminian terrane 37 
 
 Boundary brook, Etcheminian section on 28 
 
 B. fossils of Assise E. 1 d 78 
 
 Brachiopods, orientation of valves 52 
 
 Bradoria, genus described 162 
 
 B. (?) ornata, described 166 
 
 ■ rugulosa, described, and mutation 166 
 
 - scrutator, described and compared 163 
 
 - vigilans, described 164 
 
 • mutations described 165 
 
 B, 
 B 
 B 
 B. 
 
 BradoriidEE family of Ostracods 155 
 
 Bradorona, new subgenus of Ostracods 156 
 
 Bradorona observator, description of 160 
 
 B. var. benepuncta and Isevis 161 
 
 B. mut. ligata described. , ' 162 
 
 B. perspioatgr, description of 156 
 
 B. magna and major 158 
 
 B. maxima, described 157 
 
 Bradorona spectator, description of 158 
 
 B. ■ — ^' mut. spinosa. . , 159 
 
 B.' mut sequata, described ... . ; 160 
 
 Bretonian division, Barachois road 49 
 
 B. Gillis brook. East bay 46 
 
 B. McLeod brook 49 
 
 Cambrian in Cape Breton, palseontology of 67 
 
 C. terranes of _ 11 
 
 C. • sediments, cementation of 64 
 
 C. of Cape Breton, not deeply buried 65 
 
 C. strata folded transverse to pressure from Atlantic Ocean 66 
 
 C. ■ succession in Barachois basin 50 
 
 C. in Cape Breton, similar to New Brunswick * 9 
 
 C. in New Brunswick, first classification 8 
 
 C. system, knowledge of it extended 6 
 
 C. in Sweden — faunas 7 
 
 C. in Wales, groups of .... •. 8 
 
 Coldbrook eflusives at Barachois basin 13 
 
 C. at Dugald brook, fossils in 16 
 
243 
 
 Oolbrook felsitPS in the Mira valley 16 
 
 C terrane, slates more disturbed 65 
 
 Complicated structure of Etcheminian 18 
 
 Ctenichnites bisuleatus, described 239 
 
 Cteuopyge pecten, occurs at Escasonie 229 
 
 Development of Acrothyra, Acrotreta and Aorothele 84 
 
 Differential uplift in Barachois basin 50 
 
 Dugald brook, fossils of Lower Etcheminian ; 22 
 
 Dugald brook fossils of Middle Etcheminian 24 
 
 D. section of Etcheminian on 22 
 
 Dying marine animals, buried on ebb tide 61 
 
 East bay, Peltura fauna on, fossils of 51 
 
 Eoobolus, sub genus, description of 135 
 
 JErosion of Upper Etcheminian, supposed 30 
 
 Escasona (? ?) ingens, described 168 
 
 E. new genus, described . . 167 
 
 E. rutellum, described 167 
 
 Escasona (?) vetus, described 168 
 
 Etcheminian and Coldbrook, fossiliferous zones of 71 
 
 E. complicated structure at Young brook 18 
 
 E. Division 3, assises of 25 
 
 E. faunas, species of the two compared 178 
 
 E. ' fossils of Upper Division 26 
 
 E. regional name for oldest Cambrian in New Brunswick, &c 11 
 
 E. sandstone at Spruce-brook, East bay 46 
 
 E. basal conglomerate of 17 
 
 E. : — terrane on East Bengal road 36 
 
 E. on West Bengalroad 35 
 
 E. on Boston road 37 
 
 E. on Sydney and Louisburg road 38 
 
 Eurypteroid crustacean (?) described 177 
 
 Fletcher, Mr. Hugh, earlier survey of Cape Breton 6 
 
 noticed fossils at Youngs point 18 
 
 references to the Cambrian rocks 7 
 
 Eoseilif erous zones of the Etcheminian and Coldbrook 71 
 
 Fossils in the Coldbrook terrane at Dugald brook 16, 72 
 
 Etcheminian at Dugald brook 22, 77 
 
 Division 2 at Dugald brook 24, 79 
 
 3 u 25, 80 
 
 1 at Boundary brook 29 
 
 Assise E 3f, at Gillis brook 82 
 
 Gillis brook, East bay, Johann'an and Bretonian divisions 46 
 
 €tillis brook on Indian brook, section of Cambrian 31 
 
 Gregwa brook, section of Cambrian at 31 
 
 Holasaphus fauna at Young point 70 
 
 Holasaphus, genus described 174 
 
 H. eentropyge described , 174 
 
 H. compared with other species 173 
 
 Hyolithes cf. tenuistriatus 83 
 
 16 — C. R. 
 
244 
 
 Indiana, new genus of Ostracod 169 
 
 I. lippa, described 171 
 
 I. — - — ovalis, described 170 
 
 I. mut. prima, described 171 
 
 Indian biook, plateau of Cambrian rocks 20 
 
 I. ripple marked flags on 44 
 
 I. ■ Coldbrook terrane on 14 
 
 Johannian division on Boundary brook 30 
 
 at Gillis brook. East bay 46 
 
 sandstones at Long island 40 
 
 strata at McMuUin brook 41 
 
 at Mcintosh brook 44 
 
 Leperditia (' ?) rugosa, described 155 
 
 Leptobolus, Hall, characters of the genus 105 
 
 L. valves of, decidedly oriented 54 
 
 L. atavus, description of 106 
 
 L. development of the phylum Ill 
 
 L. compared with other species 108 
 
 L. mut. insulEE, described 110 
 
 L. tritavus 109 
 
 L. coUicia, description of 112 
 
 L. v. collis, described 114 
 
 L. flumenis, description of 189 
 
 L. gemmulus, description of 190 
 
 L. cf. linguloides, description of 192 
 
 L. torrentis, description of : 74 
 
 Lingulella concinna, described 203 
 
 L. cf. Davisii, described 203 
 
 L. laevis v. grandis, described 200 
 
 L. v. lens, described 201 
 
 L. cf. lepis, description of 204 
 
 L. longovalis, n m 123 
 
 L. range and dimensions of. 124 
 
 L. cf . longoralis, range and dimensions of 75 
 
 L. radula v. aspera described 204 
 
 L. Selwyni, figure and description , 117 
 
 L. additional notes .. , 121 
 
 L. dimensions of valves 122 
 
 L. m\iscular and circulatory systems 118 
 
 L. original description 120 
 
 L. tumida, description of 123 
 
 Lingulepides, oriented in Assise E. 1 d 57 
 
 lingulepis, Hall, characters of the genus 12G 
 
 L. Gregwa, description of 126 
 
 L. . robusta, described 131 
 
 L. ornamentation and dimensions of 128 
 
 Ij. longinervis, description of 133 
 
 L. pumila, described 75 
 
 L. Roberti, description of 132 
 
 L. rotunda, n h •. 199 
 
 L. starri, var. n n 193 
 
 L. mut. exigua, described 1B7 
 
245 
 
 Linnarssonia of. Belti, described and compared 209 
 
 Long Island passage, Johannian sandstone at 4 
 
 McCodrum brook, section of Etcheminian at 33 
 
 Mcintosh brook, Johannian division on 44 
 
 McLeod brook, Bretonian fossils of 46 
 
 Tremadoc fossils on 50, 70 
 
 McMullin brook, section of Joliannian and Acadian 41 
 
 and Boundary brook 43 
 
 McNeil brook, Peltura fauna on 51 
 
 Maritime Provinces, pre-Cambrian land in 68 
 
 synoptical table of strata fi9 
 
 Mira valley, Coldbrook felsites in 16 
 
 no conglomerate at base of St. John group 32 
 
 two basins of Bretonian strata 57 
 
 Modiolopsis cf. Solvinsis, description of 217 
 
 Monobolinarefulgens, described 210 
 
 Obolus, character of the genus 135 
 
 O. scarcely affected by orientation 54 
 
 O- aequiputeis, description of 139 
 
 O. Bretonensis, dimensions, &c., of valves 143 
 
 O. discus, description of 138 
 
 O. distribution in the Basal Cambrian 147 
 
 O. lens, description of 144 
 
 O. dimensions of the valveri 145 
 
 O. V. longus, description of 146 
 
 O. triparilis, description of 136 
 
 O. torrentis, description of 76 
 
 Orientation of valves of Brachiopods 52 
 
 O. perhaps dueto shore current 61 
 
 Orthis lenticularis, description of 213 
 
 O. varieties of 216 
 
 Ostracoda of the Coldbrook terrane 76 
 
 O. of the Basal Cambrian rocks 151 
 
 O. genera of Basal Cambrian distinct 153 
 
 O. t«rms used in describing 154 
 
 O. horizons of the several species 152 
 
 Palaeobolus, subgenus described 140 
 
 Palseobolus Bretonensis, description pf 141 
 
 P. dimensions of the vsilves . 143 
 
 Palaeontology of Cambrian in Cape Breton 67 
 
 Parabolina Dawsoni, described 223 
 
 P. compared with other species 22 1 
 
 Parabolinella limitis (?), young example 226 
 
 P. quadrata (?), described 225 
 
 Paradoxidoid trilobite described 176 
 
 Pedicle of the Braohiopod in relation to orientation 53 
 
 Peltura fauna on Bast bay, &c., fossils of 51 
 
 Peltura scarabeoides at McNeil brook 330 
 
 Plateau of Cambrian rocks at Indian brook 20 
 
 Pre-Cambrian land in the Maritime provinces of Canada r 68 
 
 Pressure from the Atlantic on the Cambrian strata 66 
 
246 
 
 Sehmidtella, genua of Ulrioh 172 
 
 S. (?) acuta, described 17S 
 
 S. (!) pervetus, described 172 
 
 S. mut. concinna, described 17S 
 
 Sohizambon prisous, described and compared 187 
 
 Section of Cambrian on Dugald brook 22 
 
 S on Gregwa brook 31 
 
 Section of Etcheminian at Steele brook 20 
 
 Lower Etcheminian at Young point 19 
 
 Shore current, probable cause of orientation 61 
 
 Slates and sandstones of the Etcheminian , 17 
 
 Solenopleura Bretonensis, described 176 
 
 Slates of Coldbrook terrane disturbed 65 
 
 Sphserophthalmus alatus, found 9 
 
 S. Fletcheri described 227 
 
 S. comparative abundance 228 
 
 Spruce brook. East bay, Etcheminian at 46 
 
 St. John terrane, descriptions of the species of the 183 
 
 faunas of the 180 
 
 lists of the species of 182 
 
 synoptical table of species 240 
 
 Steele brook, Etcheminian section at 20 
 
 Sydney and Louisburg road, Etcheminian on ~ 38 
 
 Table, synoptical, of Cambrian strata 69 
 
 Terranes of the Cambrian in Cape Breton 12 
 
 Thickness of Oambrian in Cape Breton 52 
 
 Tremadoc fossils on McLeod brook 50, 70 
 
 T. fauna, is it Cambrian ? 180 
 
 Triarthrus Belli, described and compared 230 
 
 Upper Paradoxides fauna on McLean brook 70 
 
 Urotheca, a species of 183 
 
 West Bengal road, Etcheminian on 35 
 
 Westonia, subgenus of Walcott, described 205 
 
 Escasoni described 206 
 
 — beautifully ornamented 207 
 
 compared with other species 208 
 
 Young point, Holasaphus fauna at 70 
 
 orientation of fossils variable 63 
 
 Section of Lower Etcheminian at 19 
 
 Zone "Co.," comparatively small size of fossils in 72 
 
PLATE I. 
 
 Fio. ]. Acrothyra signata mut. prima 2^ x 2J x IJ m.Mag. f ; — re Ventral valve; — b 
 Mould of interior of same ; — c Ventral from the side ; —J Another ventral 
 with low umbo ; — e Dorsal valve ; — f Mould of the interior ; — g Dorsal from 
 the side. From Colbrook group at Dugald brook, Escasonie, N. S. See p. 73. 
 
 Fig. 2. Acrothyra signata 3x2x1 mm. Mag. Y ; — a Ventral valve ; — 6 Mould of 
 the interior ; — c Ventral valve from the side ; — d Dorsal valve ; — c Mould of 
 interior of same. From Assise E. 16 (Lower Etcheminian), Dngald brook, 
 Escasonie. See p. 87. 
 
 Fig. 3. A. signata mut. sera, 2J x 2| x li. Mag. \° ; — a Ventral valve ; — 6 Mould 
 of interior of same ; — e Ventral from the side ; — d Dorsal valve ; — t Mould 
 of interior ; — /Dorsal from the side. From Assise E. \c (Lower Etchemin. ) 
 at Dugald brook, Escasonie, N. S. See p. 87. 
 
 Fig. 4. A signata, mut. orta, 2 x 1| y 1 mm. Mag. V > — « Ventral valve, mould 
 of interi jr showing visceral callus ; — 6 Another narrower, showing traces of 
 extension of the callus ; —c Ventral from the side ; — d Dorsal valve ; — e Mould 
 of interior of the dorsal ; ^ Dorsal from the side. From Assise E. 2c (Lower 
 Etchemin. ) at Dugald brook, Escasonie, N. S. See p. 89. 
 
ACROTHYRA, 
 
 i3 
 
PLATE II. 
 
 Fie. 1. Acrothyra signata mut. tarda, 24 x 3 x IJ mm. Mag. V ; —a Ventral valve 
 from above ; —6 Mould of interior of a ventral-; — c Same seen from behind ; 
 —d Ventral valve from the side. From Assise E. Id (Lower Etchemin. > 
 at Dugald brook, Bsoasonie, N. S. See p. 89. 
 
 Fig. 2. Acrothyra proavia, 2 x IJ x J mm. Mag. Y > — <* Ventral valve ; — 6 Same from 
 behind ;— c Same from side ;—d Dorsal valve ; — e Mould of the inside of this 
 valve ;— / Dorsal from the side ;— (/ Outline of the two valves, from the side. 
 From Assise E.3c (Upper Btohemin.) at Dugald brook, Esoasonie, N. S. See 
 p. 90. 
 
 Fig. 3. A. proavia, larg^ valves, 3 x 2J x | mm. Mag. Y 5 — "■ Ventral valve ; — 6 
 Another ventral with corrugated front ; — c Ventral from the side ; — d Dorsal ; 
 — c Mould of interior of the dorsal ;—/ Dorsal valve in profile. From Assise 
 E 3e, lower part, (Upper Etchemin. ) at Dugald brook, Escasonie, N. S. See 
 p. 90. 
 
 Fig. 4. A. proavia, mut, prima, 3 x 2 x IJ mm. Mag. \° ; — aVentral valve ; — 6 Mould 
 of interior — c Ventral, from the side ; — d Dorsal valve ;— c Mould of interior ; 
 — f Dorsal from the side. From Assise J!. 3a (Upper Etchemin. ) at Dugald 
 brook, Escasonie, N.S. See p. 93. 
 
 Fig. 5. A. provia, mut. crassa, 2J x 2 x 2 IJ mm. Mag.^ ; — a Ventral valve ; — 5 Mould 
 of same ; — c Ventral from the side. From Assise E. 3c, lower part, (Upper 
 Etchemin.) Dugald brook, Escasonie, N. S. See p. 94. 
 
n 
 
 ACROTHYRA. 
 
 ■la. 2a 
 
 Plate IT. 
 
PLATE III. 
 
 Fig. 1. Acrotrcia papillata, 2^ x 2J; x 1^ mm. Mag. Y— « A narrow ventral valve ;— 
 6 Same from the side ;— c Mould of interior of a ventral valve ;— d Dorsal 
 valve ;—e Same from the side ;— / Mould of interior. From Assise E. Irf 
 (Lower Etchemin.) at Boundary brook, Escasonie, N. S. See p. 95. 
 
 Fig. 2. papillata, mut. prima, 2 x 24 x IJ mm. Mag. f ;— a Ventral valve ;— 6 Same, 
 side view ;— c Mould of ventral. From the Ooldbrook Group, Dugald brook, 
 Esoasonie, N.S. See p. 73. 
 
 Fio. 3. A papillata var. lata, 2 x 2A x IJ mm. Mag. Y ;— « "Ventral, mould of interior ; 
 —b Same from the side ;— c Same from behind. From Assise E. Id (Lower 
 Etchemin. ) at Boundary brook, Eseasonie, N. S. See p. 95. 
 
 Fig, 4. Acrotreta gcmmula, IJ x IJ x L ram. Mag. Y 5 — «• Ventral from behind ; — 6 
 Same from the side ; — c Ventral, mould of interior ; — d Dorsal, interior. 
 From Protolenus Beds (C. U), Hanford brook N. B. See p. 97. 
 
 Fig. 5. Acrotreta of. socialis, v. Seebaoh 3 x 3 x 2 mm. Mag. { (except e. and k.) ; — 
 a Ventral valve;— 6 Same from the side; — c Mould of interior; — d Same 
 from the side ;—e Apex of the mould, mag. f ;— / Dorsal valve ;— ff Same 
 from the side ; — h Mould of interior ; — i Same from the side ; — k Enlargement 
 of surface sculpturing, mag. y. From Lingulella radula Zone, (St. JohnGr: 
 C.2c), McNeil brook, Mira, N. S. See p. ]83. 
 
ACROTRETA. 
 
 la. 
 
 Aa. 
 
 4Tb- 
 
PLATE IV. 
 
 FlQ. 1. Acrotreta Baileyi, 3^x4x1 mm. Mag. $; — a Ventral, mould of interior.; — 
 6 Same from the side ; — c Dorsal, mould of interior ; — d Same from the side. 
 (C.ld) Lower Paradoxides Beds, Kings Co., N. B. See p. 97. 
 
 Fio. 2. Acrotreta bisccta- 3 x 3J x S^ mm. Mag. f ; — a Ventral valve; — 6 Mould of 
 interior from the side ; — c Same seen from above ; — d Dorsal valve ; — c Mould 
 of interior from behind ;—/ Same from the side;— <; Same from above. From 
 the Dietyonema Beds, (C.3c) McLeod brook, Boisdale, N. S. See p. 186. 
 
 Fig. 3. Acrothele abavia, 6f x 6J x f mm. Mag, -} ; — a Ventral valve, interior, 
 the umbo is filled with a plug of fine sand ;— 6 Same from the side ;— c Dorsal 
 valve, interior, the shell is broken away at the umbo ; — d Same from the side. 
 From Assise E.3a (Upper Etohemin.) at Dugald Brook, Esoasonie, N. S. See 
 p. 100. 
 
 FiQ. 4. Acrothele dbavia, 5J x 6 x 1 mm. Mag. ^; — a Ventral valve, interior; — 
 6 Dorsal valve, interior. From Assise E.36 (Upper Etohemin.) at Dugald 
 brook, Escasonie, N. S. See p. 100. 
 
 Fig. 5. Acrothele avia, mut. puteis, 6 x 6i x 1 mm. Mag. f ; — a Ventral valve, 
 mould of interior ; — b Dorsal valve, interior. From Assise E. 3d (Upper 
 Etohemin), Dugald brook, Escasonie, N. S. See p. 100. 
 
 Fio. 6. Acrothele Matthewi var. costata, 5x6 mm. Mag. f. From the Protolenus Beds 
 (C. 1!/), Hanford brook, St. John Oo., N. B. See p. 104. 
 
 Fio. 7- Acrothele avia — Enlarged sculpture. See Plate V. 
 
ACROTRETA _ ACROTHELE. 
 
 Plate IV. 
 
 3i 
 
 3cl 
 
 la. 
 
 7b 
 
 t- Svi5:3 
 
PLATE V. 
 
 FiQ. 1. Acrothele avia x 10 x 1 mm. Mag. f (except c. to/.) ; — « Ventral valve, cen- 
 tral part ; —b Same seen from the side ; — o Ventral, interior of ; —d Dorsal 
 valve;— c Same in outline;—/ Dorsal, interior— c. to/, mag. f. Fig. 7 of 
 Plate IV ; —a Surface sculpture on lateral slope of ventral ; —6 Sculpture 
 on middle part of ventral. Both mag. Y- AH from Assise E. 3e (Upper Etche- 
 min) at Dugald brook, Eacasonie, N. S. See p. 98. 
 
 Fig. 2. Acrothele avia, broad form, ventral, 7 x 9^ x 1 mm. Mag. f. Dorsal 5J x 7 mm., 
 mag. f ; —a Ventral valve ; —b Dorsal valve, mould of interior. From Assise 
 E. Sd (Upper Etchemin) at Dugald brook, Escasonie, N. S. See p. 99. 
 
 f'iG. 3. Acrothele proles 8J x 9 x 1 mm. Mag. f ; — a Ventral valve ; —b Interior of same ; 
 — c A smaller dorsal valve; — d Interior of same; — c Outline of the valves 
 from the side. From Assise E. 3/ (Upper Etchemin. ) at Gillis', Indian brook, 
 Escasonie, N. S. See p. 102. 
 
 Fio. 4. Acrothele Matt hewi, Hartt, mwt. prima. Mag. | ;— a Ventral valve, shuvjring the 
 umbo close to the posterior margin ; — 6 Same in profile. From Protolenus 
 Beds (C. 16), Hanford brook, N. B. See p. 104. 
 
 Fig. 5. Acrothele Matthewi. Mag. f ; — a Dorsal valve, interior, showing median septem 
 and its branches, and fine striae on the valve radiating to the anterior and 
 lateral margins ; — 6 This valve in profile. From Lower Paradoxides Beds (C. 
 Ic), Hanford brnok, N. B. See p. 104. 
 
 Fig. 6. Acrothele Mattcwi mat. lata. Mag. f ; — a Ventral valve, interior ; has two pits 
 in front of the foramen, diverging arched ridges on each side of the foramen, 
 and a low ridge on each side of the foramen extending to the hinge line ; — b 
 A dorsal in profile, showing the position of the hinge line. From Protolenus 
 Beds (C. 1 6), Hanford brook, N. B. See p. 104. 
 
ACROTHELE. 
 
 17 C. K. 
 
PLATE ri. 
 
 Fig. 1. Leptobolus torrentis, II s^). Ventral valve partly exfoliate 1 Mag. f from Cold- 
 brook terrane. Dugald brook, Escasonie, N. S. See p. 74. 
 
 Fig. 2. Lepiobolus atavus, a Ventral valve ; — 6 ; — Mould of interior ; — d Dorsal valve ; — 
 e Mould of interior ; — f Another showing median and lateral septa. All Mag. 
 f ; — g Portion of outer surface of the shell, Mag. Y- From Assise E. 3e. Du- 
 gald brook, Escasonie, N . S. See p. 106. 
 
 Fig. 3. Leptdbolus collicia, — a Ventral valve ; — b Dorsal valve ; — c Interior of a broken 
 ventral valve. All Mag. f ; — d Another ventral showing callus of visceral cavity ; 
 — Mag. f ; — e Section of two valves, Mag. f . From Assise E. 3c, Dugald brook, 
 Escasonie, N. S. See p. 112. 
 
 Fig. 4. Leptdbolus atavus, raut. inaulce, n. mut. ;— a Mould of interior of ventral valve ; — 6 
 Mould of interior of dorsal valve ; — c Dorsal valve. All Mag. f . From Assise 
 E. 2 (a ?) Young Point. See p. 110. 
 
 Fig. 5. Leptoholus atavus, mut. tritavus, n. mut ; — a Ventral valve ; — 6 Dorsal valve, 
 exfoliated at the umbo. Both Mag. } ;— o A part of the surface enlarged/ to 
 show the sculpture, Mag. ^ ; — From Assise B. Id. Boundary brook Escaso- 
 nie, N. S. See p. 109. 
 
 FiO. 6. Liriguiellaiumida;— a VentrB,] valve; — b Mould of interior;— c Longitudinal 
 section. All Mag. f ;— From Assise E. 3e. Dugald brook Escasonie, N. S. 
 See p. 123. 
 
LEPTOBOLUS LINGULELLA. 
 
 Plate VI. 
 
 17| — c. R, 
 
PLATE VII. 
 
 Pig. 1. — Lmgulella SeVwym. — a, mould of interior of ventral valve.^6. mould of interior 
 of dorsal valve. Both Mag. f — c. Visceral and lateral areas, Mag. f to show 
 the muscle scars, vascular trunks, aiid hinge area. From Assise E. 2 (a ?) at 
 Young point, Cieorge river, N. S. See p. 116. 
 
 Pig. 2. — Lingulella cf. longovalis. Dorsal valve, umbo broken, Mag. f. From the Cold- 
 brook terrane at Dugald brook, Bsoasonie, N. S. See p. 75. 
 
 Fig. 3. — Lingulella longovalis, n sp — a. Ventral valve, partly exfoliated. — 6. The same 
 valve, mould of. — c, dorsal valve. — d. mould of the dorsal. — c. section of the 
 two valves. All Mag. |. — f. A portion of the surface of the shell Mag. Y *o 
 show the sculpture. All from Assise E. 1 c. Dugald brook, Escasonie N. S. 
 Seep. 123. 
 
 Fig. 4. — Obelus lens, var. longus, u. var. — a, Ventral valve mostly exfoliated — 6. Dorsal 
 valve. Both Mag. f. From Assise E. 3 e. Dugald brook, Eseasonio, N. S. 
 Seep. 146. 
 
 Fig. 5. — Lingulepis pwmila u sp. — a, Ventral valve. Mag. \ — h. Dorsal valve mag. f. 
 Both from the Coldbrook terrane, Dugald brook, Escasonie, N. S. — Seep. 75. 
 
 Fig. 6. —Lingulepis longinervis, n sp. — a Ventral valve — 5. Mould of the same. Both 
 mag. f — c, Cardinal area of this valve. Mag. f , — d, Longitudinal section of 
 this valve — e, Dorsal valve partly exfoliated. Both mag. f— /. Interior of a 
 small dorsal Mag. { — g. Longitudinal section of the same. All from Assise 
 E. 2 b. Dugald brook, Escasonie, N. S. See p. 133. 
 
LINGULEPIS LINGULELLA. 
 5h 
 
 ^4& 
 
 ■^\ 5 a 
 
PLATE VIII. 
 
 Fig. 1. Oholus torrentis n. ap.— Dorsal, crushed in front. Mag |. From Coldbr'ook 
 terrane, Dugald brook, Escasonie N. S. See p. 76. 
 
 Fig. 2. Obolus ceguiputein, n. sp. — a Ventral valve ; —b Interior of ventral, both Mag. 
 { ; — c Dorsal valve ; —d Mould of interior of same. Both Mag. J ;— c Por- 
 tion of the surface of a valve, Mag. V- All from Assise E. 2 (a?) Young point, 
 George river, N. S. See p. 139. 
 
 Fig. 3. Obolus discus, n. sp. — a Ventral valve, partly exfoliated ; — 6 Dorsal valve, 
 exfoliated ; — c Mould of a dorsal valve. The three Mag. f ; —d Hinge area 
 of the dorsal. Mag. f . All from Assise E le Dugald brook, Escasonie, N. S. 
 See p. 138. 
 
 Fig. 4. Obolus triparilis, n. sp. — a Ventral valve exfoliated ; — b Interior of dorsal valve ; 
 — c Section, longitudinal, of ventral valve. All Mag. ^. From Assises E. 
 16 and o Dugald brook, Escasonie, N. S. (See also next plate). See p. 136. 
 
 Fie. 5. Lingulepis Soberti — a Interior of ventral valve ; — 6 Interior of dorsal valve. 
 Both Mag. f. From Assise E. 2 (a?) Young point, George river, ]V. S. 
 Seep. 132. 
 
OBOLUS LINGULEPIS. 
 
 
PLATE IX. 
 
 Fig. 1. Obolus triparilis, a, sp. — a Mould of the dorsal valve ; — 6 Longitudinal section 
 of this valve. Both Mag. f . From Assise E. 16 Dugald brook, Escasonie 
 N. S. See p. 136. 
 
 Fig. 2. Obolus Bretonensis—a Ventral valve ; — 6 Interior of same ; — c Longitudinal 
 section of same; —d Dorsal valve; — e Interior of same ; — /Longitudinal 
 section of the two valves. All mag. f . g Portion of the surface enlarged to 
 show sculpture, Mag. | ; — h a portion further enlarged. Mag. f- From 
 Assise E. 3d. Dugald brook, Escasonie, N. S. See p. 141. 
 
 Fig. S.—LiTigidepis Oregwa — a, ventral valve, 6, interior ofjthe same, — c. Longitudinal 
 section of the same— d, dorsal valve, — e, mould of the same,^, Longitudinal 
 section of the same. All mag. f. From Assise E. 1 d. Dugald brook, 
 Escasonie, N. S. See p. 126. 
 
 Fig. i.—HyoUthes cf. tmuistriatus {and cf. princeps)—a, Tube, from the ventral face— 5, 
 same from the left side. Mag. f. From Assise E. 2] (a?) Young point, 
 George river, N. S. See p. 83. 
 
OBOLUS LINGULEPIS HYOLITHES. Plate IX, 
 
 2eL ^^ 
 
 ^S 
 
 ^m 
 
 ZK 
 
 
PLATE X. 
 
 Fig. 1. — Obolus lens. — a, ventral valve — 6, interior of same, — c, longitudinal section of 
 same, — d, dorsal valve, — e, interior of same, — f, longitudinal section of same. 
 All Mag. J, except fig. 1 6, which is enlarged 2^. All from Assise E. 3 c at 
 Dugald brook, Escasonie. See p. 144. 
 0. lens, var. longus, u. var. See pi. vii, fig. 4. See p. 146. 
 
 Fig. 2. — Billingsdla retrojlexa — a, mould of ventral valve — 6, another mould narrowed 
 by pressure, showing vascular trunks — c, mould of the dorsal valve — d, mould 
 of the exterior of the dorsal — e, longitudinal section of both valves. All Mag. 
 f. From Assise E. 2 (a?) Young point, George river, Escasonie, N. S. 
 See p. 148. 
 
 Fig. 3. HolasaphMS centropygc. — a middle piece of the head shield ; — 6 Pygidium ; — c 
 Movable cheek. All Mag. ^. From Assise E 2 [a?) at Young point, George 
 ■ river, N. S. See p. 174. 
 
OBOLUS BILLINGSELLA HOLASAPHUS. Plate X, 
 
 2e 
 
 ' 51 
 
PLATE XI. 
 
 Fig 1. Paradoxidoid trildbite.—'E'eaigraeia.t of the glabella ;— 6 Part of movable cheek ; — 
 c Pygidium ; — d A posterior pleura ; —e Ring of the thorax. All natural size. 
 From Assise E. 2 (a ?) Young point, George river, N. S. See p. 176. 
 
 Fig. 2. Solenopleura Bretonensis n sp.— a Middle piece of the head ; — 6 Supposed 
 movable cheek ; — c A pleura. All Mag. }. From Assise E. 3. /. The head 
 from Gillis-Indian brook, the cheek and pleura fromDugald brook, Escasonie, 
 N. S. See p. 176. 
 
 ¥10. 3.— Eurppteroid crustacean? Carapace abraded in front. Mag. f . From Assise 
 E. 3 f. Gillis-Indian brook, Escasonie, N. S. See p. 177. 
 
 Fig. i.—MonohoUna rcfulgens—a, Interior of ventral valve— Legend— a' Pedicle 
 groove — 6^ Anterior adductor — c^ Traces of vascular trunks — d^ Lateral 
 septum— c^ Mesian scar. Mag ?. b. Interior of dorsal valve— Legend 
 — a^ Cardinal line — h^ Posterior adductor — c^ Anterior adductor — d^ Lateral 
 septum — e' Place of anterior lateral — f^ medium septum. Mag. |. From Navy 
 island, St. John, N. B. Band C. 3 c. (See also PI. xvi, fig. 2.) See p. 210. 
 
 Fig. 5. — Acrotreta hisecta — a Ventral valve, side view — 6, Mould of interior of this valve 
 — c, Mould seen from above — d, Dorsal valve — c. Mould of interior of same, 
 seen from behind — /, Same seen from the side — g^ Same seen from above. All 
 Mag. f . From Band C. 3c, McLeod brook, Boiadale, N. S. See p. 186. 
 
 Fig. 6. Schizambon prisons ; — a Interior of ventral valve ; — h Longitudinal section ; — 
 c Interior of the dorsal valve ; — d Longitudinal section. All Mag. f . From 
 Band C 3o. McLeod brook, Boisdale, N. S. See p. 187. 
 
 Fig. 7. Leptobolus flumenis, n sp ; — a Ventral valve ; — 6 Mould of interior of same ; — 
 c Longitudinal section of same ; —d Dorsd,l valve ; —e Moulji of interior of 
 same ; — / Longitudinal section of same ; — Band C 2. c McNeill brook, Mira 
 river N. S. See p. 189. 
 
1a. 
 
 TRILOBITA BRACHIOPODA. 
 1h ZOL 
 
 Plate XL 
 
 "id. ... 
 
 ..Sh 
 
 7c 7/ 
 
PLATE XII. 
 
 FiGB. 1 to 6. — Diagrammatic figures of genera to show important character referred to in 
 the text— 0, ocular tubercle — m, soar of adductor muscle — c, cardinal or hinge 
 line — a, anterior cardinal curve — 5, posterior cardinal curve — e, anterior mar- 
 ginal curve — d, posterior marginal curve — v. ventral margin. See p. 154. 
 
 Fig. 7. Leperditia (??) rugosa.—a, right valve, side view — h, same from the front 
 —e, same from the hinge. All Mag. f, Assise E. 3. /. Gillis— Indian brook, 
 Escasonie, N. S. See p.. 155. 
 
 Fig. 8. Bradorona perspicator.—a, left valve, side view— 6, same from behind —e, 
 same from the hinge. All mag. i—d, a portion of the shell further mag.V- 
 Assise E. 1. d. Dugald brook, Escasoni, N. S. See p. 156. 
 
 Fig. 9. B. perspicator, mut. maxima. — a, right valve, side view — 6, same from 
 the front. Both Mag. f , Assise E. 1 c. Dugald brook, Escasonie, N. S. See p. 
 157. 
 
 Fig. 10. jB. perspicator, mut. major.— a, right valve, side view— 6, same from 
 the front. Both Mag. f , Assise E. 3. /. Gillis— Indian brook, Escasonie> 
 N. S. See p. 158. 
 
 Fig. 11. B. perspicator, mut. magna. — a, right valve, side view — 6, same from 
 the front. Both Mag. f , Assise E. 2 6. Dugald brook, Escasonie, N. S. See p. 
 158. ■ 
 
 Fig. 12. Bradorona spectator. — a, left valve, side view — 6, same from the front — 
 0, same from the hinge — d, mould of the upper front corner of a right valve 
 showing ocular tubercle and muscle scar. All Mag. \, Assises E. 1 c. and d. 
 Dugald brook, Escasonie, N. S. See p. 158. 
 
 Fig. 13. B. spectator, mut. spimosa. — a, left valve, side view — 6, same from the 
 front. Both Mag. \. Assise E. 1 c. Dugald brook, Escasonie, N. S. See p. 
 159. 
 
 Fig. 14. B. spectator, mut. CEquata. — a. left valve, side view — 6, same front view. 
 Both mag. f . Assise E. 3 d. Dugald brook, Escasonie, N. S. See p. 160. 
 
 Fig. 15. Bradorona observator. — a, left valve — b, same from t'ne front — c, same 
 from the hinge. All Mag. f . Assise E. 1 d. Dugald brook, Escasonie, N. S. 
 Seep. 160. 
 
 Fig. 16. B, observator var. benepuncta. — Carapace partly opened, the valves 
 laterally foreshortened. Mag. f . Assise E. 1 d. Dugald brook, Escasonie, 
 N. S. Seep. 161. 
 
 Fig. 17. B. observator mut. ligata. — Left valve, side view. Assise E. 3 e. Dugald 
 brook, Escasonie, N. S. See p. 162. 
 
ETCHEMINIAN OSTRACODA. 
 
 Plate XII. 
 
 I n.ai ( 
 
 ;2. 3 ^ 
 
 3fa.oiorona. Xtfrvthona. Kippontchano-n. 
 -£ =^ c 
 
PLATE XIII. 
 
 Pig. 1. — Bradoria scrutator— a, left valve, side view — 6, transverse section — c, longitu- 
 dinal section. All Mag. J. Assise E 3 c and/, Dugald brook, Escasonie, 
 N. S. See p. 163. 
 
 Fig. 2.— Bradoria vigilans— It, right valve, s^de view — 6, outline from front— c, outline 
 from the hinge. All Mag. J, Assise E 3 c. Dugald brook, Escasonie, iSf. S. 
 N.B. — The ocular tubercle is too near the hinge line in figs. 2 6 and 2 a. — 
 See p. 164. 
 
 ElG. 3. — Bradoria rugulosa — a, right valve, side view — 6, outline from front — c, outline 
 from hinge line. All Mag. f — d, part of the shell further enlarged (*f-) to show 
 sculpture. Assise E 3 c. Dugald brook, Escasonie, N. S. See p. 166. 
 
 Fig. 4. Bradoria ? ornata, n. sp. — a, right valve, side view — 6, outline from the front — 
 c, outline from'the hinge. All Mag. f. Assise E. 1 c. Dugald brook, Esca- 
 sonie, N. S. See p. 166. 
 
 Fig. 5. — Escasona rutellum, n. sp. — a, right (?) valve, side view — 6, same front view — c, 
 same from the hinge. All Mag. {. Assise E. 3/. Gillis — Indian brook, 
 Escasonie, N. S. See p. 167. 
 
 Fig. %.—Escascma ? vetus^ n. sp.— a, right (?) valve — 6, same from the hinge. Both Mag. 
 5. Assise E. 1 d. Dugald brook, Escasonie, N. S. See p. 168. 
 
 Fig. 7. — Escasona (??) ingens, n. sp. — a, left (?) valve — 6, same from the front — c, same 
 from the hinge. AH Mag. f . Coldbrook terrane. See p. 168. 
 
 Fig. 6.— Indiana avails, n. sp. — », right valve, side view — 6, same from the front — c, 
 same from the hinge. All Mag. f. Assises E. 1. e and 3 c. Dugald brook, 
 Escasonie, N. S. See p. 170. 
 
 Fig. 9.-7. ovalis mut prima, n. mut. — a, right valve, side view — 6, same from the front 
 — c, same from the hinge. All Mag. f . Coldbrook terrane. See p. 171. 
 
 Fig. 10.— Indiana lippa, n. sp. — a, carapace, right side— J, same from the hinge— c, same 
 from the front— rf, same from behind. All Mag. f. Assise E. 3/. Dugald 
 brook, Escasonie, N. S. See p. 171. 
 
 Fig. 11. — Schmidtella (?) pervetus—a, right (?) valve, side view — b, transverse section— c, 
 longitudinal section. All Mag. |. Assise E. 3 e. Dugald brook, Escasonie, 
 N. S. See p. 172. 
 
 Fig. 12. — Schmtdtelkt acuta — a, right (?) valve, side view — 6, transverse section— c, longitu- 
 dinal section. All Mag. {. Assise E. 3 c. Dugald brook, Escasonie, N. S. 
 See p. 173. 
 
ETCHEMINIAN OSTRACODA. 
 a 2«- 2b 
 
 4a. 4t 
 
 11 a ^1 t 
 
 /2c 
 
 18— C. B. 
 
PLATE Xir. 
 
 Fig. 1. Leptobolus gemmulus. — a Ventral valve- -6 Interior of same — c Interior of dorsal 
 valve. All Mag \. From Band C 3 c. McLeod brook, Bcisdale, N. S. 
 See p. 190. 
 
 Fig. 2. Lingulepis Starri var. — a Ventral valve partly exfoliated ; — 6 Mould of interior 
 of same, partly uncovered ; — c Mould of the dorsal valve. All Mag. ^. 
 From Band C 26. McLean brook, Mira river, N. S. See 193. 
 
 Fig. 3. Lingulepis Starri var. exigua n. var. ; — a Ventral valve, beak broken ; — 6 
 Mould of interior, partly uncovered ; — c Dorsal valve ; — d Interior of same. 
 All Mag. f. From Band C2aat McLean brook, Mira river, N. S. See p. 197. 
 
 Fir. 4. Lmgulepis rotunda, n. sp. — a Ventral valve ; — 6 mould of interior of same ; — 
 c Longitudinal section of same ; — d Dorsal valve ; — e Interior of same ; — 
 / Longitudinal section of same. All Mag. -J. From Band C 3c. McNeill 
 brook, Mira river, N. S. See p. 199. 
 
 Fig. 5. Lingulella conowma. — a Ventral valve ; — 6 Interior of same. Both Mag. {. 
 From Band C Sc, McLeod brook, Boisdale, N. S. See p. 203. 
 
LEPTOBOLUS LINGULEPIS. Plate XIV. 
 
 Za 
 
 4c 
 
PLATE XV. 
 
 Fio. 1. LmguleUalcevis var. grandis, ii. var.— a Interior Of ventral valve (Legend, 
 a Pedicle groove, b Pseudodeltidimr), v Areal border, d Transmedian muscle- 
 scar, e Soar of laterals, / Lateral septum, bordering vascular trunk, g Position 
 of anterior adductor ? h Pront of visceral callus, i Deltidial suture, j Sinew 
 of pedicle ? — k, point of attachment of same ? — Valve mag. f . 6, Cardinal 
 area and. pedicle and pedicle mag. f to show the core and muscular coat 
 of the pedicle— cross section of same Mag ^. All from Band C. 3 o 
 at St. John, N. B. See p. 200. 
 
 Fig. 1. Jymgulella Icevis var. grandis, n. var. — d, Interior of tlie dorsal valve part- 
 ly exfoliated— (legend— «, Areal border — 6, Deltidial suture— c, place of umbonal 
 muscle, — d, umbonal sear? — c, parietal band — -/, lateral branches of vascular 
 trunks — g, transmedian muscle (?) laterals bthind it, h, adductor muscles, i, 
 median septum—/, anterior lateral muscle — k, print of vascular trunks — ;, 
 mantle border — m, median sulcus, n, traces of vascular rays). Valve magni- 
 fied J. From Band C. 3 a, at Escasonie shore. East bay, N. S. See p. 200. 
 
 Fig. 2; Lingulella radula var. aspera n. var.— a, ventral valve — 6, mould of interior of 
 same, mostly uncovered — d, another mould quite decorticated. All Mag. 
 J. From Band C. 2 c, at McNeUl brook, Mira river, N. S. See p. 204. 
 
 Fig. 3. LmgulcUa Icevis, var. lens, — a, ventral val\e — b, mould of interior of same, 
 e, longitudinal section of same — d. dorsal valve — e, interior of same — ■/, longi- 
 tudinal section of same. All mag. f . —g, sculpture of a layer at the margin 
 of the shell — h, sculpture toward the median line . Both magnified }. All 
 from Band C. 3 a at Escasonie shore. East bay, N. S. See p. 201. 
 
LINGULELLA. 
 
 Plate XV. 
 
PLATE XVI. 
 
 Flu. 1. Wcstonia Escasoni ; —a Ventral valve ; — b Interior of the same ; — c Longi- 
 tudinal section of same ; — d Dorsal valve ; — e Interior of the same ; — 
 / Longitudinal section. All Mag. f ; — g Enlargement of visceral area of ven- 
 tral valve to show the central group of muscle scars ; — (Legend h. Anterior 
 adductor and "k " lateral, k place of the sinew of the pedicle, I scar of the 
 " 1 " lateral, ti Front of the visceral callus.) Mag. ^'^; — h Outer surface. 
 Mag. -^ ; — i Sculpture of second layer of the shell. Mag. \°. All from 
 Band C. 36, Escasonie shore, East bay, N. S. See p. 206. 
 
 Fig. 2. Moiiobohna refulgens. — Interior of the ventral valve ; — b Mould of interior of 
 dorsal valve. Both Mag. i. From Band C 3c, McLeod brook, Boisdale, 
 N. S. (See also PI. xi, fig. 4.) See p. 210. 
 
 Fig. 3. Linnarsscmia c.f. Belli. — a Ventral valve; — 6 Mould of interior of same; — 
 c Mould of interior of dorsal valve. All Mag {,. From Band C 3e, McLeod 
 brook, Boisdale, N. S. See p. 209. 
 
 Fig. 4. Beyrichia triceps, n. sp. — a Right valve ;— 6 Same from the front ; — c Same from 
 the ventral edge. All mag. Y- From band C2b, McLean brook, Mira river, 
 N. S. See;p. 219. 
 
WE8T0NIA MOKOBOLINA BEYRICHIA, 
 
 H 
 
 
 Za. 
 
 U 
 
 -I- 
 
PLATE XV n. 
 
 Fig. 1. Orthis Unticularis — a Ventral valve ; — 6 Dorsal valve ; — c Mould of interior 
 of ventral (Legend, a^ Adductor muscle, 6^ Diductor muscle, d^ Cardinal area, 
 0^ Ovarian space); —d Mould of interior of dorsal (Legend 6' Diductors, 
 d^ Cardinal area, o^ Ovarian space). All mag. f. From Band C 3c, Navy 
 island, St. John. See p. 213. 
 
 Fig. 2. Orthis Unticularis var. lyncioides. — a Young ventral valve ; — 6 Full grown 
 ventral ; — c Small dorsal valve. All Mag. f. From Band C Sc, Navy 
 island, St. John. See p. 217. 
 
 Fig. 3. Orthis Unticularis var. atrypoides — a Ventral valve ; — h Dorsal valve. Both 
 Mag f . From Band C 3c, Navy island, St. John. See p. 216. 
 
 Fig. 4. Orthis Unticularis var. strophomenoides — a Ventral valve ; — b Dorsal valve. 
 Both Mag. {. From Band C 3a, Germain St., St. John. See p. 217. 
 
 Fig. 5. Gtcnopyge pccten — a Middle piece of the head shield ; — b Pygidiam (After Lin- 
 narsson). Both Mag. f. The head from Band C 3c, at Escasonie shore. 
 East bay, N. S. See p. 229. 
 
 Fig. 6. Pardbolina Dawsoni — a Middle piece of head shield; — 6 Movable check; — c 
 A front joint of the thorax ; —d A pleura from the middle of the thorax ; — e The 
 hypostome ; — / The pygidium. All mag. }. From Band C 36. Escasonie 
 shore East bay, N.S. See p. 223. 
 
 Fig. 7. Sphcerophthalmus Fletcheri — a Middle piece of head shield ; 6 — Same from the 
 front ; — c Same from the sida ; — d Movable check ; — e Hypostome ; — / 
 Pygidium. All mag. f except e and f which are f . From Band C. 36, Escas- 
 onie shore. East bay, N. S. See p. 227. 
 
 Fig. 8. Agiwstus triscctus Salt. mut. ponepunctus — a Head shield ; — b Joint of the 
 thorax ; — c Pygidium. All mag. f. From Band C. 36. Escasonie shore, 
 East bay, N. S. See p. 220. 
 
19— C. K. 
 
PLATE XYIII. 
 
 Fig. 1. Acrotreta sipo. Section of the ventral valve, showing the siphon. See p. 185. 
 
 FlQ. 2. Acrotreta sipo. Interior of the dorsal valve, showing the median septum. Both 
 Mag. J, and from Absise C c^, McLeod brook, Boisdale, N. S. See p. 185. 
 
 Fig. 3. BeUerophon insulce — Sinistral side Mag. f. From Assize C So*, McLean 
 brook, Boisdale, N. S. See p. 217. 
 
 Fig. 4. BeUerophon Brctonensis — a Dextral side ; — b Broken valve, showing interior, 
 &c. Both natural size ; — e Dorsum, showing angle of the growth of lines. 
 Mag. I ; — d Part of surface of body waTl. Mag. f ■ All from Assise C Sc^. 
 McLeod brook, Boisdale, N. S. See p. 218. 
 
 Fig. 5. BeUerophon semiseulptus — Showing the outer whorl Mag. f. From Assise, 
 C 3c2, McLeod brook, Boisdale, N. S. See p. 219. 
 
 Fig. 6. Urotheea, sp. Tube, showing larval part and livmg chamber. From Assise, 
 3c2, McLeod brook, Boisdale, N. S. See p. 183. 
 
 Fig. 7. Parabolinella (?) quaoLrata — Middle piece of head-shield. Natural size. From 
 Assise C Sc*, McLeod brook, Boisdale, N. S. See p. 225. 
 
 Fig. 8. Triarthrus BelU — Middle piece of the headsbield, right side and occipital ring 
 restored. Mag. f. From Assise C 3c'', at McLeod brook, Boisdale, N. S. 
 Seep. 230. 
 
 Fig. 9. Angelina ? sp. — Larval cephalic shield. Mag. f. From Assise, C 3o*, McLeod 
 brook, Boisdale, N. S. See p. 232. 
 
 Fig. 10. AsapheUus Homfrayi, var. — a Adult, broad form, partly restored ; — 6 Middle 
 piece of the headshield of the narrow form ; — e The hypostome. All natural 
 size ; — d Early larval form. Mag. ^ ; — e A later larval form Mag. f . All 
 from Assise, C Sc^, at McLeod brook, Boisdale, N. S. See p. 232. 
 
 Fig. 11. AsapheUm (?) planus. Adult — Natural size ; — the pygidium enlarged from 
 another example supposed to be of this species. From Assise C Ze^, at Mc- 
 Leod brook, Boisdale, N. S. See p. 237. 
 
TREMADOC FAUNA. 
 
 Plate XVIII.