w. Y: irTwwMii^^mw.nr^i^==mn »^r -:^b:uSa3^, ■'r^'AA gm> \ r\ 'hi r\ /Aiss,-'' mRP^B if^^Or\: V ^L ^■^ -'^'^^ V"^ A ^«SrTM^AJAT^Ii^l^lo2UN»l^^ ^ ^ '*N l'.*^ ^ BOUGHT WITH THE INCOME FROM THE SAGE ENDOWMENT FUND THE GIFT OF X891 INGlNEERtNG LIBRARY A. CHAPTER v.* MIDDLE LIAS. The Middle Lias consists of two members, viz. ; — An upper series of ferruginous limestones called the Marl- stone Eock-bed. A lower series of shales and clays more ferruginous and arenaceous in the upper part. In Sheet 83 the boundary between the Lower and Middle Lias is rendered peculiarly indefinite by the great spread of Boulder Clay and sand at the foot of the Oolitic escarpment, north of Lincoln. The difference in the character of the Junction beds in Sheet 86 on the north, and in Sheet 70 on the south, tends to increase this uncertainty. In Sheet 70, as in Rutland, the junction has been inferentially taken as far as possible at the boundary between the zones of Ammonites capricornus and A. margaritatus, which are litho- logically indistinguishable. In Sheet 86, on the contrary, A. margaritatus has not been found, and A. capricornus makes its appearance at a few feet below the Rock-bed, and ranges downward to a ferruginous stratum about 60 feet below the Rock-bed, characterised by A. striatus and an abundance of Pectens, and called the Pecten Bed. A. capricornus occurs for some feet below the Pecten Bed, which has in Sheet 86 been taken as the base of the Middle Lias, being the first lithological horizon in the clays beneath the Marlstone Rock-bed. In the south part of Sheet 83 the evidence of the position of the boundary is derived from several pits in the neighbourhood of Lincoln, where A. capricornus and A. margaritatus have been found. In one of the most important of these, the Bracebridge Brick Co. 'a Pit, the lowest beds are characterised by the occurrence of numerous specimens of A. capricornus, and less frequently, of A. striatus. Prof. Judd (Geology of Rutland, p. 74) records the occurrence of A. capricornus in the Middle Lias Clays in one place. A. margaritatus has never been included in the Lower Lias, whereas A. capricornus occurs in the basement beds of the Middle Lias of Yorkshire. So that, should there be occasional evidences of a blending of these two forms, the presence of -4. margaritatus is much more conclusive than that of the commoner form, which, though locally zonal, often has an irregular and capricious range. From Navenby to North Carlton the boundary has been drawn in accordance with feature from Mr. Holloway's line in Sheet 70 northward, and with reference to the evidence obtained from the railway cutting near Coleby, the "Waddington and Bracebridge Brick-pits, and the pits near Lincoln Racecourse. * Written, except where otliciwise notecl, hy Mr. W. A. E, TlBsher. 24 THE LIAS. From North Carlton northward the boundary is rendered still more indefinite by a sheet of Chalky Boulder Clay, Pursuing the classification adopted in Sheet 86, the boundary of the Lower and Middle Lias has been taken as far below the Kock-bed as we conjecture the horizon of the Pecten Bed to be, tracing it southward from some indications of the bed on the north margin of Sheet 83 (W. long. 0° 36' 55"), and near Willoughton Grange. From its indefinite character the boundary between Middle and Lower Lias is shown on the map by a bi"oken line. In the southern part of Sheet 83 the Marlstone Rock-bed is absent ; it is last seen at the -village of Burton, and does not reappear for 12 miles, between that place and the village of Wellbourn, 2 miles south of the northern margin of Sheet 70. Near Wellingore in the northernmost part of Sheet 70 (vide Memoir on that Sheet) there is every reason to conclude that the Rock -bed is represented by from 12 to 15 feet of shales based on a hard bed with phosphatic nodules which contains numerous specimens of A. communis and is in all probability equivalent to, or on the same horizon with, the actual base of the Rock-bed. A. communis has been obtained from the Rock-bed north of Ingham ; but south of Burton it has not been noticed in the ferruginous nodular bands which occur in the upper clays of the Middle Lias. South of Burton the most marked horizon in the Middle Lias is a ferruginous nodular bed with phosphatic concretions, which is shown at about 20 feet below the base of the Upper Lias in the Bracebridge Brick Co.'s pit near Lincoln, and is so similar to a oand occupying an analogous position below the Marlstone Rock- bed at Gonerby, near Grantham, that Mr. Dalton was led to infer their identity. The persistence of the bed in the intermediate districts has not been proved, and it is evidently lower in the series than the bed at Wellingore. Mr. Dalton gives the following general description of the occurrence of this bed near Lincoln : — The lower member of the Middle Lias, otherwise called the zone of A. margaritatus, is composed of rather thinly laminated ferruginous shale, with bands of septaria and continuous seams of a stone containing almost enough oxide of iron to be termed ironstone, and which we may call iron-rock. This substance forms a bed three or four feet thick, portions of its base being crowded with phosphatic pebbles. The subjacent clays pass up by rapid alternations of thin iron-rock and shale of increasingly ferruginous character into the solid band. W. H. D. Both at Lincoln and Grantham, whilst specimens of A. margaritatus have been obtained beneath this ferruginous nodular band, no signs of that fossil were observed above it, so it seems to form the local upward limit of the zone or range of A. margaritatus. MIDDLE LIAS. 25 This circumstance, coupled with the prevalence of ferruginous nodules and, as a general rule, more arenaceous materials in the upper part of the Middle Lias clays, suggests a probability that the absence of the Marlstone Eock-bed may be due to its abnormal representation by about 20 feet of clay down to the ferruginous nodular band. But, if this is the case, and the Grantham bed on the horizon of that at Lincoln, we must also include in the Rock-bed series more than 20 feet of clay below the Eock-bed where it is not only present but well developed.* In the commencement of the following passage, Mr. Dalton seems to have admitted the possibility of the representation of the Rock-bed by clays in the districts where it is absent : — The Marlstone Rock-bed forming the zone of A. spinatus appears to be unrepresented, unless by clays inseparable from those below it, from Navenby to near Burton. Here it reappears, and, though thin, is continuous northward to the edge of the sheet. It has its usual character of a hard, somewhat ferruginous sandy limestone, sometimes crowded with fossils, sometimes with phosphatic pebbles and small water-worn slabs with indistinct casts of shells. The iron is sometimes in concretionary masses, but more generally diffused uniformly through the rock. W. H. D. From Fillingham northward, the junction of the Upper and Middle Lias is for the most part distinguishable by feature. The Rock- bed cropping out at the base of the Upper Lias slopes is exposed in section and evidenced by feature and surface soil between Fillingham and Glentworth, between Harpswell and Hemswell, and between Willoughton and the northern margin of Sheet 83. Between Glentworth and Harpswell the relations of the Upper and Middle Lias are rendered obscure by the presence of superficial deposits. Between Hemswell and Willoughton also, the geology is very obscure, and the position and extent of the Rock-bed very questionable. Middle Lias Clay. A cutting north of Navenby now grassed over only affords evidence of grey shaly clay in the drain at the base of the cutting. The cutting is about a quarter of a mile in length, thin brown ferruginous stone in grey shaly clay seems to have been got out at the signal-hut. Mr. Penning furnishes the following note on this locality : — A thin bed of nodular iron-rock is exposed in the railway cutting three- quarters of a mile north of Navenby Station. In the railway cutting west of Boothby Graffo a few inches of bro^yn iron-rock is exposed at the level of the rails, with blue clay above and below it. Similar beds are seen below Coleby. W. H. P. In ferruginous clay at a pond below Coleby Chemnitzia was obtained. The railway cutting west of the south end of Coleby village is 15 or 16 feet in the highest part. At its base a hard bed of impure micaceous limestone and * Professor Judd (Geology of Rutland, p. 75), describes a case similar to this. -6 THE LIAy. cement nodules, containing Goniomya v-scripta and numerous gasteropoda, is exposed ; above this, the cutting is grassed over. The following fossils were obtained from the hard bed by Mr. J. Bhodes, the Survey fossil collector : — Pecten liasinus, Nyst. Cardium truncatum. Sow. Cardita multicostata, Phil. Goniomya hyhrida, Miinst. Eucyclus imbricatus, Sow. Turbo cyolostoma, Benz. Ammonites margaritatus, Montf. Belemnites. Mr. Penning furnishes the following note : — In the old brickyard half a mile west of the south end of Waddington village, the beds consisted of — Grey marly clay - 2 ft. Iron -rock - - - - l^to2 feet. Bluish-grey shaly clay over 10 feet. The sand which covers the surface to a varying depth is washed down from the Northampton Sands on the escarpment above, and caught on the shelf of Middle Lias. W. H. P. This pit now exposes about 15 feet of grey shaly micaceous clay, with one or two bands of cement-stones, the largest being about 10 feet from the surface. Mr. H. B. Woodward obtained Goniomya v-scripta in a bed similar to that exposed at the base of the cutting west of Coleby, and occurring here at 4 or 5 feet from the surface. Mr. Woodward also obtained fragments of Ammonites margaritatus in the debris, showing the characteristic corded keel. The deepest sinking in the floor of the pit was full of water on the occasion of our visit (April 1885). We obtained Pecten cBrjuivalvis, Sow., in nodules in the clay in this pit. The following is from Mr. Dalton's notes : — Somewhat more than a mile to the north of Waddington Station is the pit of the Bracebridge Brick Co., extending from high in the Middle Lias down- ward, and probably reaching the upper beds of the Waddington Station pit. .\.s in the latter, the clays and their septaria arc highly fossiliferous. The Bracebridge Brick Co.'s pit has yielded the following measurements at different points : — \.—W. H. Penning. ^.— W. H. Bait on. Clays Interrupted iron-rock Grey marly clay Iron-rock with phosphatic nodules and iron pyrites and a thin clay bed at the base Grey shaly micaceous clay The heaps of septaria which are left on the floor of the pit between periodical removals may be distinguished by their colour, the yellowish grey from the lower beds being very distinct from the crimson and tawny masses from the shales above. Amongst the latter are some highly fossihferous slabs, and also masses of conglomerate of phosphate pebbles in a matrix of iron-rock. W. H. D. Since the above observations were made, the workings in the central face and southern side of the Bracebridge pit have been still further extended. Owing to the easterly dip of the beds, the highest beds are exposed in the central face of the pit, and are inaccessible for some feet from the surface, Pt. In. Ft. Ik, 5 Grey clays - - 17 6 Nodular iron-rock - ,'S C Shale with phosphatic pebbles 8 Iron-rock 2 4 Sandy shale 6 3 Iron-rock - 8 ^ 47 Ft. Ix, 4 C 3 MIDDLE LIAS. 27 whilst the lowest are shown in a sinking in the lloor of the pit on the west side and in its south-west face. The following observations were made in April 1885 :— Section on the north side of the Bracehridge pit. Grey shale - Ferruginous cement stone Grey shale ------ rSandy ferruginous clay and nodular stone, with I phosphatic concretions - - 1 Nodule bcd<^ Ferruginous nodular cement-stones stained I crimson on exterior, and mixed with arenaceous l_ shale - - - - 3 Grev micaceous shaly clay, often stained pale chrome, with bands of nodules, concealed by talus at base / - about 25 In the centre face of the pit nodular stone with phosphatic concretions and Belemnites occurs at the base of the nodule-bed. The uppermost bed in this place, where Mr. Dalton's section was probably taken, is now shown to be very ferruginous, suggesting a representative of, or approach to, Marlstone. Below the nodule-bed, about 30 feet of dark grey clunohy clay, splitting in thick shaly pieces, and containing nodules, was shown down to the floor of the pit in the central face. This clay contains many small Ammonites, too fragile for preservation ; Goniomya v-scripta was obtained from it at about 5 feet above the floor of the pit. In the south-west side of the pit dark grey clunchy clays, with round nodules containing many specimens of Ammonites capricornus, and less fre- quently, A. striatus, form the base of the section for about 10 feet upward from the floor. These clays are probably below the site at which Messrs. Rhodes and Maceonochie obtained Ammonites margaritatus in another and more central part of the pit, and are taken for 8 to 10 feet upward from the quarry floor, where the lowest beds are exposed, as Lower Lias {vide Notes on Lower Lias, p. 22). But as the range of A. capricornus is irregular, it is possible that that Ammonite might occur in abundance here in the basement beds of the Middle Lias, on a horizon en which it has been exceptionally found in Rutland. The clays here are used for the manufacture of bricks, drain-pipes, &c. The following is a list of the fossils obtained from the Bracebridge Brick Company's pit, or Clark's pit, 2i miles S.W. of Lincoln Cathedral, under the Nodule bed, by Messrs. Rhodes and Maceonochie : — Wood. Crinoid ossicle. Rhynchonella. Waldheimia perforata, Piette. Idma gigantea, Sow. L. pectinoides, Sow. Ostrea irregularis, Miinst. Pecten (Bqnivalvis ? Sow. *P. liasinus, Nyst. Cardium truncatum, Sow. Goniomya hybridal Miinst. fGresslya donaciformis, Phil. fG. intermedia. Simps. fG. Seebachii, Brauns. Hippopodium ponderosum, Sow. Leda, n. sp. L. graphica, Tate. *L. imbricata, S. and N. * Obtained in clay with septaria directly below the nodule-bed by Mr. Rhodes on a subsequent visit. f Obtained in clay near base of workings by Mr. Rhodes on a subsequent visit. 28 THE LIAS. Modiola scalprnm, Sow. Pholadomya. Pleuromya unioides, Rom. Unieardium cardioidesl Phil. Eucyclus imhricatus, Sow. Ammonites capricornus, Schloth.* fA. nitescens, Y. & B. '\A. margaritatus, Montf.t A. striafns, Rein.* Belemnites clavatus, Schloth. Bone, fragment. From the nodule bed in Bracebridge Brick Company's pit, Mr. Rhodes obtained the following : (a) denotes that the specimens to which it is prefixed were obtained in the nodules forming the upper part of the bed, and (b) distinguishes those from the ferruginous part of the stratum beneath : — Waldheimia perforata, Piette. a,Avicula cygnipes, Phil, a Ceromya liassica, Moore, a b Gresslya donaciformis, Phil. Plicatula spinosa, Sow. Pleuromya unioides, Rom. b Vnicardivm cardioides, Phil. Eucyclus imhricatus, Sow. Turio. b Ammonites margaritatus, Montf ., Young. aBelemnites vulgaris, Y. & B. At the further end of the village of Bracebridge is the deserted brickpit formerly worked by Messrs. Kirk and Parry. Here also the Middle Lias has from time to time yielded a somewhat varying section. Mr. Penning records the following particulars : — At the north end of the pit — Ft. Sand with ironstone concretions on an irregular surface of the clay below - - - - 3 Blue, very compact, shaly clay, with a three-inch band of non- calcareous flattened nodules and a thicker band of septaria about 10 feet below, some calcareous, others not so. There are a good many pbosphatic concretions in the clay, and some of the septaria exhibit a slickensided structure - - 18 At the south-east corner of the pit — Ft. Ins. Sand with a clayey base, fuU of hard flat lumps of calcareous grit - - - - 2 ft. to 3 Blue clay - - - - - - - 3 Band of iron-rock - - - 3 in. to 6 Blue clajr - ... 26 Band of iron-rock - - - - - 3 in. to 6 Blue clay - - - - - - 2 Yellowish-brown iron-rock, some of the concretions hard, others soft and ochreous - - - - - 2 The last bed throws out a spring ; it is 43 feet above sea level and dips at 3° to E. by N. W. H. P. The iron-rock at the base should be 2 feet 8 inches thick, and the s\ic- ceeding clay bands 1 foot 10 inches and 1 foot 6 inches respectively. W. H. D. * These and a, few more forms obtained in the lowest beds are included in the Lower Lias. f Obtained in clay near base of workings by Mr. Rhodes on a subsequent visit. J Ammonites margaritatus, got 3 feet above floor of Bracebridge pits by myself and Mr. A. Macconoohie. — John RiionES. Ft. 1 Ins. 6 4 1 6 4 8 3 18 MIDDLE IJAS. 29 In April 1885 the following section of the beds was e.xposed in Kirk and Parry's pit : — Surface, reddish-brown sand - ... Ferruginous rubble, suggesting a thin weathered representative of the Marlstone Rock-bed .... about Grey shale . - - - 3 ft. to Ferruginous septarian nodules - - . - - Grey shale - . - r Hard cement-stone nodules and ferruginous con- Nodule bed < cretionary bed with phosphatic concretions at L top and bottom ... about Grey shale, ferruginous in places, e.xposed down to water filUng the bottom of the pit, a thickness of . About 10 feet from the surface I obtained an Ammonite on the side of the pit, and at about 14 feet from the surface, a good-sized fragment of fossil wood in the clay. The nodule-bed in this pit is, doubtless, the same as that similarly denominated in the Bracebridge Brick Company's pit. The following is a list of fossils collected by Messrs. Rhodes and Macconochie from Kirk and Parry's pit, Bracebridge : — Wood. Crustacean fragment. Avicula cygnipes, Phil. A. iruBquivalvis, Sow. Inoceramus. Ostrea irregularis, Miinst. Pecten liasinus, Nyst. Astarte. Area Stricklandi, Tate. Cardium truneatum, Sow. Goniomya. Hippopodium. Leda imbricata, S. & N. L. graphica, Tate. Chemnitzia 1 Eucyclus imbricatus. Sow. Ammonites margaritatus, Montf. A. nitescens, Y. & B. A new road, called West Parade Road, was being made in the west part of Lincoln in April 1886. A drain running down the mi(Jdle of it showed bluish-grey micaceous clay, in places containing fragments of Belemnites, and friable specimens of small Ammonites. A list of fossils obtained by Mr. Rhodes is given below. In one place the drain was open to a depth of 8 feet, and ferruginous nodules were visible at 2 or 3 feet from the bottom. Drain in new road, Lincoln, to be called West Parade : — Wood. Ostrea. Lima. Pecten. Modiola scalprum, Sow. Eucyclus imbricatus, Sow. Ammonites margaritatus, Montf. Belemnites. Adjacent is Mr. Foster's old brickyard in which no exposure is visible. Plesiosaurus ? sp. was obtained from this pit by Mr. Fowler. The following notes are by Messrs. Dalton and Penning : — The septaria taken from Mr. Foster's old bi-ickyard, south of the Lincoln racecourse, are like those of the Bracebridge Brick Company's pit, and the section was probably on the same horizon. Mr. Penning records, under the usual covering of sand with ironstone debris, 15 feet of blue clay. No exposure is now visible. W. H. D. 30 THE LIAS. A little to the north of the racecourse is an old brickyard, formerly worked by Mr. Glasier, and though now somewhat obscured by talus, admitting of the following observations : — {Blue clay. Nodular ironstone, 6 to 9 inches. Grey shaly clay. Nodular ironstone with phosphatic pebbles. Blue clay, .9 feet. There is a perceptible dip to E. by N. W. H. P. For the new Gas Works in the south part of Lincoln, by the road to Bracebridge, a large pit had been sunk to a depth of about 20 feet, which is now walled round (April 1885). The refuse by the side consists of bluish- grey clay, with nodules, in which Mr. Rhodes obtained A. heterogenus, Y. & B. Between the Barracks, near Lincoln 'Mills, and the Race Ground, exceptional opportunities for observing the beds that crop out on the escarpment of the Inferior Oolite, on the north of Lincoln, are afforded by Swan's pit, in which about 90 feet of Upper Lias is exposed beneath the basement bed of the Inferior Oolite. From the bottom of Swan's pit, tram rails are laid for 6 or C chains downward across a feature suggestive of landslip. At and near the bottom of the tram, an arenaceous bed containing A. serpentinus is shown in shaly clays, belonging to lower beds in the Upper Lias than those exposed in the pit. The ground falls more gently from the bottom of the tram for 4 to 5 chains to the east end of Glasier's pit,- which affords a partial exposure of 15 feet of grey Middle Lias shales with ferruginous nodules. On the floor of the pit at 4 chains from the east end a ferruginous nodular band is shown (the same as the lower bed in Mr. Penning's section). From this point to the road where the pit terminates, a distance of 9 chains, the floor of the pit is some feet below the nodular band; bluish clay is evidenced, but no section exposed in this part of the pit. Mr. Rhodes obtained the following fossils from limestone nodules in tlie Middle Lias clay in Glasier's pit : — Crinoid stem and ossicles. Idngula. Avicula inaquivalvis, Sow. Pecten. Arcomya 1 Gardium. Goniomya. Gasteropod. Ammonites. Belemnites. From Willoughton Grange, northward, we obtain indications, slight, it may be, but relatively important, of the position of the Pecten Bed, which has been taken in Sheet 80 as the basement bed of the Middle Lias. In a ditch by the path from Willoughton Grange to Willough- ton indications of an ironstone bed were observed. At the northern border of Sheet 83 (W. Long. 0° 36' 55") signs of the outcrop of the Pecten Bed were noticed, in line with its strike in the southern parts of Sheet 86. With these two observations, solely, for our guidance, it is only possible to guess at the prolongation of the boundary line. Just south of Fillingham both the Rock-bed and underlying clay are concealed by Boiilder Clay, but from Fillingham Lake to Hems^^■ell a liand ^[IDDLE LIAS. 31 of Middle Lias Clay forms the surface at the foot of the feature made by the Rock-bed. This band attains its maximum width south of Glentworth , where the clay is exposed in a large disused brick-pit (a quarter of a mile south-west of Glentworth Church) : the section cousists of bluish-grey shaly clay with flat cake-like pieces of cement-stone and ferruginous concretions. In the ironstone nodules the fossil collector obtained Nueula and Actaonina, specifically indeterminable. Between Blyth Close and Harpswell stiff grey clay is exposed in a small pit on the Rock-bed feature ; it is either the Middle Lias Clay exposed through the denudation of the Rock-bed, or a drift-clay in association with the sand which obscures the relations of the beds in the vicinity. The next section in the clay band just below the Rock-bed is a brick-pit, now being worked, on the north side of the high road south of Hemswell, in which the uppermost part of the Middle Lias Clay consists of bluish grey shaly clay with cement-stone nodules, irregularj and partly ferruginous. This pit proved to be fossiliferous, the following specimens having been obtained from ironstone nodules in the clay : — Lima pectinoides. Sow. Cardium truncatum. Sow. Leda {n. sp.). Pleuromya. Ammonites. Belemnites. Although it was in the last degree important that the Ammonites in this list should be specifically determined, their unsatisfactory condition precluded it. The same disheartening remark applies to the greater part of the specimens obtained from the Lias beds generally in the northern part of Sheet 86. Great pains spent in discovering fossils in beds where their determination is in the highest degree important, but where their preservation is normally bad, have been thus rendered nugatory. In one part of the pit signs of the base of the overlying Rock-bed were noticed. The clay in the bottoms of the ditches between Hemswell and Willoughton may be in part Middle Lias, but the evidence is very unsatisfactory. Middle Lias Clay is evidenced at the surface by ponds and in ditches, just below the Rock-bed, between Willoughton and the Blyborough Valley : on the north of the Blyborough Valley it is concealed by Drift. In the road just north of Willoughton the clay is exposed belov/ the Rock-bed. Marlstone Rock-bed. Mr. Dalton observes : — Though the feature of the Marlstone is well marked, and fragments of it are seen at intervals between Burton and South Carlton, the first exposure of the actual rock in place is about 300 yards north of the church of the latter village. Here the denudation of the overlying clays has left the outcrop of the rock at a lower level than its base on the escarpment to the west, and a spring is the result. In the next field the path between the Carltons crosses a ditch showing the full thickness (about 6 feet) of the rock. Besides native fossils, the rock here contains many phosphatic pebbles and slightly- worn slabs of fossiliferous stone, in which, however, no determinable species were -found, though the outline of the casts suggested Cardinia and other Liassic genera. W. H. D. The following is a list of fossils obtained from the Marlstone Rock-bed in the ditch above mentioned : — Terebratula. Avicula. Gryphceal (fragment). Pecten eequivalvis, Sow. P. liasinus, Nyst. Lima, (fragment). Cardium^ (young) . C. truncntiim ? Sow. 32 THE LIAS. Cardinia crassiusoula, Stutch. Lithodomus. Unicardmm cardioides, Phil. Chemnit'da semitecta ? Tate = C. sublineatum, Moore. Pleurotomaria, fragment. Belemnites breviformis, Voltz. Mr. Dalton says : — Iq the little brook at North Carlton the base of the rock is seen, and close by is a small hole whence walling stone and road metal have been extracted ; the contained iron here forms numerous concretions constituting a large part of the mass. The rock is again seen at Aisthorpe, and at Cammeringham. W. H. D. The Rock-bed is exposed under Boulder Clay in the stream half a mile south of Fillingham and a mile and a half west of the Ermine Street near Ancholme Head. The following fossils were obtained from the ironstone : — Terebratula. Pecten substriatus, Rom. Cardinia Ldsteri, Stutch. Ammonites communis, Sow., two specimens. Belemnites. The Rock-bed is exposed at the surface in the village of Fillingham, and in a pit near the southernmost houses on the west, in which Terebratula punctata and Waldheimia perforata were obtained. At about 30 chains north of Fillingham Church, a small pit exposed 3 feet of brown stone, grey and crystalline in places, broken in the upper part, containing Belemnites ; the section is partly covered by 6 inches of soil with ferruginous fragments of the rook. In this tract, between Glentworth and Fillingham, the Rock-bed makes a considerable dip-slope, which may be masked in places by a Boulder Clay soil from 2 to 3 feet in thickness. The shaly ironstone is exposed in a ditch by the path between the villages to a depth of from 3 to 4 feet, at about half a mile from Glentworth. At a quarter of a mile, south of Glentworth, a foot of red-brown shaly ironstone was exposed under the roots of a tree. At Glentworth the Rock-bed is generally evidenced by red-brown con- cretionary fragments and small pieces of decomposed rock. Near HarpsweU on the south, the Rock-bed was visible, and its base was seen in the vicinity of the brick-pit, south of Hemswell. In Hemswell village, west of the church, the superficial extent of the Rock- bed is very doubtful, as, where the made-ground terminates, Boulder Clay commences, and there is no feature for the outcrop of the bed ; at the turning near the schoolhouse, beds which might be the Rock-bed in situ, were visible just below a section of Upper Lias exposed in draining. Between Hemswell and Willoughton the soil is sandy and loamy, and although there is some feature for the outcrop of the Rock-bed at its junction with the Upper Lias, its westward extension is unmarked by feature. In this tract at 64 chains from Willoughton Church, a short distance west of the blind road towards Hemswell, indications of the Rock-bed, in the form of rubbly ferruginous fragments on clay, were noticed by a pond. A few chains further north the Rock-bed is said to have been proved under about 3 feet of sandy Drift. If the sandy Drift of this tract is a modification of the outskirts of the Boulder Clay, largely due to the wearing away of the Rock- bed, it would be impossible to say how much of the bed had been spared beyond its line of outcrop, and its destruction would account for the absence of a line of feature on the west. Under the houses near the blacksmith's shop in Willoughton, brashy iron- stone is visible in situ. Ironstone is also evidenced at the most westerly Farm- house in Willoughton, and it is exposed by the road to Bly borough, just north of the stream at Willoughton. Between Willoughton and Blyborough, and north of Blyborough, the Rock-bed is evidenced by feature and surface indications. UPPEE LIAS. 33 CHAPTER VI.* UPPER LIAS. The following introductory notes on the Upper Lias are by Mr. Dalton :— The narrow belt of Upper Lias Clay in this district affords over the greater part of its length no sections, but in the neigh- bourhood of Lincoln the entire series is laid open in a single deep pit (that of Mr. Best at Bracebridge), and more than half of it in the pit on the North Cliff belonging to Messrs. Swan Bros, and Bourne. The only author who has described these instructive sections is Mr. W. D. Carr, who in 1883 communicated a short notice to the " Geological Magazine." To him is due the credit of detecting four out of the five zones into which the thicker series of Rutland has been divided by Professor Judd, the upper zone having been removed by denudation from this area : in fact, the transgressive overlap of the Inferior Oolite across the bedding planes of the Lias, can be detected by careful measurement, within the width of Messrs. Swan's pit.t The subdivisions remaining are as follows : — d. Black fissile shales with bands of ferruginous and calcareous nodules. Zone of Ammonites bifrons about 40 feet thick. c. Black shales with beds of comminuted shells, in which are many small whole gasteropoda and lamellibranchs, TV^onia pulohella and Nueula Hammeri being characteristic. The principal Ammonite is A. com- munis of which various modifications occur, but which in this area is confined to this zone, 8 feet thick. f b. Thick-bedded black and blue micaceous shales with bands of septaria and broken shell, the uppermost of the latter being characterized by an undescribed species of Lucina and by fine specimens of Belemnites subtenuis. The principal Ammonites are A. serpentinus and A. hetero- phyllus. 40 feet thick. a. Laminated black shales with two or three impersistent beds of argillaceous limestone, the " Fish-and-Insect Limestones," Dumbleton Beds (Prof. Judd). W. H. D. At Lincoln the Upper Lias seems to be about 100 feet in tlack- ness ; it probably attenuates northward to about half that thickness in Sheet 86. To the north of Fillingham the exposures are too few and insignificant to enable one to trace the horizons given above. A section of Harpswell Hill is given in " The Memoirs of William Smith," by J. Phillips, 8vo., London, p. 97. Blue Clays of the Upper Lias were exposed to a depth of 20 feet, * Written, except where otherwise noted, by Mr. W. A. E. Ussher. t Mr. Dalton's views as to the unconformity at the base of the Oolites, and as to the range of A. communis are not shared by rae. For all his statements respecting the position of Ammonite zones he is individually responsible. W. A. E. IT. i 50058. O 34 THTi; LIAS. In the brickyard half a mile east-north-east of Navenby Station, the following section, showing the so-called " Fish-and-Insect Limestones," was observed by Mr. W. H. Penning. Yellowish calcareous and sandy shale, the bedding planes crowded with Inoceramus duhius (fragments of the chitinous shell of which resemble scales of fish and elytra, &c. of insects) - - - - - - -1 foot. Grey shaly clay - - - - - 2 feet. Thin sandy dark-coloured limestone - - - 1 foot. Finely laminated shale - - - - 3 feet. Nodular bed with Ammonites. Shales - - - 2 feet. Thin sandy dark-coloured limestone. Paper shales. W. H. P. The section, as observed by Mr. Dalton in 1883, was somewhat different, viz. : — Ft. In. Limestone - - > . 10 Shales - - - - 4 8 Limestone - - - - - 4 Shales ... - 6 Ammonites annulatus, A. communis, Sfc. occur abundantly throughout. The following notes are also supplied by Mr. Dalton : — In an old brickyard below Coleby, the pit face, though much concealed by grass and talus, shows the shelly bed at the top of the A. communis belt. It. here contains very little comminuted shell, consisting principally of Pleuromyce, NuculcB, Ammonites, and Belemnites, closely packed in clay for about 8 inches in depth. The fine section of Mr. Best's brickyard fully atones for the scarcity of exposures southward. Here, as has already been mentioned, is a continuous section of the entire thickness of the Upper Lias. The Northampton Sand ironstone is seen to a thickness of 8 feet at the top, below which comes the following series : — Ft. In. Zone of A. hi/rons Clays - 37 9 Zone of A. communis Triaonia bed - 2 3 . Clay 5 8 'Lucina bed 2 Zone of Clay - - 1 2 A. serpentinus Shelly bed - 2 and ■> Clay - - 38 A. heterophyllus. Shelly bed - 1 6 _Shale - - 2 Zone of A. annulatus. ' Irregular concretionary limestone Shale - . Argillaceous laminated limestone - 1 . 5 1 6 Dark blue shales 12 110 The uppermost beds of the series are again seen in the road cutting west of Canwick, and in a pond below the workings of the Mid-Lincolnshire Iron Company between Greetwell and Lincoln. In the crumbling clay thrown out of this pond occur many crystals of selenite, probably originating from the combination of sulphuric acid in the clay with calcareous water percolating from the Oolite above. In the town of Lincoln the Upper Lias is only exposed occasionally in sewers and foundations, but about a mile to the northward, at the point where UPPER LIAS. 35 Lincoln Mills is engraved on the Map, Messrs, Swan Bros, and Bourne have a pit showing the following fine section : — Zone of A. bifrons. Zone of . communis. Zone of A. serpentinus and A. heierophyllus. Oolite limestone Ironstone Clays - . . • SheUy hed . Clays - . - . "Shelly bed, Trigonia or Nucula Ham men bed Shale. ■i Shelly bed Shale . - . - Shelly bed ^Shale . - . - "Shelly bed, Lucina bed Shale - . . - . Shelly bed j Shales ... I Double row of septaria in shales (. Shales - - - Ft. 8 4 22 1 4 2 1 1 1 10 In. 6 7 4 1 4 6 8 4 8 6 6 1 4 3 6 The full thickness of the Upper Lias at this point is 100 feet; the slope, from the floor of the pit to the flat marking the top of the Middle Lias, being 36 feet in height. The dip, which is to the north of east, will scarcely affect this measurement. The Lucina bed at one point was consolidated into a lenticular mass of limestone, unlike the septaria that abound in the shales, being of compact and crystalline texture. A pit was sunk in the floor of the brickyard to test the downward extent (!) of the clay; it was carried to a depth of 50 or 60 feet, ending in hard micaceous shale with a fissure full of foul air under pressure. It will be noticed that no mention is made of meeting either the limestones of Mr. Best's pit or the Marlstone Rock-bed of Burton, but either of these might be ignored by a sinker as merely septaria of unusual size, and the depth as well as the character of the lowest beds reached imply that the excavation ended in the Middle Lias Clays. W. H. D. From Fillingham northward the Upper Lias Clay can be traced with facility, owing to its position on the slope of the Clifl:, or Oolitic escarpment, beneath the basement beds of the Oolite, down to the flattish ground on which the Rock-bed of the Middle Lias crops out. The Upper Lias is nowhere exposed in continuous section, and the outcrop of the lower part of the division between Fillingham and Glentworth, and between Glentworth and Harpswell, is concealed by sandy soil, probably to a great extent derived from the waste of Lower Estuarine Beds. The lower part of the Upper Lias is similarly concealed between Hemswell and Willoughton and in Blyborough Park. The Upper Lias, where visible, consists of bluish-grey finely laminated shales. It is exposed by a pond just south of Harpswell ; in the roadside ditch in the north part of Hemswell Village, which is the most continuous of its exposures ; and by a pond near Willoughton on the north-east. No fossils were obtained from these exposures. C 2 36 THE LOWER OOLITES. CHAPTER VII.* THE LOWER OOLITES. Introductoey. The Lower Oolites in the area under description consist of seven members, bracketed into two main groups as follows : — p , rCornbrash. Q y, J Great Oolite Clay, o . I Great Oolite Limestone, I^Upper Estuarine Series. -r p . TLincolnshire Limestone. r\ y, -l Basement Beds : — consisting of the Lower Estuarine [_ Series and the Northampton Sand (Dogger). Of these divisions the Lincolnshire Limestone occupies by far the largest area in Sheet 83 : it rests on the Basement Beds at the crest of the escarpment (or the Cliff, as it is often called) whence the surface declines geatly to the foot of the low escarpment made by the Great Oolite Limestone resting on the softer beds of the Upper Estuarine Series. The Great Oolite Limestone, in its turn, occupies a surface falling gently eastward to the outcrop of the Great Oolite Clays, which form the outcrop slope of the low escarpment dominated by the Cornbrash. South of the Withara valley, at Washingbrough, the regularity of the features made by the members of the Great Oolite is inter- rupted in places by faults and obscured by superficial deposits. To the north of the Witham Valley the features of the Great Oolite divisions continue in almost unbroken succession. iNrERiOE Oolite. Basement Beds. The Basement Beds include the strata intervening between the lowest liraestones of the overlying beds and the Upper Lias Clays. These beds consist of the Northampton Sand and the overlying clays, shales, and sands of the Lower Estuarine Series. In the northern part of Sheet 83, where the Basement Beds begin to assume the types by which they are characterised in Sheet 86, the Northampton Sand is represented by a hard ferruginous bed called the Dogger, and the Lower Estuarine Series is overlain by a compact limestone bed, called the Hydraulic Limestone in Sheet 86 and included in the Basement Beds. In the northern part of Sheet 83, probably on the Escarpment above Hemswell, the Hydraulic Limestone either dies out or is represented by a bed or beds which do not present its distinctive charac- ters, and would, therefore, be included in the Lincolnshire Limestone. * Written, except where otherwise noted, by Mr. W. A. E. Ussher. INFEEIOR OOLITE. 37 The following observations on the Basement Beds are by Mr. Dalton :— The different names applied to this set of beds, viz., Northampton Sand; Lower Estuarine Series ; or Basement Beds — denote varying lithological characters, the first being applied to massive ironstone ; the second to clays and loams ; and, the third to the more hetero- geneous series in the northern part of the district. They are necessarily combined on the Map on account of their small development, and even so are barely capable of delineation upon the one-inch scale at points where the surface-slope is steep, although commercially the series is one of the most important in the district of Lincoln. These beds bear the ironstone facies, with occasionally a foot or two of grey clay at the top from Navenby to Burton, varying in thickness from 4 to 18 feet, and resting on an irregularly-eroded surface of the Lias clay, fossils and phosphatic nodules from which occur in a rolled and abraded condition in the lower beds of the ironstone. Between Burton and Ingham the clays and non-ferruginous sands prevail, to the partial or complete exclusion of the ironstone, the change being gradual, by intercalation of the valueless material and northerly attenuation of the several beds of ironstone. The reader is referred to Prof. Judd's memoir on Sheet 64 for a full account of the structure, composition, and probable origin of this interesting rock.* Analyses of the Ironstone of the Northampton Sand. A. B. c. D. E. Peroxide of iron 58 '06 38-18 30-83 37-00 44-13 Protoxide of manganese 0-02 0-03 0-03 — 0-30 Alumina 6-10 7-00 a-48 4-00 5-73 Lime - - ... 2-94 2-20 2-91 14-25 4-06 Magnesia 0-89 Trace Trace — 0-33 Silica - - 13-17 38-10 51-14 21-00 23-61 Sulphur - - - Trace 0-02 0-02 — 0-43 Pliosphorie acid 0-80 1-62 0-69 — 1-39 Carbonic acid 1-87 ■ 20-00 ]-12-40 J 7-50 Water, combined „ hygroscopic 11-86 4-29 [■13-05 12-20 |3-75 Total 100-00 100'20 100-30 100-00 99-93 Metallic iron, per cent. 40-5 26-73 21-58 26- „ in samples as received - — — — 31-45 „ in calcined stone — — — 38-57 A. Very rich nodule of Waddington Red Ore. ^ B. Average of lower bed of same. 'i C. „ upper „ ( D. Coleby Blue Ore. J E. Lincoln, by J. Pattinson, in Messrs. Daglish and Howse's paper. — Trans. N. Engl, Inst. Eng., vol. xxiv., pp. 23-33 [1875]. From Capt. J. G. Macdakin (by letter). The Geology of Rutland (Geol. Survey Memoir), 1875, pp. 90-138. 88 THE LOWER OOLITES. E. was dried at 212°, losing 7 '6 per cent, of hjrgroscopic water. For com- parison with the other analyses, the percentages given have been reduced in the same proportion. ^ W. H. D. To the north of lagham, the Basement Beds are better developed in Sheet 83 than in Sheet 86, although we cannot obtain indica- tions of an individual limesf one for the top resembling the Hydraulic Limestone, except in the northernmost part of 83, near Willoughton Mill, and to the north of it. The Basement Beds north of Ingham consist of — r Sands partly cemented into ' pan ' Lower Estuarine Series -| and irregularly associated with (_ dark grej clay. Dogger - - Hard brownish sandstone. Southward of Coleby the ironstone was worked for a time from a section, showing the following divisions, as noted by Mr. Penning : — Ft. In. Fine-grained oolitic limestone - .-50 Sandy ferruginous limestone, partially converted into ironstone - - - - - 1 6 Sandy clay - - - - .09 Ironstone - - - - - 6 Blue Lias clay ...... The dip here is southward at about 2°. The following section of these beds is given by Capt. Macdakin* of a shaft sunk at Coleby : — Ft. In. Oolitic limestone - - 36 - "Peroxide bed - - - - - „ 8 Clay ironstone - - - - „ 4 Hard carbonate of iron - - - >, 9 Clay parting - - „ 4 Hard blue carbonate of iron - - - 1 4 Peroxidised band - - - - „ 10 Nodules and clay partings - - - „ 1 1 Blue ferruginous sand bed - - 1 1 Ironstone nodules - - - - „ 6 Clay with nodules (micaceous) - - 3 Coprolites and pyrites - - - - „ 3 Blue Lias clay . . . - " The ironstone beds vary in richness and in their mineral characteristics ; whilst the upper beds are siliceous, the lower beds are more argillaceous. Some of the richer bands contain as much as 40 per cent, of iron, which in the more siliceous portions falls to 28 per cent. The ore near the outcrop occurs in nodular masses on an average, perhaps, of a foot in diameter, some- times as geodes with concentric bands of oxidation, and occasionally containing a loose kernel of unoxidised blue carbonate of iron. For 200 yards from the outcrop, the beds are of a deep reddish-brown colour; then changing into the bluish-grey carbonates ; the red ore occasionally lining fissures plainly showing the cause of this change from the original blue carbonate by oxidation to the brown clay ironstone nodules of the outcrop, which even still, in some places, exhibit on fracture a centre of the original blue carbonate of iron. Some portions of the peroxidised beds are very vesicular, the wellsinkers having from time immemorial called it ' Firestone,' believing it to have been the work of subterranean fires." * Geological Magazine, DoQ. ii., vol iv., pp. 406-410. (1877.) gT3 INFEBIOU OOLITJ;;, 39 Mr. Penning remarks that : — the ironstone was at one time worked on the north of Waddington, almost due east of the station. Here, under 5 or 6 feet of thin-bedded Oolite, was a bed of finely laminated clayey sand, from 12 to 18 inches in thickness, resting on concretionary ironstone 9 feet thick. In the blue clay below, a discontinuous nodular band of ironstone, or ferru- ginous septaria, was observed at about a foot from the uj^per limit of the clay. At Bracebridge eight feet of ironstone is seen at the top of Mr. Best's brick pit, resting on the Lias, and a pond on the west side of the high road, opposite White Hall, shows a foot of yellow sandstone over a foot of light- mauve -coloured sand, both containing plant-markings. Three furlongs west by north of Sheepwash, or three-quarters of a mile east by north of Oanwick, the ironstone is exposed in the following section : — Ft. In. Rubbly limestone - - - - -30 Brown sand, clayey at base - 6 Ironstone ... . go W. H. P. The following observations are made by Messrs. Dalton and Penning : — The raiWvay-cutting south-west of Washingbrough crosses obliquely two slight undulations of the beds, producing two artificial inliers in the floor of the cutting. The eastern inlier runs" from the bridge a quarter of a mile south- west of WashingBrough church for 280 yards to the north-west ; of this, 200 yards is composed of ironstone in contact with the Oolite on the south, and 130 yards on fhe north side of the line, four feet of the ironstone being seen at the highest point. At the extreme east of the inlier, 23 inches of clay separates the ironstone from the Oolite above. The western end of this inlier consists of grey clay for 80 yards on the south, and 160 yards on the north side. An interval of 120 yards separates this from the western inlier 200 yards long, and rising 3 feet above the rails, all clay. A little more than a mile E.N.E. of the Cathedral a number of strong springs rise in a tiny combe about 200 yards south of the Wragby road. The sides of this hollow have lately, 1884, been proved to consist of ironstone, as was previously suspected. Fragments of this rock occur in the soil to within 40 yards of the road, on the west of the fault which brings up the Lias to produce these springs. Half a mile to the south-east is an extensive open- wgrk belonging to the Mid- Lincolnshire Iron Company. Here 16 feet of ironstone, mostly peroxidised, but partly blue- or green- hearted, is quarried into a tramway, extending along the floor of a trench, of which one side is the unmoved ore, with a capping of 10 to 12 feet of oolitic rubble, the other a bank of the same rubj)le, rising to the level of the top of the ironstone. Successive widths of j;he ore. are cleared of the capping, which is carried on planks across the trench, which is then moved to the west by the quarrying away of the shelf of ore. Though the ground rises westward, the rise of the beds is for the present so nearly equal, that the capping is not increasing in depth as the work proceeds, whilst further up the hill the ore has been reached by tunnel-mining, and considerable areas have been worked out, and the overlying rock allowed to fall in by the removal of the timbering. The lower 2 feet of the ironstone is so crowded with phosphatic nodules as to be worthless for smelting, whilst its hardness has deterred the makers of phosphatic manures from attempting to utilize it as a source of phosphoric acid, although by weathering the ferruginous matrix soon breaks up and frees the nodules . In the road below the workings, and about 100 yards west of the brook, is seen a breccia of angular fragments of ironstone and oolite in a fine calca- reous paste. This is the fault-rock of the fault before referred to, which throws down the Oolite on the east, and by bringing it into juxtaposition with the Lias on the west, has presented the line of weakness now represented by a side valley practically along the fault. South of the road are minor open-works under the same owners, and the entrances to the tunnel-mines range all along the escarpment nearly to the Hospital. The aspect" of the face of ironstone varies much from local causes. The blue or green nuclei are sometimes very large, extending to within a few 40 THE LOWER 9OLITES. inches of a joint- or bedding- plane ; at other times they are absent altogether, the rook being peroxidised throughout. Sometimes the cellular structure is strongly pronounced ; other portions being nearly homogeneous. A bed of grey clay, varying from a foot thick down to nothing, separates the ironstone from the Oolite, and calcareous infiltrations from the latter sometimes coat the ioint faces of the ironstone with tufaceous films. W. H. D. The ironstone has been proved by boring to continue eastwards, but is not at present worked, having 65 feet of Oolite above it. One of the minor open-works mentioned above shows the following section : — Feet. Brown sandy loam, full of broken ironstone - 8 Brown sandy loam, without ironstone - 2 Grey clay, with many phosphatio nodules - 1 Dark blue clay (Lias). The Monks' Abbey Quarry, on the escarpment north-east of the ruins, shows the following beds : — Feet. Rubble - - - - 3 Thin-bedded limestone - • - - 4 Hard sandy limestone - - - 1 Marl - - - - 1 Compact ironstone - - - - 8 W. H, P. It is uncertain whether these accounts refer to sections still open, as in the progress of the works exposures are perpetually obliterated and replaced by fresh cuttings. Bight feet of good ironstone may be seen at the north-east corner of the Arboretum, and the rook has been exposed in sewers and foundations, everywhere through the town to the Union. W. H. D. Under the cricket field on the Wragby road, the Oolite cap is 45 feet thick, and the ironstone 6 feet, all blue stone. In the large clay pit on the north cliff, belonging to Messrs. Swan Brothers and Bourne, the following series of beds is seen above the Lias Clay (which has already been described, p. 35). Feet. Rubbly limestone - - - - 4 Hard limestone - .... 1 'Ironstone with a few phosphatic nodules and derivative fossils, sandy ,T , , . at base in places - » - 2 or 3 Northarnpton ^ ^j^^ intermittent bands of light sanas. j mauve-coloured clay. I Ironstone, crowded with phosphatio [_ nodules. Blue Lias clay. The pale mauve or violet clay, here interbedded with the ironstone, expands northwards to a thickness of, possibly, 20 feet at Burton. In the by-road leading to an Oolite quarry, due east of Burton church, light mauve-coloured clay and loam are seen to pass under ironstone, 1 foot thick. At another point in the road the following section is seen : — Limestone. Ferruginous sands, about 6 inches. Ironstone. Violet-coloured loam. At the spring, north of Burton Mill, ironstone is seen to a thickness of 6 feet, though possibly there may be a little slipping of the hillside at this INFERIOR OOLITE. 41 point, and the rock seen may be out of its true position. The uppermost part of this series is exposed in a small quarry above this, showing — Feet. Lincolnshire / Rubbly limestone - - 3 Limestone 1. Grey, slightly oolitic limestone - 2 Lower Estuarine clay, with nodules of ironstone. At the braneh roads south-east of South Carlton, violet-coloured loam is seen in the road-cutting ; ironstone is exposed above this. W. H. P. The loamy sands have been dug above Cammeringham. W. H. D. From Ingham Heath northward to Glentworth, the position of the Basement Beds is sufficiently well indicated without actual exposure, by the steeper upper part of the escarpment slope, by occasional sandstone fragments on the surface, and by ponds in the underlying Upper Lias Clay. The upper boundary, owing to the presumable absence of the Hydraulic Limestone, is not so certain, but the uppermost bed of the Lower Estuarine Series sufficiently indicates its position. The turning to Glentworth shows the following section under hard lime- stone, partially exposed : — Ft. In. Grey loam and clay, with ironstone nodules in the upper part - - - - - Yellowish and bufE sand, with greyish seams, about Grey clay, apparently on grey moist sand, both together being about - . . . Grey loam and sand, partly indurated, containing ligneous matter - . . . . Yellowish, buff, and whitish mottled sand, about This would give an exposed thickness of 10 feet to the Lower Estuarine Series, and as the Upper Lias appears to be about 10 feet, or more, below, it is probable that the Basement Beds are from 20 to 25 feet thick. A soil of buff clay with bits of limestone, about a foot in thickness, rests upon the outcrop of the upper bed, and upon the outcrops of the succeeding beds brown sand and gravel patches are visible. In the late Professor J. Phillips' Memoirs of William Smith, p. 97, a section of the Oolitic escarpment at Harpswell, as recorded by the latter, is given. It is probable that the great thickness of beds between the 20 feet of Upper Lias, exposed, and the Lincolnshire Limestone, was assigned to them from observations made in neighbouring localities, and not in one successive exposure, as we have no evidence of a greater thickness of Basement Beds than 30 feet in this neighbourhood. The section is as follows : — Feet. I. White limestone (oolite) - - 30 k. Whitish clay and sand - - - 12 i. White sand - - - 3 h. Sandy with iron balls - - - 10 g. White micaceous sand - '3 /. Brown sands - - - - 4 e. Clay parting. d. Brown sandstones and shells • - SO c. Blue clays, 20 feet exposed. b. Marlstone Series. a. Lias Clays. 1 6 2 2 6 2 2 42 THE LOWEK OOLITEii. No doubt the road cuttings presented greater facilities for observation when the above section was taken, and the lithological descriptions are valuable : — c. represents a part of the Upper Lias. d. is the Dogger, or representative of the Northampton Ironstone, its thickness as applied to this district is enormously exaggerated. e. to k. inclusive, show the composition of the Lower Estuarine beds. I. is the lower part of the Lincolnshire Limestone. The estimate of the thickness of I. being evidently a general one, the thicknesses of the subjacent beds cannot be taken as absolute. By the high road on the north of Harpswell, beds of soft bufi micaceous sand-rock, split up by numerous joints, and shaly in places, are exposed to a depth of 5 feet, and are also shown in a small pit adjacent. The beds may have a dip to the east of 2°, but this is uncertain. There are indications of Upper Lias Clay in the road at about 6 feet below the sandstone exposures. In a farmyard by Harpswell church, about 10 feet of similar buff sand-rock, apparently dipping in an easterly direction, is exposed by a pond ; above it there is evidence of grey and buff loam. By the turning to Hems well the Lower Estuarine beds are partially exposed. They consist of grey clay with a violet.tinge and shaly tendency, upon yellowish sand and sandy loam, with brown and buffi sand-rock or sandstone, broken and more or less nodular. The best section of these beds is afforded by the exposure at Heraswell well, where yellowish-brown ferruginous sands, occasionally associated with clayey matter, about 15 feet thick, would appear to constitute the Lower Estuarine Series, the Dogger below it being from 10 to 15 feet thick, and composed as far as visible of — Ft. In. Pale grey and yellowish, tough, siliceous rock, with lateral joints or bedding lines in places, about - 1 6 On beds of softer material, with ochreous brown fos- siliferous matter - - - - 2 Upon yellowish-brown, tough, friable, bedded sand- rock, alout - . . . - 5 The base cannot be far beneath the last-mentioned bed the point at which the water issues. There may be 2 feet of Dogger above the uppermost bed. To the north of Willoughton Mill the Basement Beds occupy a considerable area, but it is not possible to separate the Dogger, which may be from 1 5 to 20 feet thick, from the Lower Estuarine Series. The Lower Estuarine beds appear to contain much clay in their upper portion, partially exposed by the sides of ponds. In this district, also, fragments of what, in Sheet 86, we should call Hydraulic Limestone, occur on the surface, although no Hydraulic Limestone is exposed in section, unless represented by a hard greyish-brown siliceous limestone observed in a ditch. We have felt justified in separating the capping bed of a hill, extending southward toward the letter h of the word Willoughton on the Map, from the Lower Estuarine beds beneath, and from beds of the Raventhorpe, Low Santon, and Winterton types (i.e., beds above the Hydraulic Limestone in Sheet 86) above ; but these lines for the representative of the Hydraulic Limestone cannot be drawn beyond a point about half way between Willoughton and Hemswell; the Lower Estuarine beds consist of grey clay and white and yellowish sand, as far as their composition is observable. In Blyborough Park the Dogger is exposed in the plantation, and portions of it have also been noticed in the roots of trees blown down in the Park, after severe gales. It consists of soft, brown, broken, ferruginous sandstone, very rubbly. As far as one can judge from ponds on the south of, and near the letter h of the word Blyborough on the Map, the Lower Estuarine beds consist of whitish sand and clay. Between Willoughton and the northern margin of Sheet 83, miich of the Upper Lias slope is concealed by sand, probably ddbris from the Dogger and Lower Estuarine beds, the arenaceous character of these beds will also perhaps account for sands obscuring the lower part of the Oolitic escarpment between Willoughton and Hsmswell, between Harpswell and Glentworth, and on the north of Fillingham. INrEKIOR OOLIT];. 43 The Lincolnshire Limestone. From the great superficial breadth of the Lincolnshire Lime- stone area, south of Lincoln, it has been found convenient to describe the sections on the west of the Roman Koad first, and then those which lie to the east of it. The same valuable topo- graphical landmark has been similarly used as far as Mr. Dalton's area extends north-ward, i.e., to Ancholme Head. To the north of Anoholme Head the breadth of the Lincolnshire Limestone becomes less, and so small a part of its surface lies to the east of the Roman l{oad, that the continuation of this method of descrip- tion is no longer desirable. It is to the north of Ancholme Head that the variability of the Lincolnshire Limestone first assumes a stratigraphical significance, which in Sheet 86 on the north is so marked as to enable us to divide it into an Upper and Lower group. Near Washingbrough Mr. Dalton assigns a thickness of about 65 feet to the Lincolnshire Limestone, it may attenuate from Lincoln northward, but the exposures toward the north margin of the map are too shallow and scattered to permit of a reliable estimate. Mr. Dalton observes: — The Lincolnshire Limestone is the only member of the Oolite series in these parts that exhibits oolitic structure, and it does so in great variety, ranging from a congeries of barely perceptible grains to what at first sight appears to be a conglomerate with pebbles reaching nearly an inch in length, but which prove to be merely calcareous concretions, similar in all but size to the granules of the normal oolite. Again, there is every gradation from a rock entirely oolitic to one which shows no such structure, the granules occurring more and more sparingly in the amorphous matrix. Within the area of drainage of the Witham, these lithological variations appear to have no stratigraphical value, the secondary action which has produced the oolitic structure having affected beds at every horizon throughout the mass, omitting portions here and there in an apparently capricious manner. In our present ignorance of the conditions favouring or retarding this structural change in originally amorphous rock, we can only speculate on the possible effect, on matter of varying porosity and charged with water of varying composition, of the pressure and corresponding rise of temperature to which, from independent evidence, we know that these beds have been subjected. W. H. D. In the area from Ancholme Head northwards, the Lincolnshire Limestone is not homogeneous, but it would be useless to draw boundary lines for the lithological variations displayed by the beds, although as we approach the northern margin of the Map, these lithological horizons fall more or less clearly into strati- graphical groups. In the survey of this area, lithological lines of demarcation were drawn, as far as practicable, with the view of ascertaining the lie and relative thicknesses of the component parts of the Lincolnshire Limestone, but it was found inexpedient to u THE LOWER OOLITES. transfer them for publication, as there is no strong contrast between the lithological varieties of the beds comparable with that displayed by the upper (Ponton) and lower (Kirton) beds of the Lincolnshire Limestone in Sheet 86, on the north. The components of these lithological groups exhibit the following succession, subject of course to local variation, in the north part of Sheet 83. Lincolnshire Limestone. . Grey limestones. Semi-oolitic beds. Hydraulic Limestone ■< series. In many respects resembling the limestones of the Kirton Beds in Sheet 86. Whitish, cream-coloured, and buff limestones, with oolitic grains here and there. In their lower part these beds appear to be interstratified with nodular argil- laceous limestone, and hard, somewhat siliceous, limestone in places. "Hard grey limestones weathering brown. These beds probably represent the Hydraulic Lime- stone, and the beds above it, which are seen at Raventhorpe, in Low Santon road-cutting, and in the district between Winterton and Roxby (localities in Sheet 86). The semi-oolitic beds appear to be in their upper part on the horizon of, probably, the lower beds of the Ponton Series in Sheet 86 ; the cream-coloured beds are often very like beds in the Ponton Series in the southern part of Sheet 86. The overlying grey limestones, which cannot be traced for more than a mile or two into Sheet 86, are either upon the horizon of the upper beds of the Ponton Series, or in its northerly attenuation this uppermost member of the Lincolnshire Tjimestone dies out. The lower part of the semi-oolitic beds together with the Hydraulic Limestone series, may be said to occupy the same position as the Kirton Beds, nor is the passage of the one into the other remarkable, when we consider the impersistent character of the component loams, clays, and limestones in the typical Kirton Beds, and the development of coarse buff oolitic beds, and of arenaceous or siliceous limestones toward their base. The beds which we have called the Hydraulic Limestone series, ought of course, if that title were significant, to be embraced in the Base- ment Beds, but this cannot be done, as these beds, usually characterised by more dwarfed forms of life, have not been alto- gether included in the basement series in Sheet 86, but a distinctive hard bed at or near their base called the Hydraulic Limestone, was so taken, and that bed has not been detected in Sheet 83, although mention of beds of somewhat similar character will be found in the detailed notes. INFERIOR OOLITE. 45 Between Caenby Corner, Harpswell, and Hemswell, the semi- oolitic beds exhibit very indefinite characters, being in part com- posed of grey and bufF arenaceous limesfone, and in part of pale grey and whitish impure nodular limestone, in which the oolitic character is either absent or inappreciable. The hard beds seem to be interstratified with the more rubbly materials. These characters were exhibited in a quarry recently filled up, on the top of the hill above Hemswell, and by the high road near Harpswell, in the direction of Caenby Corner. I. South of Lincoln. The following notes are by Messrs. Penning and Dalton : — The simplest method of describing the various sections of the Lincolnshire Limestone in the wide area south of Lincoln, will be to accept the arbitrary boundary furnished by the Lincoln and Sleaford high road, and take first the western and then the eastern parts of the area thus divided. Occasional seams and partings of calcareous shale, crowded with minute fossils, are seen in quarries and railway cuttings, but these never produce any feature beyond the limits of the sections exposing them, and cannot be traced with any certainty from section to section. A glance at the Map shows a series of villages along the escarpment of the Oolite, and a similar series on or near the less regular line of its outcrop, Branston being the only village not conforming to this rule, which arises from the all-important condition of water supply. That requisite of life is readily oblainable on either side of the tract of open porous limestone in which it is supported on the west by the impervious Lias clay, and on the east by the absence of means of escape, the rock being waterlogged up to the lip of overlying clay and overflowing in powerful springs. Fig. 1. Diagram-section of the Oolite plain south of Lincoln. Villages. Villages. A. Lias. B. Inferior Oolite. C. Great Oolite Series.. D, D, D, Line of perennial saturation, with springs at points of intersection with surface. W. H. D. a. Western side of the Oolite plain. An old quarry about a mile and a half east by north of Navenby shows 10 feet of fissile Oolite, and abouta quarter of a mile north of this the following section is seen in another quarry : — Ft. Rubbly limestone - - - - - 3 Grey clay - - - . - _ - 1 Creamy oolitic limestone in five beds with thin clay partings - - - - - - 6 46 THE LOWER OOLITES. East of the church at Boothby GrafBo is a quarry showing several clay beds separating the beds of oolitic limestone, thus : — Ft. In. Rubbly limestone - - - .60 "Clay - - - - - 6 Oolite - - - 5 Clay - 6 Oolite 16 Clay, thin irregular bed - - - — Creamy limestone - - - 1 6 Thick-bedded oolite - - - - 6 Eastward of Harmston Church the Oolite is raised In a quarry showing the following beds : — Rubble, passing down with undisturbed oolite Shelly clay - . - . - Oolitic limestones .... Creamy oolite with clay partings Brown clay . - - . - Massive oolitic limestone Half a mile north of this a shallow excavation shows, under three or four feet of rubble, two feet of hard, fine-grained, cream-coloured limestone underlaid by rock of the normal oolitic character. A quarter of a mile north-east of Waddington a quarry shows the following divisions : — Ft. In. Ft. In. 5 6 1 6 6 2 3 Rubbly limestone . 6 to 8 White marly limestone, slightly oolitic 2 Grey clay - . - - . 9 Marly limestone, slightly oolitic 1 n Good oolite .... 5 A small exposure of thin-bedded limestone [(the flakes averaging an inch through) was seen in 1878 half a mile west by south of St. John's Heath. In a quarry a quarter of a mile south-east of Red Hall, Bracebridge, 4 feet of rubble overlies 7 feet of oolitic limestone in beds from 6 inches to a foot thick with partings, sometimes 3 inches in thickness, of shelly clay or shale. W. H. P. b. Eastern side of the Oolite plain. Outside the village of Scopwick, on the north-west side, are some large quarries affording typical sections of the Lincolnshire Limestone, and the course of the fault, which here bounds the area of this rock, is easily traceable by the soil, clayey and with fragments of non-oolitic ragstone on the east, sandy with oolite fragments on the west. W. H. D. An old quarry about a mile west by north of Scopwick shows 10 feet of fine sandy false-bedded limestone under 5 or 6 feet of rubble. Half a mile to the west of this, coarse oolitic limestone, of a pinkish tint, is exposed in a quarry about 11 feet deep, of which rubble forms the upper 4 feet. The dip here is to east by north at 5°. North of Scopwick Lodge fine-grained slightly oolitic limestone is quarried to a depth of 10 feet under 4 feet of rubble. In a quarry half a mile south-west of Blankney the limestones are worked to a depth of about 20 feet. The beds are somewhat thin and vary in texture from hard creamy stone, used in building, to soft rock only fit for lime. In another pit near by, at a lower level (now disused), the bottom beds are sandy limestone. W. H. P. The Oolite is seen under gravel half a mile south-east of Blankney Hall. Between this and Metheringham rise some fine springs. W. H. D. INFBRIOK OOLITE. 47 The following section is exposed in a quarry half a mile west of Metheringham : — Ft. In. Rainvvash and rubble - - - - 5 Fissile, coarse, brown oolitic limestone - - 3 0' Massive whitish limestone - - - - 2 6 Blue limestone ... - 1 Grey shale with ooliths - - - -36 Hard oolitic limestone with Nerincsa, &c. - - 4 Coarse brown sandy limestone - - - 2 A quarter of a mile to the north-west of this a quarry on the south side of the road shows the following series of beds : — Ft. Fissile limestones - - - - -4 Coarse yellowish sandy oolitic limestone - - 2 Very coarse false-bedded sandy oolite crowded with fossil shells, corals, &c. - - - - - 2 Fine-grained sandy oolite in thin beds - - -8 A short distance south-west of Great Spring Head is a small quarry showing at the top some three feet of thin-bedded limestone of very typical oolitic structure ; beneath this more sandy beds occur, passing down into coarser oolite. The springs here issue in copious flow from fissures in fine-grained sandy limestone, the upper part of which is here and there of a pinkish-yellow tint. A little south of Dunston Station a small quarry shows the following divisions : — Ft. In. Rubbly limestones - . - 3 Marl with bands of chalky rock - - - 2 6 Coarse oolitic, pinkish limestone - 4 Marl with ooliths - - - - - 1 6 Coarse oolitic limestone - - - - 2 Finer ditto - - - 2 In a somewhat obscure section, about a mile and a half west of Dunston, the following beds are seen : — Ft. In. Chalky-looking limestone and rubble - - — Pink sandy limestone - - - (i Clay with chalky rock - - - 2 Oolitic limestone - ' - - - 5 Grey clay - - - - - - 1 6 Oolitic limestone - - - - . — Half a mile to the west of this a quarry by a farm shows about 16 feet of rook, as follows : — Rubbly limestone - . . . . Chalky limestone - - - . White rubbly chalky limestone, with clay bands below Fine oolitic limestone - - . . Soft yellow creamy limestone Marl - ' ■ - . . Hard thick-bedded oolitic limestone In the goods yard at Dunston Station a glaciated floor of limestone was laid bare under the Boulder Clay in 1882. This was partly quarried away and partly left with a protecting coyer of Boulder Clay several inches thick, under the broken stone with which the yard is "metalled" in the neighbourhood of the goods shed. The rise of the rock surface to the west necessitated its being cut back, but the section thus formed presents no points of interest. Imme- diately north of the station, however, the line enters a very fine cutting, nearly 40 feet deep at one point, and showing at least four small faults which in general are very oblique to the faces of the section. At the north end of the Ft. In, 2 1 4 1 6 I 6 6 6 W. H. P. «o THE LOWER OOLITES. up (or eastern) platform is seen the base of the Upper Estuarine Series resting on the topmost beds of the limestone ; the beds rise sharply to the north, and at 60 yards beyond the bridge (as measured along the centre of the railway) are thrown up 7 feet or more by a fault trending E. 2° S., and hading south- ward at 60° to the horizon. There appears to be a second fault, with a north- easterly downthrow, running from where the first fault crosses the centre of the railway, in a direction S. 39° E. towards the station, disappearing from sight in the western span of the bridge. On the western or up-throw side of this is seen a bed of dark sandy bituminous and marly shale, rising northwards from the floor of the cutting to about 13 feet above it at the first fault, beyond which it is about 20 feet above the rails. Below this shale band are several minor partings, thus : — Ft. In. Limestone - - - - 15 to 20 Shale band 3 Limestone - - - - - -60 Shale - . . . 3 Sandy limestone - . - 6 Shale 3 Limestone - - . . - 6 3 Shale 3 At 150 yards from the " first " fault is the third, trending E. 27° S., and, like the first, throwing up the beds to the northward. Nearly due west of Nooton Lodge a huge coral 6 feet in diameter displaces the regular bedding of the limestone next below the thick shale band (on the west aide of the line), arching up the layers of rock that were deposited over it. Here the section is : — Limestone, rubbly at top - - . Dark Shale Limestone - . . - - Sand . - . . . Stone --.--. Dark Shale .... Limestone . - - - - Shale parting .... . — Limestone ... ..90 Shale parting .... . — Limestone -..-.. — About 16 chains north of this, a fourth fault, trending E. 40° S., throws down the beds 3 feet to the north, after which they run nearly horizontally to the end of the cutting. The Lincolnshire Limestone is well exposed along the road from a quarter to half a mile west of Nooton Hall, and is worked in a small quarry to about 6 feet from the surface. The upper 2 feet is rubbly, below which is grey, blue-hearted, oolitic limestone. Immediately to the west of this, the road- cutting carried under the joint Great Eastern and Great Northern railway affords an interesting exposure of faulted limestone and shale. About 33 feet of rock, in beds varying from 6 to 18 inches in thickness, is seen on either side of the railway-bridge. 50 yards east of this, a large fault brings down beds altogether higher in the series, viz., the shale-band previously described, and several feet of the oolite overlying it. The amount of " throw " of this fault must be nearly 40 feet. 20 yards further east, a much smaller fault of 6 to 7 feet throw raises the shale-band to within a foot or so of the surface, reversing pro tanto the western fault. The direction of the latter is W. 28° N., and of the former, W. 30° N., but there are indications of a more complex faulting, thus, |M , where the parallel lines indicate the plan of the main faults in the width of the roadway, and the oblique stroke, an inter- mediate fracture trending due west, and throwing down the shale on the south nearly to the level of the road. The hade of the intermediate or eastern fault at their junction is fully 45°. The shale-band at this point is 4 feet 6 inches in thickness, with two bands, two inches thick, of marly stone, about a foot from the top and bottom respectively. W. H. D. Ft. In - 15 - 3 - 6 - 3 - 6 - 3 - 6 INFERIOR OOLITE. 49 Half a mile north of Dunston Pillar we find exposed, in a small pit, the following beds ; — Ft. In. Rubbly limestone - 4 Hard grey rather creamy limestone - 2 Grey clay, said to be about - - 1 6 Under this is more limestone. Three-quarters of a mile north of Nocton Grange a small quarry shows : — Ft. In. Rubbly limestone - - - 3 to 4 Creamy-looking limestone - - - - 2 Pinkish thin-bedded oolite with clay partings - 2 6 Coarser thick-bedded oolite - - - — At the farm half-a-mile N.N.E. of Nocton Rise is a quarry showing the following beds : — Ft. In. Rubble - - - 3 to 4 Fine oolite - - - - - 4 6 Softer, sandy limestone ... 20 Hard coarse oolite * - - - - 4 6 At the cross-roads about a mile west of Potter Hanworth, a small pit fur- nishes the following details : — Ft. Rubbly limestone - - - - 3 Coarse fissile oolite - - 2 Hard massive pinkish ditto - - - - 2 Hard blue shelly limestone - - - - 1 Grey clay - - - - - - — On the south-east of Branston Church, three quarries furnish, when taken together, the following section : — Ft. In. Rubbly limestone - - - - 3 White marly limestone . - - 10 Marly clay - - - - 6 Cream-coloured oolitic limestone - - 2 Marl - - - - 4 White chalky stone, slightly oolitic 4 Marl - - - - 3 Oolitic liinestone - - - - - 7 Clay .° . . . - 2 Massive oolitic limestone - - - - 4 Clay band - - - - - 2 Oolitic limestone - - - - - 1 At about half-a-mile east of Branston Church is a quarry showing the following series: — Ft. In. Grey oolitic limestone - - - - 3 Coarse, brown, crumbling oolitic sand - to 6 Hard grey oolitic limestone - - - - C Hard grey limestone, not oolitic, very fossiliferous - 2 Brown laminated clay - - - - 4 Creamy limestone - - - 2 W. H. P. And in another quarry near by, is seen : — Ft. In. Soil and rubble worked into remains of shale 6 Stone - - - - - - 2 6 Marly stone • - - - 6 Stone with irregular bands of fossiliferous shale - 3 Shale - - - - - - 6 Hai-d, fine-grained, blue-hearted liinestone - - 2 i .50058. D 50 THE LOWER OOLITES. On the railway, a mile north-eastward of Branston, a cutting somewhat obscured by grass in its upper slopes shows the following beds : — Marly shale, probably several feet thick. Limestone - - - - 6 ft. 6 in. to 8 ft. Blue marly shale - - - - 10 in. to 1 ft. Limestone. A quarter of a mile further north, the rise of the beds in that direction brings 13 feet of the lowest bed here named into view, to be speedily cut off, and thrown down out of sight by a fault of nearly 60 feet throw, trending E. 28° S. W. H. D. At some cottages about half a mile north-west of Branston Mill is a pit in marl with ooliths. At a farm a mile and a quarter west of Branston, a small quarry shows 4 feet of rubbly limestone over 6 feet of good oolite, coarse-grained at top, finer below. Half a mile south-west of this, coarse oolite is quarried to a depth of 10 feet, the upper 3 feet being rubbly. Half-way between Branston and Canwick, a quarry, filled up in 1878, showed the following section : — Ft. In. Coarse rubbly oolitic limestone - - - 4 Clay - 4 Oolitic limestone ■ - - - 6 Clay 10 Oolitic limestones - - - - 3 The cutting of the Great Eastern and Great Northern Joint Railway at Washingbrough affords a very fine section, extending from the Northampton Sand to very near the top of the Lincolnshire Limestone. At the bridge, about a quarter of a mile south-west of Washingbrough Church, we have the following measurements (checked by the accounts of prehminary borings kindly furnished by Mr. Abbott) : — Rubbly limestone, soft and marly - - . Solid limestone . - - - Hard clay and stony marl, fossiliferous Limestone, soft and marly in parts Hard marl and stony shale - - - - Limestone - - - - - Marl .-.-.- Limestone - . - . - Clay ... . . Limestone . . . - Marl ..-.-- Limestone . - . . - Lower Estuarine Clay and Northampton Sand iron- stone as described on p. 39. At the cross-roads, half a mile to the south-east of this point, we get an additional thickness of 11 feet on the top, with a loss of 20 feet at the base, and the following section is presented : — Soil- Loose stone and rubble . . - Limestone, the last 20 inches blue - - . Hard grey marly shale ... Limestone, blue above and below, yellow in middle Shale, black and yellow Limestone ...--- The beds dip but little more than the slope of the surface, and the thick shale band only passes below the level of the rails near the east end of the cutting. If 30 feet be taken as the thickness of limestone above this shale we have 66 feet as the entire thickness of the Lincolnshire Limestone. Ft. In 6 9 1 8 4 10 4 4 11 1 6 3 5 6 3 10 7 18 4 Ft. In. 9 6 6 10 9 5 6 9 9 3 INPERIOE OOLITE. 51 The shale band is again seen in some old pits a quarter of a mile east of the church, where the following beds are exposed : — Purplish sand with carbonaceous markings, 2 feet. Thin, band of ferruginous sandstone. Yellow loam. The limestone comes on just above. Eastward of this is a quarry situated at the outcrop of the limestone from beneath the Upper Estuarine series, which, in a weathered, and possibly frost-moved state, is seen at the top of the section, consisting of the following beds : — Ft. In. Sandy loam, laminated in places - - 8 to 10 Broken limestone - - - - 2 Marly band- - - - - 3 Thin-bedded ooUtic limestone - - - 6 Hard ferruginous sand - - - 3 Tabular oolitic limestone - - - 5 The dip attains an angle of 10° to N., 35° E. In this pit is a large swallow hole 10 feet in diameter, over a fissure, lined by fine grey sand with lumps of ferruginous sandstone, the centre occupied by a gravelly mass of coarse sand, quartz pebbles. Oolite fossils, fibrous carbonate of lime, overlaid by a reddish-brown sand about a foot thick, and this by sandy wash. "We have here first the Upper Estuarine beds, next a mixture of these with the relics of Drift, then, after the subsidence of these into the swallow hole, a wash down of the Estuarine beds over all. A quarry, rather less than half a mile E. S.E. of Canwick Church, shows the following section : — Ft. Rubble - - - - - - 2 Chalky Umestone - - - - 1 Marly clay - - - - - - 1 Whitish oolitic limestone - - - 2 Marly clay with bands of chalky limestone. On the north side of the road, about five furlongs east of Canwick Church, a small quarry shows the following : — Ft. In. Rubbly limestone - - - - - 4 Regularly bedded limestone - - - 2 Brown clay - - - - - -06 Massive grey, blue-hearted ooUte - - 5 At the north-west corner of the wilderness of old quarry-spoil, now planted and converted into a wood, a little to the south-east of Canwick, the lowest beds of the Oolite were seen in 1878 resting on ironstone of the North- ampton Sand series. They consisted of thin-bedded flaggy limestone, of which 8 feet were seen. W. H. P. II. North of Lincoln. Mr. Dalton writes as follows : — In an account of the geology of Lincoln published in 1839* by Mr. W. Bedford, and subsequently, with the addition of map and section in 1843, a section is given ranging from the crest of the hill north of the Cathedral down to the river, compiled from various sources and containing some quaint references to fossils, &c. The author evidently supposed that the entire series of the Lower Oolite was represented, and misunderstanding the term Cornbrash, he took a bed of the Oolite (containing fossil shells, * Bedfoed, W. Mag. Nat. Hist., ser. 2, vol. iii., pp. 553-556 (1839), and Papers Lincohih. Topogr. Soc. for 1841-2, pp. 15-28, plates i., ii. (1843). T> 2 52 THE LOWER OOLITES. which seen in section, resemble, with a little stretch of imagina- tion, the awns of barley) to be the Cornbrash of geologists, although from the close texture of the stone, he preferred the term Forest Marble. In the following transcript of his remarks, interpolations are given in square brackets [ ]. 1. Alluvial Soil, from 6 to 10 inches in thickness. 2. Rubbly Stone; Cardiaov Stone Cockles [and the Mactra] are profusely- distributed here. 3. Called the Blue bed ; a hard limestone wherein Spar and chrystalline Cockles [Lucina bellond] are found. 4. Knobbly or Boss Rubble ; contains casts of shells. A layer of Marie lies underneath. 5. The Shell bed ; Stone Cockles in great variety are found in this bed. A layer of Marie lies underneath. 6. The Blue Limestone bed; contains the Mactra, a species of the Muscle. 7. Three beds of the Grey Limestone, each bed intercepted with Marie ; Oysters, Murex, the Lobster-tailed Nautilus or Miller's Thumb, the Chiton, and large Ammonites are found in these beds. 8. Three beds of fractured limestone, each bed intercepted with a layer of Marie. 9. A strong limestone bed called the Roof bed . . . mined . . .for building the Cathedral ... to a great extent. 10. Three thin knobbly beds, intercepted with Marie. 11. The Oolite Freestone bed; Calc Spar occurs here in Rhombic and Prismatic crystals. Large Ammonites ^nd the Teredo or Lapis Syringoides, and Fossil Wood are found in this bed. 12. The Silver bed; it abounds with Cornbrash and Archimedes Shells [Nerintea'] ; it is allied to the Forest Marble ; . . . . prismatic and rhomboid Calc Spar is found in this bed. 13. A bed of good building Stone, superior to the Silver bed, about 16 inches in thickness ; this bed abounds with Cornbrash and Archimedes Shells Between the fissures, the Agaric mineral occurs in delicate opaque crystals. The Dagger Shells, Razor-sheath, and various other shells are found in this bed. 14. Two beds of good stone, with Oolite disseminated. In the first bed fossilized branches of trees sometimes occur, lying horizontally. Prismatic Calc Spar in bold crystals occurs in this bed. In the second bed the Ostrea diluviana is found. 15. The Oolite or Roestone bed is nearly 2 feet in thickness. . . . It is a hard Oolite, and becomes harder by exposure In some parts of this stratum it is Blue-hearted. ... It will not Inirn into quickhme. 16. A bed of indurated Clay, 6 inches in thickness. 17. A bed of very hard Blue Stone. A bed of very hard indurated Clay, 4 inches thick. 18. A thin bed of hard fine sandstone, firmly united to 19. The Grey Oolite bed, which is as firmly united to 20. The White Oolite bed. These three beds form one massif's bed, nearly 4 feet in thickness. A thin layer of clay, about an inch in thickness. 21. I/OM)«- OoZi^e bed .... lies upon a bed of Yellow Ochry Earth, underneath which the springs begin to appear. 22. Ochry Ferruginous-stone bed [Northampton Sand]. 23. Ferruginous gravel [Phosphate nodule bed] and Sand bed, underneath which. Pyrites in masses occur in some parts, just as we enter the 24. Thick bed of Olunch Clay [Upper Lias]. Ammonites, Nautili, and Belemnites occur in this bed. This clay shale is from 60 to 90 feet in thickness, and must be bored through into the heart of a rocky • crust lying below, before water can he obtained. INFERIOK OOLITE, 53 25. Ferruginous gravel and Sand bed [Marlstone Rock-bed] ; intervenes between the two beds of Clay, with nodules of Iron Pyrites. 26. Thick bed of Blue Clay shale [Middle Lias clay], an excellent clay, when ground, for tiles and floor-bricks. In this bed are three seams of rubbly Ironstone-clay, which dip towards the east, from 3 to 4 inches in thickness; the second seam is 2 feet below the first seam, and the third seam between 3 and 4 feet below the second. Fossilized Oysters, Muscles, and Periwinkles are found in this bed. See Mr. Foster's clay pits near the west common [now closed]. For like reasons to those given before, we shall divide the area of the Inferior Oolite by the Roman Road running north from Lincoln. a. On, and westward of, the Roman Road. On the east of the road, a mile and a quarter north of the Cathedral, a quarry measured by Mr. W. D. Carr gives the following : — SoU Yellow shelly oolite in three courses. Pinna, Modiola, and Nerincea abundant - - . - Yellow marly clay - - - . Hard yellow marly limestone with brown eoliths Yellow marly clay - - - . - Semi-concretionary limestone - - - Brown shale - . - - - Impure earthy limestone, blue above, yellow below Blue shale -...-- Blue impure earthy limestone . - - Blue shale ------ Marly limestone . - . Yellow shale ... Marly limestone - . - . Black and yellow shale - - Yellow limestone with brown ooliths Clay .---.. Fine-grained limestone, with many small Gastero- poda ; not oolitic - - - . Clay - Semi-concretionary marly limestone Black and yellow shale Coarse yellow limestone - . - . Coarse yellow shale - - - - Good shelly limestone . . - - Coarse yellow shale . - - - Yellow oolitic limestone, with Montlivaltia and shells Coarse yellow oolitic shale Fine-grained limestone, slightly oolitic, with a clay parting in the middle. Corals, wholly oalcitized, occur above the parting, and Pholadomya in position of life below it - - - - 3 1 23 W. H. D. A little to the north of the last, west of the road, a quarry shows : — Ft. In. Limestones with six-inch clay bands - -30 Limestone vpith clay partings - 3 to 4 Silty fossiliferous clay ^ith nodules of blue hme- stone - - - - - 9 Creamy limestone - • - 4 Oolitic limestone, W. H. Penning. Ft. In 2 5 6 2 9 1 5 3 4 2 5 2 1 ,5 1 8 2 11 1 4 1 4 10 4 4 8 6 1 5 9 - 3 - 2 - 6 - 9 - 3 5 to 6 54 THE LOWEE OOLITES. In the brickyard belonging to Messrs. Swan Bros, and Bourne on. the North ClifF, the lowest beds of the Oolite are exposed on the brow of the clay pit, and those immediately above them in a small quarry a few yards in the rear. W. H. D. East of Burton Church is a quarry in fine-grained cream-coloured oolite. On the Roman Road, due east of Burton, a quarry by the southern lodge shows : — Ft. In. Rubbly wash - - - Limestone - . - - Brownish clay - - - Creamy limestom; - . . Clay Fine-grained, limestone - . - Oolitic limestone. A little northwards of Riseholme are pits on both sides of the road, showing grey shaly clay, with fossils and a band of limestone nodules, separating the rubbly rock above from the bedded oolite below. , Half a mile east of South Carlton : — Ft. In. Brown loam - - - - - 3 Thin-bedded creamy oolite with clay partings - 3 6 Thick-bedded oolitic ironstone - - - 2 By Watering Dyke House : — North of same : — West of road near by : — Ft. Ft. Ft. Bubbly oolite - IJ U 1 Thin-bedded coarse oolite - - 2 3 3 North Carlton, 6 furlongs S,E. :— i mile E. :— I mile E. :— Ft. Ft. Ft. Soil and rubbly oolite - 6 4 4 Thin-bedded oolite, with clay partings . - 6 5 3 W. H. Penning. The quarries near Scampton, Aisthorpe, Brattleby, Cammeringham, and Ingham Mill present similar sections to the above. b. East of the Roman Road. The railway cutting west of GreetweU traverses almost the entire thickness of the limestone, the uppermost beds of which, after passing under the Great Oolite series, are brought up again by a fault for a short distance, forming a narrow belt between the overlying beds on either side. The width of this belt measured along the railway is 175 yards, but the true width, at right angles to the boundary lines, is about 50 yards. The upper beds of the lime- stone are rubbly for 5 or 6 feet dovmn, and then pass into massive thick-bedded oolite. No shale band is present in the exposed thickness of 30 feet. W. H. D. The western part of the cutting is much obscured by weathering, and only the stouter bands of rook project from the marly detritus. There appears to be a small fault, about 200 yards from the western end of the cutting, where the general sequence is as follows : — Ft. Rubbly limestone and marl - - - 4-5 Oolitic limestone - - - - - 1 Rubbly oolite' ■ - - - - 3 Oolitic limestone ■ - - - - I Grey clay, passing down into - - - 1 Yellowish sand with ironstone concretions - - 1 Rubbly limestone . - . . 6-7 Hard oolite - - - - - -1 Rubbly limestone. Ft. In. 6 2 6 6 3 4 6 H. Penning INFEKIOK OOLITE. 55 On the hill to the north of the cutting the Oolite has been proved by boring to a depth of 65 feet ; hut tljis may include overlying beds, and an allowance of 4 per cent, must be made for the dip, 14°. In Mr. Kirk's' quarry, east of the gaol, the ironstone of the Northampton Sand series has been reached in a well a little below the floor of the quarry. The visible section is as follows : — Rubbly limestone . . - - • Marl, with limestone nodules Limestone in beds varying from 6 inches to 1 foot Marl ------. Hard grey sandy limestone Blue-hearted sandy limestone Ferruginous sandy limestone. W. A similar series is exposed in the gaol quarry, and the same beds, with local difierenees, are worked on the Wragby Road, half a mile to the north, in a quarry showing the following particulars : — Ft. In. Soil .---.. Rubbly stone ... Marl, with limestone concretions Rubbly stone ... Good limestone - - ■ Shale -.---- Stone Stone .... Shale Stone . . . . - Stone - . - - Ferruginous sandy stone. To the eastward of the fault, in the neighbourhood of Bunker's Hill, are four small pits in the Oolite, two on either side of the road. Those on the north of the road are in different horizons, in consequence of the dip, the top- most beds in the western passing below the floor of the eastern quarry. The same is the case with the openings south of the road, the nearer of the two being in higher beds than the further. The dip here is a little higher than usual, being fully 5° towards the E.N.E., and a small fiiult with a W.N.W. trend, and a northerly downthrow of 3 or 4 feet traverses the hole dug for a limekiln in the northernmost of the two southern pits. On the Nettleham Eoad, rather more than half a mile from the Cathedral, a small quarry now abandoned shows, under 5 feet, of rubble, a band of fos- siliferous shaly marl nearly 3 feet thick overlying 6 feet of limestone. Immediately to the east of this is a fine series of quarries above 100 yards in length, and ranging in depths varying from 20 to 30 feet. The beds exposed in these are below the thick marl band last referred to, relics of which used to be seen at the west end of the larger excavation, blending with the soil and rubble on the top of the workable stone. The extension and deepening of this part of the quarry in 1884 has destroyed these traces, giving instead a much more complete section of the lower beds behind the roadside cottages, the following measurements of which are kindly furnished by Mr. W. D. Carr : — Ft. In. 1. Vegetable soil - - - 2. Rubbly ooUte - 3. Semi-crystalline shelly limestone 4. Irregular shale band 5. Fine shelly limestone ' - 6. YeUow marl, with irregular band of limestone 7. Fine-grained limestone, irregularly oolitic 8. Yellow marly ooUtic shale 9. Good shelly limestone 10. Coarse earthy shale - 1 - 4 - 1 2 - 2 - 7 - 4 - 2 7 - 1 6 - 2 - 1 4 - 1 1 5 2 9 2 5 1 6 5 9 5 1 6 5 -5 19 6 Shell-rock - - 14 6 J i 50058. E GO THE LOWRR OOLITRS. As the Great Oolite Limestones pass out iu Sheet 86, apparently intercligltating with clays, aucl finally permitting of the direct superposition of the Great Oolite Clay upon the Upper Estuarine Series, the association of clay bands, as in the well, with the limestones of the Great Oolite is only to be expected. Mr. Dalton furnishes the following observations : — Between Soopwiok and Blaiikney the Great Oolite Limestone is traceable by its fragments, thickly strewn over the fields, and in the ditches surrounding them it is occasionally visible in situ. It is obscurely seen on the railway north-west of Metheringham, and consists of hard blue shelly ragstone with clay bands, also crowded with fossils, Ostreae predominating. The east side of Dunston village is situated on this rock, which is occasionally e.\:posed in foundations, &c. A small outlier has been detected east of Dunston Station. The limestone appears in the bed of the brook at Nocton, and forms a bold feature half a mile further northwards. It is again laid bare in the stream west of Potter Hanworth Church, and a small outlier was revealed in 1882 by the lowering of the road at the Station. It is next seen in the ditch at the boundary of the City of Lincoln, and on the north side of the wood it forms a hard bottom for a considerable length of the ditch, extending to the road. It is exposed in ditch-seetions on both sides of the little valley half a mile to the north-west of this, and its lower beds are seen in the Heighington railway cutting to a depth of 8 feet ; they abound with the usual Brachiopoda and oysters, and lie in a slight synclinal with a general eastward dip. The rock is again seen in the brook east of the village, and in a small exposure a quarter of a mile to the south ; thence it rises to cap the hill to the north, but is obscured on the east by gravel. It is next seen in the road on each side of the little hollow east of Greetwell, and exhibits a sharp dip to the east. "Where the railway cutting crosses the promontory of this rock, the section is much obscured; but the faulted- down outcrop, 16 chains westward of the bridge, is the most complete exposure in the district, the full thickness of the rock being laid bare on a face the slope or " batter " of which permits of examination in the completest detail. There appears to be a gradual passage from the clay below, through marl, to the hard ragstone constituting the bulk of the rock, which abounds in fossils of various classes. Among these are palatal teeth of Fish, MoUusca, Echino- derms, and Corals. The rook is 15 feet thick, and dips to the north-east at 14° at the base, rapidly flattening eastward, and becoming nearly horizontal at the fault which brings it against the Inferior Oolite. The fault strikes W.N.W., and slickensideg and spar are observable on the faces of rock brought into contact by it. Eastward of Bunkers Hill, the limestone is well seen in the Reepham brook, and the fields at its source (Cunsike Spring) are thickly strewn with fragments. Two small ponds at Nettleham Lodge, three-quarters of a mile south-east of the village, are dug in the rock, which was also revealed by draining north of Nettleham. From near Friezeland to Welton the rock is intersected by deep ditches, artificial drainage being necessitated by its waterlogged condition. Such exposures are also abundant near Honeyholes and north of Haokthorn, both on the bridle-road to West Firsby, and in the fields right and left of it. In the streams constituting the head waters of the Ancholme, small exposures are seen westward of Spridlington and Saxby, and the rock is raised for road-metal in a series of old quarries, from a mile to a mile and a quarter, westward of the latter village. W. H. D. At the cross lanes, or path-roads, north of West Firsby, Great Oolite Lime- stones are exposed, dipping in an easterly direction at 2°; the exposure continues for some chains by the turning to Saxby, the limestones being visible to a depth of 5 feet, in horizontal beds. In a snaall quarry on the north-west side of the cross lanes, 7 feet of Great Oolite Limestone is exposed : the beds undulate, dipping north at 5°, and N,40°E.at2°. GREAT OOLITE SERIES. 67 At a quavter of a mile north of the cross lanes. Great Oolite Limestone is exposed to a depth of D feet in a ditch. Further north, it is exposed to a depth of from 2 to 3 feet by the road to the Lodge, at the ninth milestone on Ermine Street. The limestone is also shown in a drain on the south of this road at half a mile east from the turning to West Firs'oy. At about a mile west from Owmby Church, Great Oolite Limestone is exposed to a depth of from 6 to 9 feet in a quarry. In one part of the quarry the lateral divisions, which, as a rule, give the rock a shaly appearance, are not developed, so that the section seems to consist of three or four distinct beds, in descending order, as follows : — Ft. In. Grey, partly crystalline, limestone (often of a pepper and salt grey hue), with numerous fossils - - » - 2 Limestones similar to above - - - " i 2 Hard, comparatively unfossiliferous, blue limestone - 1 C In other parts of the quarry the rock splits into shaly pieces, of from 1 to 3 inches in thickness, but lines of more shaly material give to it on the whole a distinctly bedded aspect; the beds are horizontal. In the western parts of the quarry, from 5 to 6 feet from the surface, the beds are fossiliferous and partly crystalline, the limestone often presents a somewhat granular texture, and the mixed grey (pepper and salt) colour. From these beds, for 4 or 5 feet downwards, hard bluish-grey, less fossiliferous limestones extend, resting upon an irregular bed of blue limestone, which forms the floor of the quarry. Impersistent beds of brown sandy ferruginous rock occur in the limestones at between 3 and 6 feet from the surface. At about 30 chains south of Normanby Cliff Farms a foot of Great Oolite Limestone is exposed. Near the letter C in the words Normanby Cliff, and the N in the words Normanby Mill on the Map, rock is exposed, to a depth of 5 feet in the former place. At a mile west of Normanby Church, on the north side of the road, a quarry shows from 6 to 8 feet of grey Great Oolite Limestone. By the bridle-road to Caenby the rock is exposed in ditches on either side of Low Walk Wood houses, also by the eastern boundary of the wood, and in a continuous section in a drain east-south-east of the wood and nearly parallel with the road-track. In the drain, Boulder Clay conceals the rock in places. Great Oolite Limestone is further evidenced by surface stones north of Low Walk Wood, and it is exposed in a drain running in a southerly direction from the road to Caenby, at about a quarter of a mile west of Low Walk Wood houses. East of Spital and south of Norton Place Park, Great Oolite Limestone is exposed by the path roads, and in drains and ditches between them. In one drain about a mile and a quarter due east from the little church at Spital, the upper bed resembles Oornbrash in external appearance. The outliers of Great Oolite at the 12th milestone on Ermine Street are evidenced by feature and surface stones on the west, by feature (slight) and partial exposure in a ditch on the east. At about half a mile east from Norton Place House, in a ditch by the north side of the plantation, the junction of the Great Oolite Limestone and Upper Estuarine beds is shown. The section is shown in the accompanying . figure : — Fig. 3. E. Ditch section half a mile east of Norton Place House. W. e Horizontal scale, 1 inch = 40 yards. E 2 68 THE LOWER OOLITES. Reddish brown and drab surface sand (s.) caps the section. Proceeding from west to east we encounter (e.) rubbly fossiliferous rook with Avicula,^ Rhynchonella, and Univalves, from 6 inches to 2 feet thick, upon {d.) a mass ot broken OslrecB in a clayey matrix. At a; red brown sand with small stones, more or less worn, may be a relic of fiuviatile deposit, or of Grlacial Drift ; abutting against it is stiff grey clay (e.), overlain by (/.) Great Oolite Limestone, 2 feet thick, in stone beds which seem to pass out eastward into rubbly baiids of broken Ostrece ; at 4 chains further east, the hard rook seems to predominate, but it is associated with the broken shelly matter. We have here the type so frequently exhibited by the Great Oolite from Snitterby northward into Sheet 86, namely, the irregular association of tolerably hard irregular shaly limestones with softer beds of decomposed fossiliferous limestone, or of broken shells in a loamy or olayey matrix. As (c.) is evidently the hard bottom bed of (/.) its position must be due either to a small fault at x, or to pressure. The surface fragments in this ditch section very strongly resemble Cornbrash. On the east of JNorton Place fossiliferous limestone fragments, greatly resembling Cornbrash, occur on the surface, and have also been brought up with the roots of fallen trees in the plantations near the house. Similar fragments are usually found in the higher parts, on the surface and in drains ; at a slightly less elevation Great Oolite Limestone fragments are abundant, the surface soil being reddish brown and sandy, with bits of flint, and occasionally foreign fragments. From the above indications an outlier of Cornbrash was first carefully mapped, but the absence of Great Oolite Clay to separate it from the Great Oolite Limestone proved an insuperable obstacle to that idea, which was abandoned, as also ideas of glacial transport, the simple explanation being, the existence in the Great Oolite of beds lithologioally and palaeontologically very similar to the Cornbrash; a like difficulty was experienced in Sheet 86, near Waddingham, which was only cleared up by the evidence obtained in mapping the Bishops Norton area. On the north of Norton Place, south of the Lodge, the boundary of the Upper Estuarine beds and Great Oolite Limestone is by no means clear, a bed or two of siliceous limestone was noticed in a drain, apparently in the Upper Estuarine Series. Great Oolite Limestone is at the surface in the village of Bishops Norton ; it is also exposed in a quarry at about a quarter of a mile from the village on the east. By the turning from the Atterby and Snitterby road, towards Sminhays, Great Oolite Limestones are exposed in a ditch for some distance. Near Snitterby, on the south. Great Oolite Limestones are exposed in small pits, also by the road on the east side of the village, and in drains east of the Rectory. Great Oolite Clay. The Great Oolite Clay occupies the outcrop slope of the Cornbrash escarpment feature, but its breadth expands in places where it lias been spared by denudation on the lower part of the dip-slope of the subjacent limestones, as appears to be the case west of Saxby, and where the Cornbrash has been denuded from the crest of itij feature, as exemplified on the west of Reepham. The Great Oolite Clay is affected by faults between Dunston and Nncton, and near Lady Wood (between Heighington and Potter Hanworth), ou the south of the Witham valley ; it is con- cealed by Drift near Metheriiigham, Nocton, Potter Hanworth, in sever;! 1 places between Reepham and Welton, and near Normanby Mill. The clay is about 25 feet* in thickness ; it is of a dark bluish- grey colour often mottled with green, and contains numerous * Vide Appendix, Sudbronisc llohne well. GREAT OOLITE SERIES. 69 shells, principally Ostrece, which, as far as the limited depth oF its exposures permit of judging, are most abundant at its junction with the Cornbrash. In the "Well at Sudbrook Holme the Great Oolite Clay is described as : — Ft. In. Ft. In, Green clay - 11 6\„, „ Dark clay - - 14 OJ"^^ " Mr. Dalton remarks : — This series is rarely more than 20 feet in thickness, consisting of blue clays, weathering yellow to a considerable depth, atmospheric action being aided by the abun- dance of shells rendering the clay fairly permeable. From the rarity of exposures, other than mere ditch-sections, the fossils have not been much studied, but appear to be numerous in individuals rather than in species, Ostrece and Rhy iichonelleB preponderating. An old brickyard near Metheringham Station was worked in these clays, which were also raised in draining between here and Dunston. They were seen near Nooton Hall in ditches and in the brook, and in the fields north-west of Potter Hanworth. Near Lady Wood and to the north they are largely concealed by gravel, which, towards Heighington, covers more than half of their narroiv outcrop. The hill north-east of Heighington is likewise poor in exposures, the wash of gravel down the slopes affording natural drainage on what, nevertheless, we must map as clay land, disregarding material not in place. West of Cherry Willingham is an obscured railway cutting in these clays ; they were also deeply drained in 1883, midway between Cherry Willingham and Nettleham. They were also seen north and south of Sudbrook, in the flanks of the feeders of the Langworth that pass by that village. Eastward of Welton several small e.\posures were seen, and the clays are revealed in ditch sections near Hackthorn Mill and Spridlington. Westward of Saxby, by a freak of denudation, the outcrop is widened to nearly three-quarters of a mile. The patch of Boulder Clay has probably assisted in protecting the clay whilst the Cornbrash has, owing to the approach of two streams, receded, leaving an outlier only, in the average position of its escarpment. W. H. D. From Saxby northward its position between two hard beds would render the Great Oolite Clay an easy division to trace, in spite of the general absence of good exposures, were it not that three patches of Boulder Clay, west of Saxby and Owmby, render its junction with the underlying limestone uncertain, more especially in the vicinity of Normanby Mill. Near the road to the Ermine Street, at about halE-a-mile from Saxby Chiurch, dark grey and green Great Oolite Clay was shown in a ditch. In a ditch running nearly east and west across the Cornbrash feature, between Normanby and Oaenby, the evidence proceeding east from the stream between Normanby Mill and Glentham Mill is as follows :~ For 6 chains from the stream, soil, apparently alluvial, on Great Oolite Limestone. For 6 chains up the slope, bluish and greenish Great Oolite Clay, probably under a Boulder Clay soil. For 30 yards, a brown soil with small fragments of Cornbrash upon greenish and dark grey clay, apparently mashed or squeezed up with broken pieces of Cornbrash ; the ditch here is from 3 to -1 feet deep. For 6 chains, Cornbrash, on Great Oolite Clay full of OstreiE. For 94 yards, Cornbrash resting irregulai-ly upon Great Oolite Clay. At this point, about 24 chains east from the stream, the Great OoUte Clay is near the surface. At about a hundred yards further on, greenish clay is 70 THE LOWER OOLITES. visible. At 6 chains further east, Great OoHte Clay is shown at the hottom of the ditch, and at about 4 chains further, and 9 chains from the road to Caenby, it is exposed vmder from 1 to 2 feet of Cornbrash. By the high road near Glentham Mill, dark grey Great Oolite Clay is exposed. Great Oolite Clay was turned out from drains on the slope below the Cornbrash both north and south of the road from Bishops Norton to Glentham. Great Oolite Clay is exposed near its junction with the Cornbrash east of Bishops Norton. From Sminhays northward the Great Oolite Clay is entirely concealed by sand and gravel, the next evidence of it at the surface being near Old Mill and Waddingham in Sheet 86. Cornbrash. The Cornbrash in Sheet 83 is very thin, being from 3 to 5 feet ; but its characteristic appearance, as described by Professor Judd,* makes it at once the most distinctive and persistent member of the Great Oolite Series, although there are fosslliferous beds locally present in the Great Oolite Limestone which are hardly distinguishable from it. From the crest of its escarpment the Cornbrash falls gently eastward to the foot of the Kellaways Eock feature ; the breadth of its outcrop is considerably less than that of the Great Oolite Limestone. The continuity of the Cornbrash is broken by faults in two places south of the Witham valley, near Dunston and Lady Wood ; but near the latter place and around Potter Hanworth it is concealed by Glacial deposits, and by gravels near Metheringham and Blankney. West and south of Eeepham, north of the Witham valley, the Cornbrash is concealed by Boulder Clay, by which it is also partially covered in several places as far north as Welton. The Sudbrook Holme boring describes the Cornbrash as stone, 4 feet 6 inches in thickness, separated by 7 feet of blue clay from the Kellaways Sand above, and resting upon Great Oolite Clay 25^ feet thick The following notes on the southern part of the Sheet are by Messrs. Penning and Dalton : — Mr. Penning remarks : — The most southernly exposure of the Cornbrash in Sheet 83 is a small pit, 2 or 3 feet deep only, about three-quarters of a mile eastward of Scopwick. The rock here is, as usual, a thin-bedded shelly lime- stone of ferruginous aspect, but the flakes when broken show a deep-blue interior. The very limited extent of the weathering may be due to the com- paratively recent removal of the protecting Oxford Clay, but the compact crystalline character of the rock probably accounts for the arrest of the oxidation. W. H. P. A trace of the rock, much disintegrated, was observed in the making of the road from Metheringham Station to Blankney Hall. A fairly persistent feature extends thence to Dunston, where the rock is seen in the brook and in a little quarry north of the fault. Thence it forms a well-marked escarp- ment and dip. slope to Potter Hanworth, whence it is lost under Boulder Clay and gravel for about a mile. ology of Hutlaud, Geol. Survey Memoir, |ip. 218, 21!). GREAT OOLITE SERIES. 71 The outlier south of Lady Wooci is indicated by feature, and the rook was exposed in a fresh-cut ditch in 1883 ; its presence on the hill south-east of Heighington was determined by similar evidence. W. H. D. In the fields south of Cherry Willingham the rubbly top of the Cornbrash is raised for road-metal, and an abandoned pit half a mile west of the village showed, in 1878, similar rubbly siliceous bluish ragstone. Half a mile to the north of the village there were, at that time, two small pits now filled up, in which were noted the following particulars : — Grey Boulder Clay, in patches, attaining a thickness of 3 feet. Loamy sand (probably Kellaways Sand) in places as much as 4 feet thick. Blue silty clay of varying thickness, probably averaging 1 foot. Hard blue shelly limestone, weathering brown, with much fossil wood and plant-markings. W. H. P. The rock is seen in the brook below and' in the meadows to the east, and was laid bare in draining on the hill between the brook and the Roman Road to the north, on which appear to be two small outliers di Cornbrash. The large, though shallow, pits in the south-west part of Sudbrook Holme Park have yielded to the assiduous researches of Mr. Carr, of Lincoln, no fewer than 80 species of fossils. The rock is seen at intervals, north of Sudbrook, round the hill into Scothern; it is quarried three-quarters of a mile north-north-west of that village, and at Dunholme, where the clay at the base of the Kellaways Bedii is seen overlying it. There are two small quarries by the road from Welton to Cold Ha.nworth, and many small exposures in roadside ditches and in the fields on either side of the way to Spridlingfcon. A well-marked feature is persistent throughout, but at Saxby its place is represented by an outlier only, the streams having cut down to the subja'Cent clays on either side backwards to their junction. W. H. D. In the valley near Saxby, on the west, the Cornbrash is for the most part concealed by river valley-gravel, but a small outlying patch of it (mentioned above) caps a low mound bounding the gravel tract on the west, and showing Great Oolite Clay ploughed up on its slopes. From Saxby northward, the Cornbrash is well evidenced by feature, and frequently also by surface soil, the rock being so homogeneous in character that a description of its appearance in one exposure would, except as regards thickness, apply to all. There is no evidence that the Cornbrash attains a greater thickness than 4 feet. Near Normanby Mill the Cornbrash has been ploughed up on its feature. By the road from Normanby to Caenby, Cornbrash with its characteristic fossils has been turned out of the ditch. A drain running across i the Cornbrash feature nearly west from the road, (the evidence in detail is given in the. notes on Great Oolite Clay) shows from 1 to 2 feet of Cornbrash at 9 chains from the road, and for nearly 20 chains further west the Cornbrash is visible at intervals upon the Great Oolite Clay, its irregular junction with it being due, either to minute undulations or to surface pressure, as there is a strong probability that glacial agency in some form operated upon the dip-slope of the Cornbrash. Cornbrash is also exposed in a drain running south-south-west from this ditch, at about 18 chains from the road. West of Caenby, the evidence on the Cornbrash dip-slope is very obscure ; the sides of a pond by the road show no signs of the rock ; so we are forced to conclude, either that the Cornbrash is concealed by a Boulder Clay soil, or that it has been partially denuded from its dip-slope, and that an inlying patch of the underlying Great Oolite Clay forms the surface. A similar difficulty is experienced on the north of. Glentham, where the Cornbrash appears to be concealed by Boulder Clay soil extending southward from what appears to be a genuine patch of Boulder Clay. Cornbrash is exposed by a farmyard in the northern part of Glentham, on the west side of the road to Bishops Norton. 72 THE LOWER OOLITES. Cornbrash has been turned out of drains traversing its feature on the south-east of Bishops Norton; it is also exposed in drains on the north and south of the road from Bishops Norton to the Ancholme. At about a mile east of Bishops Norton the dip-slope of the Cornbrash is strewn with its characteristic fragments and fossils, Holectypus depressus being abundant; but as we approach the stream, foreign fragments on the suiface suggest the concealment of the rook by a thin strip of Boulder Clay : if this is the case, it is quite possible that the Cornbrash may have been denuded down to the underlying clay as far south as the road to Bishops Norton. About Sminhays the outcrop of the Cornbrash is very narrow, and hardly makes a feature ; but toward the road to Snitterby it widens. On the north of the road to Snitterby the Cornbrash is scaicely indicated, being covered by superficial sand as it passes northward into Sheet 86. The following are a few of the fossils obtained from the Cornbrash of the Normanby district : — Acrosalenia. Andbacia orbuUtes, D'Orb. Holectypus depressus, Leske. 4 Khynchonella concinna. Sow. Waldheimia obovata. Sow. Terebratnla intermedia, Sow. Trigonia, like Tundulata. Opis. Quenstedtia lomigata, Phill. No systematic search for fossils was undertaken ; but as the rock is invariably fossiliferous, the Echini and Terebratulw, weathered out of it, being scattered over the ploughed -portions of the dip-slope of the Cornbrash, tht above list could be very easily extended. W. A. E. U. MIDDLE AND UPPER OOLITES. 73 CHAPTER IX.* MIDDLE AND UPPER OOLITES. Ill Lincolnshire these i;roups are represented only by the KellawayB Beds, and the Oxford and Kimeridge Clays. The Corallian group is entirely absent, and the Oxford Clay passes up into the Lower Kimeridge without the development of any bed which can be taken as forming a line of division. The Portland series is also absent, so that, hitervening between the sandy Kellaways beds and the Lower Neocomian Sands, we have a great continuous series of clays and shales some 800 or 900 feet thick. The breadth of ground occupied by this great clay series is from 13 to 14 miles in the south part of Sheet 83, but narrows northward till along the north edge of the sheet it only measures seven miles. This seems to be caused partly by the thinning of the series northward, and partly by the overstep of the Cretaceous series. The Kellaways Beds consist of sands and sandstones, separated from the subjacent Cornbrash by a few feet of black shaless, and passing upwards into the Oxford Clay. Their outcrop was mapped by Messrs. Ussher and Dalton, A. J. J.-B. Mr. Ussher contributes the following notes : Basement Clays. The Kellaways Rock does not appear to rest directly upon Cornbrash rock, as, if so, the escarpment slope of the former would give to it a greater thickness and consequent importance than we are inclined to assign to it. In Yorkshire, these beds are separated by about 15 feet of shales, " the Avicula Shales " of Mr. Hudleston, " the Cornbrash Clay " of the Survey. In the Midland Counties, clays are associated with the sands of the Kella- ways Rock, and do, in some cases, separate it from the Cornbrash (Geology of Rutland, p. 236, quoted from Prof. Morris' description of the Casewick Railway cutting). " Resting upon this bed (the Cornbrash) is the equivalent of the Oxford Clay, consisting of 10 feet of dark laminated unctuous clay, with gray-brown sandy ferruginous clay. The dark clay contained Ammonites Herveyi abundantly, as well as Modiola bipartita, Trigonia clavellata, Thracia depressa, Nucula nuda, Phil, and Saurian bones," .... {vide also Ibid, p. 237). Prof. Judd includes these clays in the Kellavvays series or lower part of the Oxfordian. The Cornbrash Clay is tluis described (Geological Survey Memoirs, Descriptions of Sheets 95 S.W., and 95 S.E., 1880, pp. 10, 11), " Above this are about 6 feet of finely laminated bluish-grey shale, containing Avicula echinata, Gli/phesa^ Stricklandi .... the so-called ' Clays of the * Written, except where otlierwise noted, by Mr. A. J. Jukes-Browne. t In the Survey Memoir this is erroneously printed Gryphaa. 74 MIDDLE AND UPPEK OOLITES. Cornbrash/ which pass gradually tip into the yellow argilla- ceous base of the Kellaways Rock." It does not appear that the Oornbrash Clays are less connected stratigraphically with the Kellaways Rock than the clays which have been included in the Oxfordian in the Midland Counties, and we may at any rate regard the beds as homotaxial, if not strictly contemporaneous. We should naturally expect to find some representative of this argillaceous base to the Kellaways in Lincolnshire, but exposures of clay upon this horizon are remarkably few and far between, in consequence, no doubt, of the friable character of the overlying sand carried down the escarpment face of the Kellaways by rain, &c. Independently of the evidence furnished by the Brigg boring in Sheet 86, and that at Sudbrook Holme in Sheet 83, the height of the Kellaways escarpment being greater than the esti- mated thickness of the sands would allow, and clay being exceptionally visible at or near its base, we should feel justified in regarding the occurrence of a clay stratum on this horizon as certain, although its persistence may be rather doubtful. To the south of Saxby the indications of clay occurring at the base of the Kellaways have been mapped as Oxfordian, and not separated on the principle adopted in the sheets to the south. To the north of Saxby, lines have been drawn on the map for the clays, in accordance with the mapping of this horizon in Sheet 86, which was completed before the mapping of the Lower Oolites in the north part of Sheet 83 was begun. In the Brigg boring (vide Memoir on Sheet 86), 18 feet of shale was encountered between 2 feet of sandstone (the Kellaways) above, and 3 feet of limestone rock (the Cornbrash) below. In the vicinity of Brigg, the Kellaways is very thin, and to put any other construction on the succession than that given above would render the details incomprehensible. In the Sudbrook Holme boring, which is about 19 miles to the south of that at Brigg, the succession is as follows : — Soil Stone - - - Grey sand Blue clay - Stone (Cornbrash) Here we have 18 feet of Kellaways, as against 2 feet of that rock at Brigg, whilst the Clay below is 7 feet, as against 18 feet at Brigg. Half a mile north of Cherry Willingham "blue silty clay of varying thickness " is noted by Mr. Penning as occurring in pits now filled up, upon the Cornbrash ; his estimate of its thickness is rendered unsatisfactory by the doubtful age of the overlying sandy bed. Mr. Dalton mentions the exposure of the basement clay at Scothern brook, at Dunholme, and near Rutton (see next page). On the slope, just above the Cornbrash outcrop on the west of Saxby, dark grey day was observed above the road, but no continuous exposure. Near Caenby Old Hall the ground is very marshy, and there is a pond at the Hall, both indicative of a clay substratum masked by a wash of sand. 7t. In. 2 5 3 7 4 6 KELLAWAYS BEDS, 75 In the north part of Glentham, clay is evidenced by several ponds just above the outcrop of the Cornbrash. In the road east from Bishops Norton to the Ancholme, just above the Cornbrash feature, grey loamy clay was reached, by spudding through whitish sand. ' At a quarter of a mile within Sheet 86, clay was indicated at 2 or 3 feet above the Cornbrash. In all the above cases the evidence, without regard to the borings, points to the existence of a clayey stratum at the base of the Kellaways Rook, but the absence of exposures and of any indication of its pateontological affinities, gives no clue as to whether it should be included in the Middle Oolites above or bracketed with the Cwnbrash below. W. A. E. U. Kellaways Rock. The following notes are by Messrs. Dalton and Ussher : — The sands are seen to form a slight escarpment from Kirkby Green, a mile eastward of Scopwiok, to Blankney Grove. North of Metheringham they are full of soft tufaceous carbonate of lime, probably derived from the Boulder Clay. Eastward of Nocton Hall there are several shallow sand pits, capped in places with soft sandstone, which is crowded with ill-preserved specimens of Gryphesa bilohata and Belemnites. Similar beds are seen in a little pit half a mile northward of these, and there is a ploughed-down pit in the same south of the Potter Hanworth brook. Beyond this, the beds are concealed by Drift for two miles, and then the sands appear on the road three-quarters of a mile west of "The Green Tree." Half-a-mile eastward of Cherry Willingham, a deep ditch gives a fine section of bright yellow and tawny sands, and these are also seen in the railway cutting at the west end of the village, and on the slopes of the valley above and below Reepham. Mr. Cameron has noted the Kellaways Rock on the top exposed in the road north of the station. The escarpment continues to Sudbrook Holme, north of which the sands and sandstone were well seen in draining near Scothern Mill, in 1882. The black clay-shale at the base of the series is seen in the brook at Scothern, and in the two Cornbrash pits at Dunholme, above which village the road to Snarford shows several feet of fairly massive rock. Near Rutton aU the members of the series are seen in isolated sections ; the basement clay in a gravel pit, a quarter of a mile south of Rutton ; the sands opposite the mill ; and the rock in the stream east of the mill. The clay is again seen under gravel 200 yards north-west of Rutton, and at intervals in the bed of the main stream, the left bank of which is the well-marked escarpment of the sands, which continues to Saxby without other exposure than that furnished by shallow ditches. The basement clay extends up the dip-slope of the Cornbrash for a quarter of a mile along the road north-east of Hackthom Grange. W. H. D. Near Saxby the Kellaways Beds are generally sufficiently well indicated by surface soil and feature to be traced with jtolerable facility. They consist of sands which have, through the cementing matter of patches or lines of Belemnites and Gryphasce, been concreted into hard rock in places, very irregu- larly. From the preponderance of sand, which has no doubt been plentifully washed down its escarpment slope, we cannot be certain of its base within a few feet. The junction of the Kellaways with the Oxford clay is slightly marked by feature north of Saxby, and at Owmby, and Normanby, but at Glentham it is obscured by Chalky Boulder Clay, and between Glentham and Sminhays two smaller patches of Boulder Clay conceal the junction. Kellaways Rock is exposed by the road from Saxby to Spridlington, at about 12 chains from the former, and Kellaways Sand is shown a little further south. At the bend in the road, just north of the turnmgs to Spndhngton and Saxby, near the former, Kellaways Rock is visible in a ditch. About Owmby, Normanby, and Caenby, the Kellaways seems to consist almost entirely of sand, but I am told that about 18 inches of shelly rock has sometimes been encountered on sand in draining the land in the vicinity of Caenby Old Hall. Kellaways Sand covers the surface on the north of 76 MIDDLE AND TIPPER OOLITES. Glentham ; it is exposed in several places. At a mile and a quarter from Glentham Church, in a direction N. 15 E., Kellaways Rook is exposed in a ditch. On the south side of the road to the Ancholme, at a mile east from Bishops Norton, the JKellaways Sand is exposed to a depth of 54 feet in a sand-pit. I'he section is as follows : — Surface soil, brownish sand mth occasional bits of flint. Kellaways Sand, buff and ochre-coloured sand, mottled with pale greenish hues, ferruginous in places, and exhibiting a tendency towards lamination. In the upper part of the sand, just under the surface soil, there are two masses of Kellaways Rock, one of them being very small. Water is held up by the bottom of the pit. Kellaways Rock is better developed from this pit northward. The rock is exposed at the turning towards Harlam Mill, in the roadside ditch, also in a drain cutting across the Kellaways dip-slope west ; from the turning, Kellaways Sand is visible by the road near Srainhays, on the south and south-east. Near the road opposite the turning to Snitterby, Kellaways Rock, with the usual fossils, Gryphcsa bilobata and Belemnites (which, it should be mentioned, occur in all its exposures), is exposed to a depth of two or three feet in a pit. The rock is also exposed on either side of the road to the Ancholme south-east of the pit, and by the Ancholme Alluvium at the northern margin of Sheet 83. The common Gri/phaa bilobata and Belemnites are never found in quantities, and, even individual specimens are rare in the Kellaways Sand. They abound in the Kellaways Eock, which isj as we have seen, far more prevalent within a mile and a half from the north margin of Sheet 83 than further south. This character is maintained in Sheet 86 on the north, where the irregularly associated sands were regarded as Drift, until the survey of the area to the south showed the true nature of the Kellaways. W. A. E. U. Oxford Clay. The area occupied by this clay was surveyed by MesSrs. Ussher, Dalton,' Cameron, and Jukes-Browne ; and the following description has been compiled from the notes obtained by each. The Oxford Clay is a thick-bedded dark-blue shale, losing its lamination, jointing, and colour, when exposed to atmospheric influences, and becoming a soft plastic pale-yellow clay. From the quantity of iron pyrites which it contains, either in nodules or disseminated through the mass, the weathering of the slopes of railway cuttings or abandoned pits proceeds but slowly, the acidity produced by oxidation of the pvrites checking vegetation, and its concomitant action on the subsoil by the penetration of roots, so that a slope of bare shale, comminuted on the surface by the mechanical influences of frost and drought, is only converted into clay by the ultimate lixiviation of all acid and the development of vegetation over its surface. The chemical action is promoted by the presence in percolating and surface water of bicarbonate of lime, derived from the generally present Boulder Clay. This, changing by mutual decomposition with the ferric sulphate to gypsum, diminishes mechanically the impermeability of the first-formed clay, whilst the oxidation of the OXFOKD CLAY. 77 ferric carbonate to pei-oxide, and the reversal ami repetition of tlmt process by the alternate excess and disappearance of organic matter has probably a similar effect, admitting the access of the atmospheric agents to an interior layer of the mass. W. H. D. The following notes describe such exposures of the Oxford Clay as have been observed in Sheet 83, commencing at the southern border, nearTimberland. A large brickyard, half-a-mile norbh-east of TJmberland Church, exposes about 6 feet of (Jxford Clay beneath the Fen and Drift Deposits ; the section here seen by Mr. Jukes-Browne in 18/8 beinpf given on p. 171. The Oxford Clay is of a dark slate colour, and contains many fossils Gnjphcea dilatuta and the small Ammonites being scattered about the floor of tlie pit in abundance. The following were collected : — Grypheea dilatata, Sow. Belemnites, sp. Ammonites Lamberti, Sow. A. Maria, D'Orb. A. oculatus, Phil. Still lower beds are seen in the trenches along the railway east of Scopwick and Blankney, and in a brickyard on Cottagers Common, but the excavations are only shallow. North of this the Oxford Clay is gi-eatly obscured by drifts, and nothing but ditch-sections were found on the west side of the Witha.in Fens. On the east side of these^Fens-l^ Upper Oxford Clay sets in near Bardney, and is exposed for som§,40 feet in the large brickyard near the Station. It is a stiff blue clay, contei'ning the following fossils, identified by Mr. Sharman : — Ichthyosaurus (veraebra). Ammonites cordatus, Sow. Ammonites perarrn^us. Sow. „ excavatus. Sow. A. biplex, Sow. \ „ plicatilis, Sow. A. macrocephalus, Sphloth. Grypheea dilatata. Sow. A. arduenensis, D'Orb. Serpula sulcata, Sow. The same beds, with Armn- perarmatus, were found in the valley near Rand, about five miles to the northward. A. J. J.-B. Mr. Dalton continues the description as follows : — Lower beds are seen in an old brickyard near the east end of Fiskerton Long Wood, and from thence in ditch-sections to Fiskerton. There are casual exposures in the hollows north and south of Larigworth station, and here and there near the outcrop of the Kellaways Beds to Spridlington. The clays dug in the Langworth Bridge brickyard contain Ammonites Lam- herti axid Grypheea dilatata ; similar clays were seen in various ditch-sections about Scothern Grange, and constitute the base of the slopes of the Langworth valley northwards of Swinthorpe. They are worked for bricks at Snarford Hill, and were worked formerly a quarter of a mile east of Fristhorpe. Besides frequent but unimportant ditch-sections, the only notable exposures are in a gravel pit a mile west of Wickenby station, and the deep drains in the flat clay lands east of Cold Hanworth, which show the weathered clay on their banks and (at the periodical clearings) the unaltered blue clay in their wide floors. Half a mile west of East Firsby there is an old brickyard with Oxford Clay, which is also seen in the brooks and ditches hereabouts. In all these places, Gryphaa dilatata was observed, but no other fossils were obtained. W. H. D. Mr. Ussher, in describing the northern part of the Sheet, remarks : — North of Spridlington the Oxford Clay on the west of the Ancholme Valley is to a great extent concealed by Chalky Boulder Clay ; the largest tract formed of it superficially is near Bishops Bridge. At half a mile east of Normanby (by Spital) Church, a brick-pit about 180 yards long from nortli to south, exposes Oxford Clay to a depth of from 3 to 78 MIDDLE AND UPPT:E OOLTTEP. 5 feet ; the clay is stiff and bluish-grey mottled, or marbled, ^vitll buff or brown ; it is capped by pockets of reddish-brown sandy matter and grey clay with small angular flints under about a foot of drab soil. At the bend in the high road to Glentham, near Bishops Bridge, a well was sunk in 1883 in the Oxford Clay. For about 6 feet down it was mottled, or marbled, with yellowish brown or buff tints ; below that, it consisted of dark grey rather shaly clay from which the following fossils, in a pyritized condition, were obtained. Nucula? sp. A. Duncani, Sow. Ammonites plicatilis, Sow. A. Lamberti, Sow. A. hecticus, Rein, var. canaliculatus. Grey and brownish Oxford Clay is exposed in the drains on the flattish tract extending in a north-easterly direction from the well. A mile from Glentham Church in a direction N. 30 B., Chalky Boulder Clay is shown in a pit, resting on Oxford Clay ; the latter consists of bluish-grey clay mottled yellowish- brown, and exhibiting a shaly splitting tendency, and cutting like cheese. The same texture is exhibited by the clay exposed at 8 chains south of the pit, where stiff bluish and chocolate-brown clay was proved to a depth of 2\ feet under superficial sand. At about a quarter of a mile north-west from the pit above mentioned, about a foot of grey clay was observed in a ditch, resting on yellowish sand ; it is over- lain by sandy soil with flints. As it occurs where the junction of the Oxford Clay with the underlying Kellaways Rock should be, it has been taken as evidence of the position of this boundary. By the road toward Harlam Mill, at a mile and three-quarters east of Atterby, laminated bluish-grey Oxford Clay is exposedin a brick-pit under a Drift soil. .^'"^''^ix The junction between the Oxford Clay and KellsBMys Rook, when not concealed by Boulder Clay, as north of Glentham and east of Bishops Norton, is usually marked by feature, breaking or diversifying the slight dip-slope of the Kellaways Rock. W. A. E. U. Kimeridge Clay. As already stated (p. 73), there is a complete passage from the Oxford into the Kimeridge Clay, making it difficult to draw any line of division between them. The boundary shown on the map has been drawn along a strip of country between the places where either clay can be identified with any certainty. Near Bardney the position of this zone of passage can be fixed with tolerable certainty for there are two brickyards within little more than a mile of each other, one of which, as already men- tioned, contains Oxford Clay fossils ; while the other yields species characteristic of Kimeridge Clay. Hence the passage beds must run along the strip of country between them. North of this, the line of junction is entirely hypothetical,- as no open sections have been observed anywhere near it, except at Rand, where Ammonites perarmatus indicates Oxford Clay. Dark clays with large septaria containing serpulse were observed in small field-pits between West and Middle Rasen and at Osgodby, but no depth was exposed. The brickyard south of Osgodby Mill must have given a section of these passage beds, but is now abandoned and overgrown. Prof. Blake, however, examined the spoil from a well-sinking on the main road near here, and found " black clays with white rotten fossils in layers, most of them being undistinguishable, but Gryphcza dilatata and Belemnites were plentiful;" he also obtained a reptilian bone bearing a KIMEETDOE CLAY. 79 specimen of Dtscina humphresiana, and he remarks that the Belemnites were not hastate, but comparable with B. nltidus. He regards these clays as identical with those seen in the railway cutting west of Wrawby in Sheet 8G. From the collections made by Prof. J. F. Blake and by the Survey fossil collector, it would appear that the Kimeridge Clay may be divided into a lower and upper portion, the former in- cluding the great mass of the formation. The Lower Kimeridge Clay contains many species which are usually considered as Oxford Clay forms, such as Ammonites plica- tilis and Gryphma dilatata ; but this mixture of species appears to be greater in the north of Lincolnshire than In the south part of Sheet 83 ; but throughout the county, Lingula ovalis, Thracia depressa, and Ostrea deltoidea may be taken as evidence of the beds containing being Kimeridge Clay. The upper portion of the clay consists of grey and black shales, with layers of limestone doggers, sometimes forming continuous floors of poor hydraulic limestone. Some of the shales are bitu- minous ; others are grey, dry, and papery. Lower Kimeridge. The lowest beds are exposed in a brickyard about a mile south-east of Bardney Church. They consist of black shales, about 13 feet of which are seen below the superficial deposits, and they have yielded the following fossils ; — Belemnites Owenii, Pratt." Thracia depressa, Sow. B. abbreviatus, Miller. Cucullaa longipunetata, Blake. Ammonites, sp. Astarte supracorallina, D'Orb. Spinigera, sp. Avicula, sp. Dentalium (? Quenstedti). Head of Fish.* In a drain near Campney, Ammonites plicatilis, Am. muiabilis, a,nd Am. rotundus were found. Further south-east, between Stixwould and Woodhall Spa, and about G fur- longs from the latter, is a brickyard, now closed, but open in 1871 when the following section was taken by Mr. Skertchly : — Ft. Superficial / Sand, false-bedded, with a few pebbles - - 1 1 Deposits, t Fine gravel - - - - - 1 r Soft dark-blue clay - - . . (i Kimeridge J Line of septaria full of serpulas - - 1 Clay. I Soft dark-blue clay . . G L Course of septaria. Mr. J. F. Blake records the following fossils from this pit : — Belemnites nitidus, Dollf. Ostrea deltoidea. Sow. Ammonites serratus. Sow. Lima cedilignensis, Blake. Rissoa mosensis, Buv. Thracia depressa, Sow. Avicula adilignensis, Blake. Area, sp. Cyprina cyreniformis, Blake. Serpula teiragona. Sow. Some of the above-mentioned species were also found by Mr. Blake in a small pit near Hawstead Hall, north-east of Stixwould. No exposures are to be found for some distance to the eastward, the next being a brickyard near Langton, west-south-west of Horneastle; the clay here contains large ferruginous concretions, and the fossils found by Mr. Blake * Obtained &om the workmen by Mr. Cameron. 80 MIDDLE AND UPPER OOLITES. are given in the Table (Appendix, p. 191). It is noticeable that Ammonites serratus still occurs at this horizon, but is not found at the Horncastle pits mentioned below. At Horncastle there are three brickyards, one south of Thimbleby House, on the west side of the Bain, and two deep pits on the east side of the valley nearer the town. The Ammonites are A, hiplex and A. mutabilis, and the rest of the fossils obtained here by Mr. Blake are given on p. 191. In traversing the ground between Bardney and Horncastle, the observer will have passed over the greater part of the Lower Kimeridge Clay. The sections to the north of this line will now be noticed. The first is a brickyard on the Wragby road, one mile and a half W.N.W. of Baumber. Mr. Strahan describes this as dug in laminated shale, with numerous flattened septaria, ranging up to 44 feet in diameter by about 1 foot in thick- ness ; there are also hardened masses of clay traversed by threads or films of a whitish mineral (? selenite), enclosing a calcareous nucleus. The commonest Ammonites are : A. Berryeri and A. serratus, and the shales must be on about the same horizon as those at Langton. For other fossils see Appendix, p. 191. Mr. Strahan remarks that the valley of the Bain, from Baumber to Benni- worth has gently-sloping sides of Kimeridge Clay, in which pits have been opened in former times for obtaining clay to spread on the land. These pits are now overgrown, and full of water. Nearer Wragby, and five furlongs W.S.W. of Hatton, is another brickyard, which was visited by Mr. Cameron, who found about 4 feet of black shaly clay exposed beneath the superficial deposits ; the clay contains calcareous concretions, and the following fossils were obtained :^ Ichthyosaurus, sp. (vertebrae). Belemnites abbreviatws. Mill. Pliosaurus, sp. (paddle). Pleurotomaria reticulata, Sow. Ammonites rotundus, Sow. Inoceramus, sp. A. alternans, Buch. Ostrea, sp. The next exposures are those near Market Rasen. In the railway cutting, south of the town, Mr. Strahan found laminated clay, with Ammonites muta- bilis, A. rotundus, and A. alternans. At the brickyard three-quarters of a mile east-south-east of the church, the section is as follows : — Ft. Clean yellow sand, current-bedded (moor sand) 7 Dark bluish-black clay, shaly when dry 16 Course of hard calcareous rock - - - - 0^ Dark clay below (according to workmen). This pit has long been celebrated for the beauty and variety of the fossils found in it ; most of them occur just above the band of rock, but calcareous concretions occur throughout, and many of these contain Ammonites. For full list see p. 191. Another pit, half a mile north-east of the church, shows a similar section. Here Mr. Strahan obtained the following fossils : — Ammonites alternans, Buch. Lmcina, sp. ,, rotundus. Sow. Thracia depressa, Sow. „ tripUcatus, Sow., var. ? Inoceramus, sp. On the flanks of Hamilton Hill there are old pits, showing blue clay with septaria and fragments of fossils, but the sections are ob'^cured by slipping. Mr. Blake, however, records the following fossils from this locality, and considers it to be a higher horizon than the pits above mentioned ; — Ammonites Berryeri, Les. Avicula nummulina, Blake. ,, biplex, Sow. Astarte supracorallina, D'Orb. „ yo ? D'Orb. RhynchoneUa pinguis, Eom. Nucula obliquata, Blake. There is another brickyard (not now worked) by the Caistor road, a mile and a quarter north of Market Ilasen ; here many of the same Market Rasen fossils were found by Mr. Blake.* * See Qiirir/. .fount. Geol. Soc, vol. xxxi., p. 209. KIMERIDGE CLAY, 81 Upper Kimeridge. This division enters the sheet to the north-east o£ West Ashby, and the blue clay seen beneath Boulder Clay in the pit marked " kiln " on the map, one mile north-east of Ashby, probably belongs to it. It is much better exposed in a brickyard at Goulsby (one-third of a mile south-south-east of the church), where Mr. Blake saw the following section ; — Ft. In. Papery shales - - - - - -09 Blue dicey clay - - 3 4 Harder fossiliferous band - - - 1 6 Blue clay, with nodules at the base - - 110 19 7 The fossils obtained here were : Ammonites biplex, Lucina minuscula, Ostrea gibbosa, Discina latissima, and Belemnoteuthis antiguus (?) ; the surfaces of some of the shales being crowded with the small bivalves. The railway cuttings near South Willingham are now completely obscured. Mr. Blake gives the following section as seen in one of them : — Ft. In. Thin limestone band - - - - 4 Blue shale - - - 9 Band of hydraulic limestone - - - - 8 Light blue dicey clay - - From the limestone he obtained Ammonites pectinatus, Lucina minuscula^ Ostrea gibbosa, and Discina latissima. A. J. J.-B. Of the kiln near South Willingham Station, Mr. Strahan supplies the following account : — The blue clay used for bricks extends to a depth of about 8 feet in the present working (1882). At its base it is full of very large septaria, averaging from 3 to 4 feet in diameter, by about H feet thickness These septaria break up readily in the weather ; the outer portions consist of a blue argillaceous limestone of an earthy texture, traversed by cracks filled, or partly filled, with dogtooth caloite ; in the centre is a heart almost entirely made up of calcite. This limestone was sent to Hull to be tried for hydraulic cement, but proved worthless. Below the layer of septaria there occur bands of a hard inflammable oil shale, locally known as " dice." The bands are 4 to 6 inches thick, and are separated by blue clay. Fragments of dice readily blaze when dry, and leave a copious grey ash, giving off a most offensive smell while burning. It is said that the clay from this pit, when made up into bricks and ignited in the kiln, to a certain extent supports combustion, giving off a poisonous vapour that is highly prejudicial to vegetation. About Willingham water is got in some of the shallow wells from the beds of dice. Some of the water is ferruginous and smells offensively. No other sections were noted in these beds, except a pit north of Claxby, showing dark shales, with a Jiard stony band 12 to 16 inches thick, and containing Ammonites biplex, Ostrea deltoidea, and small bivalves. The appearance of the Kimeridge Clay, and the fact of its coutaining bands of inflammable shale, has led to the useless expenditure of large sums of money in boring for coal. A boring was made by Mr. Bogg in the neighbourhood of Donnington to a ^epth of 103 yards, with no further result than proving blue clay, argillaceous stone, and thin bands of inflammable schist (dice).* In 1819 an equally useless attempt to find coal was made at Woodhall ; a shaft was sunk to a considerable depth, and a boring was carried to a total depth from the surface of 1,020 feet, with the result of tapping a saline spring, which has since proved of medicinal value.t The bands of inflammable shale probably run through the whole district, but are very rarely seen from want of good sections. It may be mentioned here that similar beds occur in the Kimeridge Clay on the Dorsetshire coast, and have been mined by levels driven into the cliff. ' A. S. * See Appendix, p. 202. t See Appendix, p. 205. i 50058. F ^2 LOWEp C&ETAOBOUS ROCKS. CHAPTER X* LOWER CRETACEOUS OR NEOCOMIAN ROOKS. Classification. The Neocomiau Rocks run diagonally across the north-eastern corner of this Sheet at the foot of the Chalk escarpment. Though extending over wide areas in Sheet 84, they become restricted in the northern part of the present map to a very narrow strip, partly in consequence of a steady northerly attenuation of all the beds {see Plate), and partly through the increasing steepness of the slope in which they crop out. The various subdivisions succeed one another rapidly in this slope, yet each presents an easily recognisable feature. Further north the Neocomian series is lost to view, partly through an unconformable overlap by the Upper Cretaceous rocks, but principally through the continued thinning away of the beds themselves. While thus unconformably overlapped, they them- selves rest unconformably on the Kimeridge Clay. A glance at the map will show this better than a verbal description ; the Neocomian beds, striking north-east, gradually approach the escarpment of Lower Oolites, which runs nearly due north and south, and, as they do so, overlap towards the north nearly the whole of the great thickness of Kimeridge Clay that underlies the neighbourhood of Horncastle in the south. A detailed examination of the beds themselves confirms the opinion that these overlaps are attributable to erosion of the Neocomian beds in the one case, and of the Kimeridge Clay in the other, and not merely to a thinning out of these beds without unconformity. The Carstone is found to be made up very largely of the rolled and washed debris of the Neocomian clays, or, where the Carstone is missing (Sheet 86), the Red Chalk is found to contain fossiiiferous nodules derived from the same source.f The base of the Neocomian beds again is found to be a nodule bed, with numerous rolled casts of fossils, many of which can be identified as having been derived from the Kimeridge Clay. In both cases, therefore, there is evidence of erosion having taken place. The beds intervening between these two lines of erosion, and known as the Speeton Series, form a very distinct group, distinguished both palaeontologically and lithologically from the Carstone above and the Kimeridge Clay below. In spite, however, of this evidence, it has been decided to retain the Carstone in the Neocomian group with the Speeton Series, prin- cipally because of the strong reasons for correlating the Carstone with a part of tlie Lower Greensand of the south-east of England, to which the name Upper Neocomian has been applied. The classi- fication that has been, and is now proposed, will now be discussed. * Written, except where otherwise noted, by Mr. A. Strahau. t Notes on the Relations of the Lincolnshire Carstone, by A. Strahan. Quail, Journ. Geol. Soc, vol. xlii. pp. 489 and 491, 1886. NKOCOMIAN. 83 The most complete accounts of the Lincolnshire Neocomian that have yet appeared are by Professor Judd* In the first of these communications, after describing the Red Chalk, he gives a detailed account of the beds under the following names : — The upper ferruginous sands (probably representing the Norfolk Cars tone). The Tealby Series, consisting of sandy clay and limestone. The Lower Sand and Sandstone. He considers that the upper ferruginous sands are uuconformably overlaid by the Hunstanton Limestone (the Red Chalk), his evidence of this being the fact that they, in common with the underlying beds, arc overlapped towards the north by this rock ; the Tealby series is referred to the Pecten cinctus zone or Middle Neocomian of the Speeton section, the Lower Sand and Sandstone bemg of doubtful relationship. In 1870 he correlated these subdivisions with those which have been made in other parts of the north of England and of northern Europe, and constructed a comparative table for the North of Europe, of which the two first columns are here given :- YORKSHIKE. LtNCOLNSHIKK. GauIt(Albien,X)'0)-6.) Hunstanton red-rock Hunstanton red-rock. Unconformity. Upper Neocomian f (Aptien, LfOrb.;] Rhodanien and ] Aptien, Rencv. - I 1 ? Ft. Black clays I Dark blue clays ]■ " ^^° " Cement beds " - 30 ITpper Sands ? Middle Neocomian (Urgomen,X>'Ori.; Barremien and' Urgonien, Coq.) - Dark blu e clay s, with few fossils 80 (" Zone of Pecten cinctus.'") Blue clay, with fossils - - 40 (" Ancifloceras beds.") Clays, with septaria 80 "Tealby Seiies." Clays, limestones, and oolitic iron- stones, with many fossils. Lower Neocomian (N^ocomjen, D'Orb.; Blue clays - - - 100 (" Zone of Am. speetoneiisis.") Blue clays - 50 (" Zone of Am. noricus.") Blue pyritic clays - 50 (" Zone of Am. asterianus."') Valanginien and Neocomien, Defor.) Lower Sands and Sandstones ? Tithonien, Oppel. Unconformity. Jurassic Portlandian Clays, &c. Kimeridge Clay. * On the Strata which form the Base of the Lincolnshire Wolds. Quart. Journ. Geol. Soc, 1867, vol. xxiii.,pp. 227-251. _ Additional observations on the Neocomian Strata of Yorkshire and Lincolnshire, with Notes on their relations to beds of the same age throughout Northern Europe. Quart. Journ. Geol. Soc, 1870, vol. xxvi., pp. 326-347. See also On the Speeton section, (^Quart. Journ. Geol. Soc, 1868, vol. xxiv., p. 218), where it is shown that the Blue Clay, 40 feet thick, and the clays with septaria are the zones of Pecten cinctus, and of Anoyloceras respectively. ¥ 2 84 LOWER. CRETACEOUS ROCKS. It will be seen that the Upper Sands, though doubtfully corre- lated with the Upper Neocomian, are definitely included by Professor Judd with the Speeton beds in the Neocomian series, and that an unconformity is considered by him to exist between them and the Red Chalk. In Lincolnshire, however, the Carstone contrasts strongly with the Tealby Series in lithologjcal character, and in being com- pletely iinfossiliferous. While, moreover, there are no signs of erosion at the base of the Red Chalk, though its junction with the Upper Sands is repeatedly exposed, there is reason to think that considerable erosion of the Tealby Beds had taken place before the deposition of the Upper Sands, the evidence for this consisting in an overlap, and in the fact that the Upper Sands are made up principally of materials that appear to have been derived from the Neocomian clays. The evidence of unconformity derived from overlap is not very satisfactory, inasmuch as the overlap takes place at more than one horizon, from the persistent thinning of all the beds north- wards {see Plate) ; the following series of thicknesses, taken in order from south to north, will illustrate this : — n3 « 8| 03 1 c3 ^ tr. 1 ^ £ .5 O CO H O < fe <1 s E^ Ft. Ft. Ft. Ft. Ft. Ft. Ft. Ft. Ft. Red Chalk - n 6 6 5 ? 4 4 1 3-4 Upper Sands (or Car- 40 25 - 20 14 10 8 stone). Tealby Beds 135 65 60 (about). 60 68 20-40 10 1-3 Lower Sands (or 50 42 36 30 (?)?* 35 15 9 10 Spilsby Sandstone). (about). (about). As the Tealby Beds become reduced from 135 to 20 feet before the Carstone finally disappears, the argument for an unconformity as derived from an overlap is as applicable to the top of the Tealby Beds as to the top of the Upper Sands. The palajoutological evidence is of more significance. It may be at once stated that there is good reason for correlating the Lin- colnshire with the Hunstanton Carstone. Lithologicidly the rock is identical, and in each case underlies the Red Chalk in a manner that leaves no doubt that it is the same bed. The age of the Hunstanton Carstone has been determined on the strength of certain fossils which occur in nodules near the base of the rock. These were first observed by Mr. Wiltshire, who correlated the portion of the Carstone in which they were found with the base of the * Thickness as given in copy of the sinking journal of a shaft at th« iron-mine ; there appears to have been a mistake made, as the sand at the outcrop close by is of tho normal thickness NBOCOMIAN. 85 English Lower Greensand.* The whole fauna, however, is re- garded by Mr. Keeping as derived,t a conclusion which makes the Hunstanton Carstone later than those Neocomian rocks of Lincoln- shire, in which the fossils are indigenous. The following is the list of specimens collected for the Woodwardian Museum, as given by Mr. Keeping : — Perna Mulleti (some of them derived, but some looking like natives) ; Pleurotomaria : Ammonites Comuelianus, Forbes ; Ammonites Martini, Forbes ; Ammonites Deshaysii, Leym. ; Ammonites, sp. ? (aUied to Kanigi); Ammonites, sp. ?; Ancyloceras gigas. Sow.; Ancyloceras (tuberculated species); Nautilus, sp. Further than this, in the Hunstanton Carstone there occur masses as large as cannon balls of a dark-coloured grit rock, containing a special fauna. From a careful study of the contained fossils {op. cit., p. 34), and of their lithological character, Mr. Keeping concludes that these blocks " are all of Neocomian age, having been derived from a deposit closely connected with that of the Lower Neocomian sands of Lincolnshire, whose loose sandy materials being removed, the harder masses were left " (op. cit., p. 37). The same rock is found in precisely similar condition in the Upware and Potton deposits. Specimens of the blocks from the Hunstanton Carstone may be seen in the Woodwardian Museum. Reference has been made previously to the fact that the Lincolnshire Carstone is made up largely of the debris of Neo- comian clays (Tealby Beds). . It contains vast quantities of small well-rolled pebbles of a pale yellow or brown phosphate, with occasional lines of large nodules of similar substance containing Neocomian species. Among these the following have been noted by Mr. H. Keeping as occurring in pebbles in the Carstone at Ciaxby, about 5 feet below the base of the Red Chalk: — Ammonites Deshaysii (Leym.), Am. biplex (Sow.), Requienia ? Astarte sp., Corbula, Modiola, Myacites, Pholadomya, Cyprina, Teredo. At Otby there were obtained during the present survey i — Ammonites speetonensis (?) four specimens. Am. plicomphalus (?) one specimen, Lucina (?), and others, and a gasteropod, all from well-rolled phosphate pebbles. The smaller materials of which the Carstone is composed, consist of quartz sand and small rounded quartz and Lydian-stone pebbles, such as occur in the Lower Sands and Sandstone ; and of small flakes and grains of iron- oxide that appear to have been derived from the clays and iron ores of the Tealby Beds. The Lincolnshire and Norfolk Car- stones have, therefore, this properly in common, namely, of containing abundantly fragments, or washed debris, of some portion or other of the Speeton Series. But in Norfolk the Carstone rests directly on the Kimeridge Clay, and must, therefore, be either considered to be partly representative of the Speeton Series, or this series must be * Quart. Jourii. Geol. Soc, vol. xxv., p. 189, 1869. + The Fossils and Palasontological Affinities of the Neocomian Deposits of Upware and Brickhill, by Walter Keeping, M,A., F.G.S., 1883, p. 32. 86 LOWER CRETACEOUS ROCKS. supposed to be absent altogether. In discussing the first of these suppositions, it may be mentioned that there occurs a thin and impersistent band of clay in the Norfolk Carstone which at first sight might be taken to represent the Tealby Beds, the sand (or portion of Carstone) beneath it then representing the Lower Sands and Sandstone. But the accompanying table of com- parative sections {see Plate) shows that the Tealby Beds are thickening in the direction of Hunstanton, when last seen in Lincolnshire. For example, from Nettleton to near Belchford, a distance of about 16^ miles, these beds thicken from 30 to 135 feet, and in the Skegness boring (Sheet 84) had increased to 219 feet. _ It is, therefore, very improbable that they should thin out in the next 16 miles which separate Skegness from Hunstanton*. The details of the Norfolk section, moreover, do not correspond to the subdivisions which have been found so constant in the Tealby Beds in Lincolnshire. On the second of these suppositions, namely, that the Speeton Series is wholly unrepresented in Norfolk, f an explanation of their absence is found in the evidence of unconformity between them and the Carstone that has been obtained in Lincolnshire. It must be supposed that the series was wholly denuded away from the Norfolk and adjoining areas of Bedfordshire and Cam- bridgeshire, before the Carstone was deposited. This implies that the denudation was greater on the south than the north side of the Wash, a conclusion which is borne out by a study of the included fragments of Neocomian Rocks that occur in the Carstone in different areas. In Lincolnshire these consist of nodules, &c. derived from the Tealby Beds ; at Hunstanton of the same with the addition of boulders of Lower Neocomian Sandstone; and further south again of boulders of this sandstone, with the addition of a very large proportion of derived Kimeridge Clay fossils, and a smaller number of Portlandian and Oxford Clay forms, while a few only of Neocomian species are found. Similarly, towards the north of Lincolnshire, where the Eed Chalk in the absence of the Carstone becomes conglomeratic (see Plate, sections 2 and 3), the fragments include specimens of older and older rocks, on approaching the area of upheaval which separated the Yorkshire and Lincolnshire basins in the Neocomian period, and in which older rocks are successively brought into contact with the base of the Upper Cretaceous beds. The Hunstanton Carstone has been generally correlated with the Upware deposits and with the Neocomian rocks of Bedfordshire and Cambridgeshire. It follows then that these rocks also are later than the whole of the Speeton Series, and of the Tealby Beds of the Lincolnshire section. In the south of * It is suggested by Mr. Jukes Browne that there may he unconformity at the base of the upper or Hunstanton Carstone, which would provide an explanation of the comparative thinnes.s of the underlying clay in Norfolk. He considers the lower Norfolk sand to be more like the Spilshy Sandstone than the Carstone. t It was stated as his opinion by Professor Judd, in the year 1869, that the Car- stone of Norfolk does not represent the Tealby Beds. On the Eed Chalk of Hunstanton, Wiltshire, Quail. Joiini. Geol. Soc, vol. xxv., p. 192 (Discussion). NEOCOMIAN. 87 England, however, there seems little doubt that there are equiva- lents of the upper portion at least of the Speeton Series. The fauna of the Atherfield Clay presents the closest analogy with the Upper Neocomian of Speeton acfording to Professor Judd, while the horizon of the Upware phosphate-beds, and of the lower beds of the Hunstanton Carstone is fixed by Mr. J. Meyer at that of a pebble-bed near the base of the Folkestone Beds. Tlie supposed correlation with the south of England is added to the table given subsequently (p. 88). We have now to face the difficulty of fossils of Neocomian species having been found indigenous in beds which, as we l)elieve, have been made up from the waste of Neocomian rocks. The indigenous and derived faunas have been frequently confused, and are even now only partly distinguished, but enough has been done to prove that the Upware and other homotaxial deposits contain a large number of indigenous Neocomian (Aptien) species. We have, therefore, an unconformity between the newest Neocomian (Carstone) and the older Neocomian (or Speeton Series). In at- tempting to account for the presence of late Neocomian