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 ^*^nimmm?^ °' Eastern Berwickshire.(Map 
 
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34 SCOTLAND. 
 
 MEMOIRS 
 
 OP THE 
 
 GEOLOGICAL SURVEY 
 
 OF 
 
 GREAT BRITAIN, 
 
 AND OF THE 
 
 MUSEUM OF PEiCTICAl GEOLOGY. 
 
 THE GEOLOGY OF 
 
 EASTERN BERWICKSHIRE. 
 
 (Map 34.) 
 
 BY ■ ,';;;j,.,.' 
 
 AECHIBALD GEIKIE, F.K,S, ^3^^ F.G.S. 
 
 rVDLISHED BT OBSEB OS IBS LOBDS COMMISSIONEItS OF HEK UAJESIT's IBEASUKT, 
 
 LONDON: 
 
 PRINTED POE, HER MAJESTY'S STATIONERY OKFICE : 
 PUBLISHED BT 
 
 LONGMAN, GKEEN, LONGMAN, ROBERTS, AND GREEN. 
 
 1864. 
 
 /Wee 2s, 
 
NOTICE. 
 
 The Session of the Government School of Mines and 
 of Science applied to the Arts Commences early in October 
 in each year, during which the following Courses of 
 Lectures are delivered : — 
 
 Chemistry, with special reference to"| 
 
 its applications in the Arts and >A. W. Hofinann, LL.D., F.B.S. 
 
 Manufactures - - J 
 
 General Natural History - - T. H. Huxley, F.R.S. 
 
 Physics - - ' - - John Tyndall, Ph. D., F.R.S. 
 
 Applied Mechanics - - , - Robert Willis, M.A., F.R.S. 
 
 Metallurgy - - - John Percy, M.D., F.R.S. 
 
 Geology - - - - A. 0. Ramsay, F.R.S. 
 
 Mineralogy- - - . | WaringtonW. Smyth, M.A., 
 
 The Chemical Laboratory, under the direction of 
 Dr. Hofmann, and the Metallurgical Laboratory, under 
 the direction of Dr. Percy, are open for the instruction of 
 Students. 
 
 A Prospectus and Information may be obtained on 
 application to 
 
 Trenham Reeks, Registrar. 
 Jermyh Street, London^ S. W. 
 

34 SCOTLAND. 
 
 MEMOIRS 
 
 OF THE 
 
 GEOLOGICAL SUEVEY 
 
 OP 
 
 GREAT BRITAIN, 
 
 AND OF THE 
 
 MUSEUM OF PIUCTICAL GEOLOGY. 
 
 THE GEOLOGY OF 
 
 EASTERN BERWICKSHIRE, 
 
 (Map 34.) 
 
 BY 
 
 ARCHIBALD GEIKIE, F.E.S. Edin., F.G.S. 
 
 PTJBtlSHED BY ORDEK OF THE LORDS COMMIESIOHEES OF HEE MAJES.Ty'S TREASURY. 
 
 LONDON: 
 
 PRINTED FOR HER MAJESTY'S STATIONERr OFFICE: 
 PnBLISHED Br 
 
 LONGMAN, GREEN, LONGMAN, ROBERTS, AND GREEN. 
 
 1863 
 
 6802. 
 
 "ij 
 
CONTENTS. 
 
 Pa£:e 
 
 Chapter 1. Physical Features of the District, and General Distri- 
 bution of the Rocks . - - 1 
 
 Chapter 2. Lower Silurian Formation 6 
 
 Chapter 3. Lower Old Red Sandstone - ; - - /- 20 
 
 Chapter 4. Intrusive Rocks in Lower Silurian and Lower Old 
 
 Red Sandstone Series - - - 28 
 
 Chapter 5. Upper Old Red Sandstone and Conglomerate , - 34 
 
 Chapter 6. Carboniferous Formation . - - - 41 
 
 Chapter 7. Igneous Rocks later than Upper Old Red Sandstone 
 
 and Carboniferous Formations — Faults - - 47 
 
 Chapter 8. Drift, Alluvium, Recent Marine Deposits - 50 
 
 Ai^PENDix — List op Fossils, by J. W. Salter, A.L.S., F.G.S. 
 
GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 (Sheet 34, Scotland.) 
 
 CHAPTER I. 
 
 Physical Features of the District and General Distribution of 
 
 THE Rocks. 
 
 The present Map represents a triangular portion of Berwickshire 
 occupying about 120 square miles'. This area extends along the margin 
 of the German Ocean from the village of Cockburnspath nearly to Ber- 
 wick-upon-Tweed, and advances inland along the southern base of the 
 triangle to the outskirts of the town of Dunse. It thus includes the 
 eastern extremity of the Lammermuir HUls, the undulating ground 
 between St. Abb's Head and the mouth of the Tweed, and a small part 
 of the northern edge of the great valley or " merse " of Berwickshire. 
 
 This proximity of high uplands to a rich agricultural plain gives rise 
 to considerable diversity in the physical features of the district. A Hne 
 drawn in a north-easterly direction from Dunse Law to the sea at St. 
 Abb's Head divides the Map into two nearly equal portions. That to 
 the north-west is the region of the Lammermuir HiUs, which plunge into 
 the sea along the range of precipitous cHffs between ther Siccar Point and 
 Coldingham. Hence it is only the north-eastern extremity of this range 
 of hills which comes within the limits of the present Map. The general 
 scenery of this portion however corresponds to that of the more westerly 
 parts of the chain. It consists of highly inclined Silurian grits and 
 shales, but nowhere rises to a height of more than between 800 and 900 
 feet above the sea. Its outlines are rounded and undulating, save where 
 fissured here and there by steep ravines. Wide heathy uplands stretch 
 away inland, sinking gently down into tortuous intervening valleys, but 
 with no determinate system, so that the chain is thus composed of number- 
 less smooth-backed coalescing ridges and hiUs. The surface of this hilly 
 ground is for the most part covered with heath and bent, and is used as a 
 pasturage for sheep. The narrow sequestered valleys are dotted with 
 solitary farmsteads where the adjacent slopes have been laid under the 
 plough, and the fields are now creeping further up the hill sides every 
 year ; but the whole district stiU retains its quiet pastoral character. 
 The portion of the Lammermuir chain embraced in this sheet is traversed 
 by two main valleys ; that of the Whiteadder Water, and that followed by 
 the line of the North British Railway. Of the vale of the Whiteadder in 
 its course across the hills only a small part is here represented, where the 
 stream, bending round and piercing the granitic mass of Cockburn Law, 
 issues from the high grounds at Preston, about two miles to the north of 
 Dunse. The valley in which the railway runs crosses the chain com- 
 pletely from side to side. Its summit level, forming the watershed of 
 the hills, in place of being a ridge dividing the sources of the streams, is a 
 flat peaty meadow from the margin of which the ground rises rapidly on 
 both sides. From this point the valley stretches to the south-east for 
 about a mile, where, at nearly right angles, it receives the Eye Water, 
 
 A 3 
 
4 GEOLOGY OF EASTERN BEEWICKSHIEE. 
 
 and then pursues its course until at the viUage of Ayton, this stream is 
 turned sharply to the north-east, and cutting a deep ravine across some 
 hilly ground reaches the sea at Eyemouth. The north-western contmu- 
 ation of this great transverse valley is the deep glen occupied by the 
 Pease Burn. This sti-eam for the Arst half of its com-se flows in a south- 
 easterly du-ection until it reaches the flat peaty meadow just referred to, 
 when, instead of contmuing in the same du-ection and jouiing the Eye 
 Water, it wheels round at an acute angle to the north, and enters the 
 ravine which reaches the sea to the east of Cockburnspath. This marked 
 defile ranges from 100 to 150 feet in depth, and is well known from 
 the ai-ch which crosses its seaward end, called the Pease Bridge. As 
 it lay across the ancient highway along the east coast between England 
 and Scotland,- it was always a pass of importance. Cromwell wrote 
 of it as " the sti-ait pass at Copperspeth,* where ten men to hinder 
 " are better than forty to make their way." Patten, a Londoner 
 who accompanied the Duke of Somerset's expedition into Scotland ua 
 1548, describes it as " a valley rumiing straight eastward and towai'd the 
 " sea, a xx skore broad from bank to bank above, and a v skore in the 
 " bottom, wherein runs a little river ; so steep be those banks on either 
 "'side, and deep of the bottom, that who goeth straight down shall be in 
 " danger of tumbling ; and the comer up so sm-e of puffing and pain ; for 
 " remedy whereof the ti-avellers that way have used to pass it, not by 
 " going directly, but by paths and footways leading slopewise, from the 
 " number of which paths, they call it (somewhat nicely indeed) the 
 « Peaths." 
 
 This remarkable ravine, however, is not the only one of the kind along 
 the flanks of the Lammermuir Hills. Several of smaller dimensions 
 occur in the same neighbourhood, where small rivulets have worked their 
 way through the red sandstones and conglomerates that flank the 
 Silurian rocks of the chain. Some deep rents are also to be seen along 
 the coast, as at Dulaw, where the streamlet has formed a ravine fully 100 
 feet in depth. On the south-eastern edge of the chain the water-courses 
 are less precipitous ; instead of jagged defiles, they usually occupy the 
 bottom of valleys that are bounded on either side by sloping hills.t 
 
 Of the ground to the north-west of the Lammermuu- chain it is un- 
 necessary to speak here, as only a corner enters the area embraced in the 
 present sheet. It is there, however, that the ravines of the Cockbm-nspath 
 district occur. The south-western, edge of the chain corresponds with 
 the line akeady indicated, which extending from Dunse to the sea at 
 Coldingham, forms a well defined boundary. From the Whiteadder at 
 Prestonhaugh to the valley of the Eye at Eeston, the hills rise rapidly 
 from the plain to a height of between 800 and 900 feet, forming a long 
 smooth-backed ridge, known as Bunkle Edge. Between the Eye Valley, 
 again, and the Coldingham Shore the distinction between hill and plain 
 becomes in a manner lost, and the surface is broken up into an endless 
 series of ridges and of interlacing depressions that rarely desei've the name 
 of valleys. 
 
 The disti'ict which lies to the south-east of the Lammermuir Hills, and 
 occupies the other half of the present Map, may be regarded as a part of 
 the great merse or plain of the Tweed Valley, bounded, however, on 
 the north-east by a band of hilly ground — a sort of spm* from the Lam- 
 mermuirs — which extends along the coast from Coldingham by Lamberton 
 
 * A corruption still used for Cockburnspath, 
 
 t Mr. Milne Home has described some of these ravines in his paper on the Geology 
 of Berwickshire, Trans. Highland Soc. xi. 180. 
 
PHYSICAL FEATUEES, 5 
 
 to within a mile of Berwick, when it sinks down into the plain. This 
 part of the county is in truth a bay from the level plain of the merse, 
 sweeping northward past Dunse tiU it reaches the foot of the hills of 
 Bunkle Edge, whence it deflects towards the east, and, skirting the high 
 ground of Lamberton Moor, joins the main valley again at Berwick. 
 It is traversed by several streams descending chiefly from the hiUs that 
 lie towards the north-west. Of these the most important is the Whit- 
 adder, which, as just mentioned, issues from the Lammermuir chain at 
 Prestonhaugh, and thence runs in an easterly direction until it falls into 
 the Tweed, yearly two miles above Berwick. Its banks exhibit in many 
 places precipitous sections of the strata which occupy the greater part of 
 the Berwickshire plain, and which are also laid open in a series of deep 
 ravines opening upon the Whiteadder in the neighbourhood of the village 
 of Foulden. 
 
 The coast-line along nearly the whole of the district pourtrayed on the 
 present Map is rocky and precipitous. Here and there, as at Cockburns- 
 path, Coldingham, and Eyemouth, there wee sandy bays bounded by gently 
 sloping shores or by blufis of lesser elevation. But by much the lai'ger 
 portion of the sea-margin is a precipitous clifF-line, hardly accessible save 
 by boat. At Tun Law, to the west of St. Abb's Head, it rises to a nearly 
 vertical height of .500 feet, and forms thus, the highest range of headlands 
 on the east side of Scotland. This wild coast is worn by the incessant 
 surge into caves and arches and solitary stacks ; the haunt of multitudes of 
 sea-fowl. The tides run swiftly round the headlands ; hence, even on the 
 calmest summer day, when the surface of the water is scarce roughened 
 by a ripple, the white foam may yet be seen breaking over many a half- 
 sunk skorry, and mantling along the base of the cliffs. The forms of 
 these precipices vary with the changes of geological structure, the most 
 lofty and rugged being these of the convoluted Silurian sti'ata, with their 
 associated masses of igneous rock, while the most fantastic in outline and 
 the richest in colouring are these of the red and mottled carboniferous 
 sandstones. 
 
 The oldest formation shown on this Map is the Lower Silurian. Its 
 area coincides with that of the Lammermuir chain, and with that of the 
 high ground which forms Lamberton Moor extending from near Berwick 
 to Eyemouth. A third, and considerably smaller portion is seen on the 
 shore for about a mile and a half between Coldingham and Eyemouth, 
 whence it extends for rather more than two mUes inland in a south- 
 westerly direction. Next in order of age comes a remarkable series of 
 volcanic conglomerates, ashes, red felspathic sandstones and marls, which 
 from the scanty fossils detected in them are assigned, though with some 
 hesitation, to the horizon of the Lower Old Bed Sandstone. They rest 
 unconformably on the Lower Silurian strata, and are seen at two localities 
 on the coast, at Eyemouth and at Coldingham, in both of which they 
 separate the smallest Silurian patch from the two larger ones. They 
 then unite towards the south-west in a broad belt, which, extending across 
 from Bunkle Edge to the foot of the Lamberton Hills, proceeds in a 
 south-westerly direction until it is abruptly and unconformably overlaid 
 by an irregular band of red sandstones and marls belonging to the Upper 
 division of the Old Bed Sandstone. At Prestonhaugh on the Whitadder 
 this latter baud rests directly on the Silurian grits and shales, whence as 
 it wheels round by Dunse Law, it expands into the great range of con- 
 glomerate hills of Harden, and then into the basin of red sandstones that 
 flank the Lanunermuir chain throughout the I'est of this county. To the 
 east of Dunse this strip of Upper Old Bed Sandstone after widening out 
 between Bunkle Edge and Lamberton Moor to a breadth of two miles, 
 rapidly dies away, and is succeeded by the Lower Carboniferous series. 
 
 A 4 
 
6 GEOLOGT; of eastern BERWICKSHIRE. 
 
 By referring to the Map it will be seen that the boundary line between 
 the upper members of the Old Eed Sandstone and the base of the Car- 
 boniferous group runs from Prestonhaugh on the Whiteadder in an E.S.E. 
 direction, keeping parallel to the course of that stream until near Mor- 
 diagton the Old Ked Sandstone disappears, being overlapped by the 
 Carboniferous strata which rest directly on the Silurian. The strike of 
 the Carboniferous beds, however, continues the same until about a mUe 
 from Berwick, when it takes an abrupt turn to N.N.W., owing to the 
 occurrence here of a large fault. The effect of this dislocation is to 
 throw down the Carboniferous beds against the older formations, and to 
 extend them as a narrow belt between the high grounds at Lamberton 
 and the shore until at Burnmouth the fault reaches the coast-line and the 
 Carboniferous strata, tilted up on end, then run out to sea. On the 
 north-west side of the Lammermuir HUls, another portion of the Old 
 Eed Sandstone is seen resting on the edges of the Silurian grits and 
 slates, and graduating upward, as on the south-east side, into the white 
 sandstones of Dunglass, which there appear to form the base of the Car- 
 boniferous series. Several minor patches of Old Eed Conglomerate 
 occur as outliers in various parts of the district. One of these forms the 
 rounded eminence called the Bell Hill immediately to the south of St. 
 Abb's Head, another occupies the crest of the headland at Eyemouth, 
 known as Cromwell's Fort, a third hangs as a prominent crag on the 
 seaward face of the Chesters Hill at Burnmouth, a fourth of only a few 
 yards in circumference lies near the bottom of the Burnmouth ravine, a 
 fifth is cut open by the railway at Lamberton Shields, and the sixth, and 
 largest of all, occurs on the west side of the great fault between Marshall 
 Meadows and the Steps of Grace. The relative proportions of these 
 outliers are best shown on the Map. No such detached parts of Car- 
 boniferous rocks occur in the district. 
 
 The igneous rocks shown on this Map are for the most part associated 
 with the Silurian strata, and with the ashes and sandstones of Lower 
 Old Eed Sandstone age. One large mass of greenstone, however, occurs 
 in the Upper Old Eed Sandstone, and forms a considerable hill to the 
 west of Dunse, a capping of basalt crowns Dunse Law, while several 
 dykes occur in the same neighbourhood. Five dykes of greenstone were 
 observed on the coast running out to sea in an E.N.E. direction -and 
 cutting through both Carboniferous and Silurian beds. One of them 
 even crosses the large fault, as may be seen along the face of the pre- 
 cipitous cliff as well as in the railway cutting to the north of Lamberton 
 Shields. 
 
 CHAPTEE n. 
 
 Lower Siltjriai^^ Foemation. 
 
 The district embraced in the present Map has a peculiar interest in rela- 
 tion to the history of geological science. It was here, among the contorted 
 Silurian strata which form the wild headlands to the east of Cockburns- 
 path, that Hutton demonstrated the revolutions which the earth's crust 
 hud undergone by showing that grits and shales, originally deposited 
 horizontally on the sea bottom, had come to be convoluted and piled up 
 on end, and that their exposed edges had been thereafter exposed anew to 
 the action of the waves which had heaped upon them a set of gently in- 
 clined conglomerates and sandstones. Here too, amid the same contorted 
 Silurian strata, Sir James Hall made his well-known observations on the 
 
LOWER SILUBIAN FORMATION. 7 
 
 effects of lateral pressure in convoluting large masses of stratified rock.* 
 Nor could the early observers have lighted on a district that more 
 clearly illustrates some of the fundamental principles of geology. The 
 rocks are laid bare in long lines of natural section, both upon the 
 coast-line and among the numerous water-courses of the interior, while 
 later years have added the deep cuttings of the North British Eailway 
 across the Lammennuir chain. 
 
 The Silurian strata of this region, as pointed out so long ago by 
 Hutton and his followers, are in the highest degree convoluted and 
 broken. Yet this disturbance has not in any way destroyed the stratified 
 appearance of the rocks, although it has rendered the task of elucidating 
 their order of succession a difiicult and perhaps even an impossible one. 
 The strata are thrown into rapid flexures, the axes of which run in 
 paraUel lines from N.E. to S.W., or N.N.E. to S.S.W. This feature is 
 characteristic not of this district only, but of the whole Silurian tract of 
 the South of Scotland. So persistent is this line of strike of these 
 vertical and highly incHned beds, that the observer may steer his way 
 over the moors and mountains in a straight north-easterly direction by 
 merely keeping his eye on the exposed edges of the rocks as they crop 
 out in' the water-courses and along the hill-sides. If, however, he crosses 
 the strike at right angles, he is perplexed with the rapid and apparently 
 inexplicable changes in the dip of (the strata. For some way, perhaps, 
 he has traced a set of grits dipping, it may be, at an angle of 70° or 80° 
 to N.W., and he believes that the clue of the order of sequence has at 
 length been obtained. Before long, however, he finds the beds become 
 vertical, and suddenly take a contrary dip towards the south-east, and 
 while he casts about for some character, lithological or otherwise, 
 whereby the stratigraphical succession may be followed out, he is met by 
 an abrupt return of the dip to its former north-westerly direction. 
 Hoping now to regain the lost thread, he follows on, trying at every step 
 to identify bands of grit or shale with those that had previously pre- 
 sented themselves, when again another contortion takes place, the in- 
 clination changes once more, and perchance he abandons in despair any 
 attempt to follow out the succession of the Silurian rocks of the Lam- 
 mermuirs. 
 
 ^ome of these perplexing and seemingly anomalous features receive 
 their explanation in the range of sea-cliff towards the east. In the 
 interior we walk along the denuded edges of the strata ; and many inter- 
 vening parts are there obscured by the drift of the valleys, or by the 
 thick moory vegetation of the hills. But along the coast line, where the 
 waves have cut a vertical section some two or three hundred feet high, 
 and several miles long, the origin of the difficulties that so beset us among 
 the uplands is at once explained. We there see that in ascending the 
 river-courses we had been in reality crossing a series of rocks thrown 
 into rapid arches and troughs, and that the abrupt and puzzling changes 
 of dip really represented the alternating sides of these great folds and 
 curvings of the strata. As the general trend of the coast hne is from 
 N.W. to S.E. it crosses the strike of the beds, and hence the section thus 
 laid bare represents pretty nearly the true relative proportions of the 
 curves, not much distorted, as they would be by any marked deflection 
 from a line transverse at a right angle to the axis of plication. With a 
 sinuous outline, there are of course numerous parts of the coast where the 
 
 * See Hutton's " Theory of the Earth," vol. i. p. 454 et seq. ; Playfair's "Illustra- 
 tions of the Huttonian Theory," p. 213 ; "Life of Hutton," Playfair's works, vol. Iv. 
 p. 78 ; Sir James Hall, " On Vertical and Convoluted Strata," Trans. Roy. Soe 
 Edinb, vii. 79 ; " On the Revolutions of the Earth's Surface," lb. p. 162. 
 
8 GEOLOGY OF EASTERN BEEWICKSHIEE. 
 
 cliff exhibits a more or less oblique section, but the same indented 
 character enables us to correct such distortion, by constantly presenting 
 coves and creeks where the true direction of the beds is shown. 
 
 Yet although the coast rocks explain the causes of those rapid changes 
 of inclination which are often so difficult to follow in the inland parts of 
 the country, they present new obstacles to the determination of the order . 
 of succession among the Silurian strata of this part of Scotland. _ The 
 curvings are not all mere simple folds, but are sometimes so reduplicated 
 upon each other that it becomes next to impossible to decide whether, 
 after we pass beyond such a disturbed belt, we are upon higher or lower 
 beds. And as if to crown the difficulties, the curves are not unfrequently 
 broken through by faults. These cut off abruptly the thread whereby 
 the observer may have been attempting to follow out the order of super- 
 position, and they leave the task well nigh as hopeless as ever. 
 
 The great Silurian tract of the South of Scotland appears to be 
 traversed along its centre by an anticlinal axis which, passing south of the 
 town of Moffat, stretches away towards the German Ocean on the one 
 side of the island and to the Irish Sea on the other.* On the north-west 
 side of this line the strata, notwithstanding their endless crumpUngs and 
 plications, dip on the whole away towards the north-west, so that in 
 passing over the hiUs on that direction, we gradually ascend from a- low 
 part of the Lower Silurian series to the upper parts of that group (as 
 developed, for instance, in the valley of the G-irvan, in Ayrshire) until 
 we reach even the true Ludlow rocks of the Upper Silm'ian series, as 
 shown among the hills of Lesmahagow and in the Pentlands, Again, in 
 traversing the chain towards the opposite quarter we meet Avith the 
 same evidence of a gradual ascending series fl-om the dark slates at the 
 bottom of the system up into the Upper Silurian strata of the south of 
 Kirkcudbright and the hills of Cumberland.f This structure is rendered 
 visible by a gradual change in the lithological character, and still more 
 in the fossil contents of the strata, rather than by any clearly traceable 
 upward succession of bed upon bed. We see that, viewed as a whole, 
 the outer edges of this long Silurian zone are formed of strata higher in 
 geological position than those of its centre. But it is very difficult to 
 decide in any particular district whether one set of beds is actually 
 higher or lower than another. At the best the decision in most cases 
 rests only upon a combination of probabilities. 
 
 The anticlinal axis observable in the central and south-western por- 
 tions of the Silm-ian belt is in aU likelihood prolonged to the north-east ; 
 but I have not yet been able to recognize it with certainty in the Lam- 
 mei'muir district. Prom Du'rington Law across the Lammermuir chain 
 to Gifford the prevailing inclination of the Silurian strata (as shown on 
 Sheet 33 of the Geological Survey) is towards the north-west. These 
 hiUs therefore probably lie on the north-western side of the axial line. 
 If we draw a line from Dirrington Law in a N.N.E. direction to the sea, 
 at a point between Fast Castle and Dulaw Dean, and then examine the 
 Silurian strata to the south-east, we shall find their general dip to be 
 south-easterly as far as the great trough of Lower Old Red sandstones 
 and ashes to be afterwards described. We might therefore infer that the 
 anticlinal axis runs out to sea somewhere to the east of Fast Castle. But 
 when we pass to the eastward of the belt of Lower Old Red Sandstone, 
 and examine the coast section from Eyemouth to Burnmoutli, we find the 
 
 * See Sedgwick, Edinb. New Phil. Journ., xlix. 369, li. 250 ; Nicol. Quart. Journ. 
 Geol. Soc., vi. 53 ; Harkness, op. cit., vii. 46, xii. 238 ; MurcMson, lb. vii. 162 ; 
 Siluria, 3d Edit., 167. 
 
 t See Sedgwick, loc. cit. ; Murchison, Quart. Journ. Geol. Soc, vii. 139, 
 
LOWER SILURIAN FORMATION. 9 
 
 Silurian beds rising again, and dipping rapidly towards the north-west. 
 Hence the line passing by Dirrington Law to near Fast Castle may be 
 merely a minor axis, whUe the great fold lies further to the south-east, 
 near BerwicIs-upon-Tweed. So much of the Silurian ti'act is here 
 obscured by later formations that it wiU probably be safest to delay the 
 attempt to solve this question until the districts lying to the south-west 
 have been surveyed in detaO, and the Moffat axis has been extended 
 further to the north-east. 
 
 So far as can be ascertained at present, the Silurian strata pourti-ayed 
 on the present Map, as well as those on Sheet 33, do not belong to so low 
 a horizon as those along the anticlinal axis at Moffat. They are probably 
 mtermediate between the dark slates of that district and the fossiliferous 
 limestones and grits of Ayrshire, thus coinciding with the second group 
 of Professor Sedgwick.* Such general definitions are perhaps all that 
 can be attempted in the almost complete absence of fossils. My friend, 
 Mr. Stevenson, of Dunse, found a fi'agment of a graptolite in the shales 
 of the Dye Water (Sheet 33), but it was not speciiicafly determined. In 
 similar strata at the Siccar Point, I was fortunate enough, in company 
 with Professor Ramsay and Mr. Salter, to find a well-marked specimen 
 of graptolithus priodon. A few additional specimens were afterwards 
 procured by the Survey Collector, Mr. Richard Gibbs, who, along with 
 myself, detected another band of dark shale containing graptolites in the 
 Headshaw Bmii, at the head of Lauderdale (Sheet 33). Near EUemford 
 (Sheet 33), in p, group of fine shales, I found some well-preserved tracks, 
 apparently of annelids. With these exceptions, however, the Silurian 
 rocks of the Lammermuirs have as yet proved ban-en of organic remains. 
 
 Throughout the whole of the district under review the Silurian rocks 
 pi-esent little diversity of lithological character. They are made up of 
 vai'ieties of grit or sandstone and shale. The grit, or greywacke, as it 
 was foiTnerly called, ranges in texture from a very fine-grained homo- 
 geneous rock, usually of a duU yellowish- or blueish-grey colour, to a hard 
 coarse sandstone, or fine pebbly conglomerate.^ It occurs in bands some- 
 times less than an inch in thickness, but sometimes several feet. These 
 bands are frequently separated by thin ehaly partings. The shale also 
 occurs in bands of several yards in depth, as near Siccar Point, the sti-ata 
 however being thin and hai'd, and easily separable into laminEe. It is of 
 alternations of such compact sandstone and indmvited shale that the great 
 mass of the Lammermuir Hills consists. Not only aire these stiata singu- 
 larly destitute of fossils, but they fail also to present any well-marked and 
 persistent lithological zones by which then- order of succession might be 
 followed. In the course of the Dye Water (Sheet 33) indeed, we meet 
 with certain bands of grit and shale, which can be traced fi'om stream to 
 stream across the hills for a distance of one or two miles ; but these, as 
 they pass under the moors, are speedily lost, and when, after an interval 
 of several miles, we again encounter a water-eoui'se, we fail to recognize 
 them among the vertical or convoluted strata there laid open. No beds 
 of limestone are known to exist in this part of the Silm-ian region ; nor 
 has any thick bed of conglomerate been detected. The sti-ata, in 
 short, consist of endless and rapid alternations of the same materials, so 
 that lithological characters alone are wholly insufficient to guide us to a 
 knowledge of the structure of the chain. 
 
 * Edinb. Phil. Journ. for October 1851. 
 
 f Sir James Hall rejected the " uncouth term " greywaxiki, and adopted that of 
 hillas, a name used in Cornwall to denote a similar kind of rock (Trans. Koy. Soc, 
 Edinb. vii. 79). His substitute never passed into general use. 
 
10 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 Without pretending therefore to have succeeded in determining the 
 true order of succession of the strata in this district, as related to the 
 other Silurian rooks of the South of Scotland, I shall describe their mode 
 of arrangement as revealed in the coast section from Burnmouth, 
 where they are cut off by the Lower Carboniferous group, to near the 
 Siccar Point, where they pass under the Upper Old Red Sandstone. 
 
 By referring to the accompanying protraction of this cliff-sectipn (PL 
 L), the reader will observe that the SUurian sti'ata there exhibited may be 
 regarded as lying in a great trough, and then arching out again towards 
 the north-west. This ti-ough corresponds to the belt of Lower Old Eed 
 Sandstone ash. On both sides of the belt the Silurian strata, though 
 violently crumpled and contorted, may yet be seen rising from imder the 
 unconformable newer formations. Traced towards the north-west they 
 are found to descend again in that direction, when the Upper Old Eed 
 Sandstone covers them up. South-eastward they are replaced by Lower 
 Carboniferous strata before they show any decided tendency to fold over 
 towards that quarter. 
 
 Beginniag then at the south-east corner of the Map, the first Silm-ian 
 rocks met with in Scotland are those that extend from Halidon HUl across 
 Lamberton Moor to Eyemouth. They reach the sea a Httle way north of 
 Burnmouth, and here let us begin their examination. The deep narrow 
 glen descending through the precipitous cliffs above that fishing village 
 has been excavated through highly-convoluted strata of grit and shale, 
 which are here ti-aversed by several dykes of felstone. The great bends 
 and twistings of these rocks are well shown, especially on the north side of 
 the ravine, where a thick felspathic dyke, forming a prominent feature, cuts 
 across a sjmclinal trough 'of the strata, which on the west side are thrown 
 into a vertical position. At the foot of the ravine the shore is observed 
 to be covered with long parallel reefs of rock covered with sea-weed. 
 They run in a N.N.E. and S.S.W. direction, and on examination prove 
 to be vertical, or nearly vertical, beds of sandstone and shale belonging to 
 the Lower Carboniferous series. They ai-e faulted against the older rocks, 
 and will be afterwards described along with the remarkable dislocation to 
 which they owe their present position. Turning northwards along the 
 coast-line, high cliffs rise abruptly on the left, and a tumbled chaos of 
 fallen blocks protrudes from the base of the slope into the sea. Among 
 these ruins, however, not a few craggy rocks exist in place, — fragments 
 of the cliff, which stOl stand up where the surrounding portions have 
 been swept away. The most striking of these isolated rocks and reefs 
 are dykes of felstone, which, running moie or less parallel with the strike 
 of the grits and shales, have been able to resist longer the action of the 
 weather and the waves. These features are best displayed at a pic- 
 turesque part of the coast-line, beyond which it is no longer possible to 
 advance on foot along the base of the cliff. There, some massive fel- 
 spathic dykes, traversing the convoluted strata, have been worn into 
 isolated fragments and sea-stacks — the favourite haunts of numerous 
 gulls and awks. One, called the Breeches Eock, consists of a dyke or 
 bed of felstone, inclined inland at a high angle ; the strata have been 
 worn away from its lower part into a narrow arch, so that the rock, seen 
 from some points, looks like a pair of colossal and not very elegant legs. 
 The Gull Eock stands up, red and rugged, a short distance further north, 
 among dark highly-twisted and broken strata. The accompanying figure 
 represents the position of these dykes, and the contorted aspect of the 
 grits and shales. The dyke to the left hand is the Breeches Eock, its 
 peculiar outline, however, not being well seen from this point of view ; 
 that in the centre is the dyke of which the Gull Eock has been left as 
 an outlying fragment. 
 
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 K I A>a HVHOI 
 
 sniis yuvawvw 
 
 O 
 
 lUOHS 
 
 3Nvaswm 
 
 
 
 INlOd 3A03alilV; 
 
 \- 
 
 \ 
 
 
 
 nj.svo ISVJ 
 
 3tiOHS WDINJT g? 
 
 •r. 3ft03 inoos r 
 
 HOnSHQlU I' 
 
11 
 
12 
 
 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 From the ravine of Burnmouth to these rocks the Silurian beds are 
 inclined towards W.N.W. at high angles, but, as their strike is thus 
 nearly coincident with the direction of this part of the coast-line, and as 
 the cliff is much obscured in places by grass and debris, the details of 
 their structure cannot be fully examined. North from the Grull Rock, 
 however, the cliffs shoot up perpendicularly from the sea in vast walls of 
 naked rock, along the base of which the observer can, in calm weather, 
 make his way by boat, landing here and there in creeks and inlets to 
 complete his observations. 
 
 Immediately west of the Gull Eock dyke, as shown in fig. 1, the 
 strata undergo considerable plication, the arches and troughs being 
 here and there stiU further complicated by small dislocations. The 
 greater amount of irregularity may be due to the causes to which the 
 accompanying dykes owe their origin. For as we advance northward 
 beyond these dykes, the strata, though still violently crumpled, are bent 
 into larger and more regular folds. The Fancove Head exhibits a well- 
 
 Fig.2. 
 Curved Silurian sti'ata at the Fancove Head, 
 
 ■rW'i'^m 
 
 defined trough, and from this headland westward into the little bay known 
 as the Hurker Haven, the magnificent cliff-face contains two anticlinal 
 and two synclinal axes, and a fault by which one side of the eastern anti- 
 cline is abruptly cut off. 
 
 At the Bleak Heugh, immediately to the north of the Hurker Haven, 
 the cliff attains a height of 337 feet above the sea, which is one of the 
 highest pqints of the coast-line on the east of Scotland. The dip of the 
 plications stiU continues W.N.W. at angles varying from 45° to 60°. 
 Here and there a bed of felstone may be seen intruded among the grits 
 and shales, as at the foot of the Bleak Heugh. Dykes of greenstone also 
 traverse the strata, but they usually come up through nearly vertical 
 fissures, and seldom run between the planes of bedding. The best 
 example along this part of the coast-line is furnished by the Scout Cave. 
 A thick dyke of dark augitic greenstone, weathering into spheroidal 
 masses, ascends the face of the steep cHff. Its lower portion, bordering 
 the sea-level, has been worn by the waves into a long dim guU-haunted 
 cavern, in which the tides are ever gurgling to and fro. Some smallef 
 
LOWER SILURIAN FORMATION. 13 
 
 connected veins of the same material may be seen among the strata to the 
 south of the main dyke. 
 
 North of the Scout Cave the dip still continues north-westerly, though 
 the strata are subjected to many minor twists and folds. These bendings 
 increase in number as we advance towards Eyemouth, until in the space 
 of half a mile east from that village they are so abundant that it is im- 
 possible to represent them on the Map ; nay, it becomes no easy task to 
 foUow them out along the cliffs. The beds are bent into endless small 
 anticMnal and synclinal folds ; and even where they do not turn quite 
 over, they are crumpled up and puckered as if they were so many sheets 
 of paper. Nevertheless the general inclination is still towards the north- 
 west, until dipping at an angle of 40°-55° the strata sink below the Bay 
 of Eyemouth, after which they do not re-appear for fuUy more than a 
 mile. The west side of this bay is occupied by masses of ash and con- 
 glomerate belonging to the Old Red Sandstone series. The junction of 
 these rocks with the Silurian series is not visible. But, as the description 
 of the Map proceeds, this junction line will be seen to be probably a 
 fault. (See fig. 7.) 
 
 The ash and other felspathic rocks of Eyemouth continue along the 
 shore as far as Oallercove Point, where the Silurian grits once more 
 occupy the beach. The junction line here is well seen, and is nearly 
 vertical ; the Silurian strata dip towards a mass of felstone, from which 
 they ai-e separated by an intercalated perpendicular vein or bed of 
 conglomerate. The features of this section, however, will be more ap- 
 propriately described along with the felspathic rocks. The grits and 
 shales, in some places vertical where they come close to the felstone, 
 speedily assume a lower angle. Dipping first towards the east-north-cast 
 as if they descended beneath the felstone, they change round to iiorth-cast, 
 north, and north-west, until they reach the ravine which opens upon 
 Linkim Shore. The reefs upon the beach, which is here called Hally- 
 down Shore, permit the observer to trace the full sweep of this curve, 
 especially when looked at from the top of the cliff. They reveal also five 
 or more knobs of a compact pink felstone, which has been intruded 
 among the strata probably, anterior to the eruption of the Callercovc 
 felstone, from which it widely differs. One of these masses is seen in- 
 tersecting the grits and shales immediately to the west of Callercove 
 Point. Another ruhs out to sea beyond the curious sea-stack called 
 Linkim-Kip. In connexion with these dykes and the adjacent larger 
 masses of felstone, it deserves to be noticed that the Silurian strata here 
 have a markedly red colour, and are a good deal hardened, yet they are 
 by no means so crumpled and twisted as in the cliffs between Eyemouth 
 and Burmnouth, affording in this respect a good illustration of the fact, 
 to which further reference will be made ia a subsequent chapter, that 
 the most violent contortions of the strata are not seen in those places 
 where igneous protrusions are most plentiful, but that on the contrary, 
 where such dykes and bosses most abound, there the strata have often 
 been least crumpled. The angle of dip from Callercove Point to Linkim 
 Shore is for some distance as low as 24°, and except near the Callercove fel- 
 stone it does not reach 50°. The detached block of rock called Linkim Kip 
 exhibits a well-marked twist in the red grits and shaJy partings of which 
 it consists. To the west of this headland, the strata, as seen along the 
 high cliff, have a duU red colour, which has probably been superinduced 
 upon them ; they ai'e also much twisted and broken, and have sometimes 
 very much the aspect of burnt brick. So far, indeed, has the process 
 of altemtion b6en cai-ried, that it is extremely difficult to decide whether 
 some parts of the cliff ehould not be regarded as felstone. On the beach, 
 
14 GEOLOGY OF EASTEKN BERWICKSHIRE. 
 
 however, immediately in front of this cliff' the beds are seen dipping 
 north-west at 30°-50°. They are then immediately reversed to the 
 south-east, and arch round again into Coldingham Bay, as they do 
 between Callercove Point and Linkim Shore. There are thus two com- 
 paratively flat anticlinal arches of the Silurian sti-ata visible between 
 Eyemouth and Coldingham. But although these curves are in all 
 likelihood formed by a repetition of the same set of beds, they present 
 some striking differences in colour, texture, and arrangement. That to 
 the south-east, as we have seen, is distinguished by the red tint, and 
 gentle inclination of its grits and shales. But along the north-western 
 curve the beds have a greenish and yellowish hue, and are more broken, 
 gnarled, and altered than in any other part of this district. The red 
 colour in the one case is probably connected with the metamorphic action 
 by which the beds have been altered in texture. The paler tints of green 
 and yellow in the other instance are not greatly different from some of 
 the ordinary colours of the Silurian rocks of the Lammermuirs. It is 
 at the stream which descends upon Linkim Shore that the change begins. 
 If we ascend its ravine, we meet everywhere with proofs of intense 
 alteration and disturbance. The strata are knocked about, twisted, 
 comminuted, burnt and fused, or traversed with intersections of felstone 
 in a manner ti'uly wonderful. On the shore to the north-west of this 
 rivulet, where the reversal of the dip occurs, the beds are first of a 
 reddish colour, which is quickly exchanged for different tints of green. 
 All distinction of stratification is in some places whoUy lost, and we are left 
 in doubt whether we are examining aqueous or igneous rocks. A dyke of 
 light pink quartziferous porphyritic felstone forms here a skerry called 
 Leader Kip, and rises from among the altered strata. This, however, was 
 the only undoubtedly igneous intrusion which I observed between Linkim 
 Shore and the mouth of the Milldown Burn, so that in this instance, 
 as was remarked in that of the HaUydown Shore, the intensity of the 
 metamorphism cannot be shown to depend upon the presence of igneous 
 masses. From the Leader Kip onwards towards the north-west, the 
 yellowish and greenish grits and shaly partings continue to show a high 
 degree of alteration. They are greatly puckered up and gnarled, yet 
 their dip is easily traceable. They are first seen veering round to the 
 east ; their inclination then continues for a furlong or two towards the 
 north-east, after which it bends round more to the north, until at the 
 mouth of the Milldown Burn it is once more north-west. Here 
 the rocks are in some parts slightly calcareous. A curious block of 
 fused Silurian fragments standing On the declivity about the middle of 
 the little bay, and known as the " Deil's Dander," indicates (I was in- 
 formed) where an attempt was once made to bum these calcareous bands 
 for lime. The headland on the north-west side of this bay, which it 
 separates from the Bay of Coldingham, is called Homelie KnoU. It con- 
 sists of the same greenish-yeUow grits and shaly bands in nearly vertical 
 beds, but much crumpled, twisted, and altered, and traversed by two 
 small veins of pink felstone. As we advance into Coldingham Bay, the 
 north-westerly dip becomes more and more decided, until about the 
 middle of the bay the Silurian rocks are replaced by a series of ashes and 
 felstones, similar to those of Eyemouth. 
 
 The shore for about a mile, or, measured at right angles to the strike 
 of the Silurian beds, for about half that distance, is now occupied by 
 different igneous rocks to be described in the following chapter. Passing 
 the little fishing village of Coldingham Shore, the first trace of Silurian 
 rocks which we encounter are two small patches of altered grit, seen on 
 the beach between Craig Robin and the Long CaiT, amid felstones and 
 
LOWER SILURIAN PORMATIOK. 15 
 
 ashes. Immediately to the north-west along the seaward base of Bell 
 Hill and the precipice called Halterem's Loup, hardened grits and shale 
 bands are found dipping in a north-westerly du-ection at 50°. But they 
 are overlaid by a hill of conglomerate, and fi'om this point onwards 
 no Silurian strata are again seen until we have passed St. Abb's 
 Head. 
 
 By examining the various bare knolls and water-courses, however, 
 which intervene between Bell Hill and the sea at the west side of the 
 great headland, we can supply in part the missing parts of the section. 
 The grits and shales, as there exposed, are nearly vertical, inclining 
 sometimes to the north-west, sometimes to the south-east. There appear 
 to be at least one trough' and one arch between Halterem's Loup and 
 Pettico Harbour at the west side of St. Abb's Head. But the soil and 
 debris on the surface only permit a partial examination of the rocks. 
 
 At Pettico Harbour the coast section of the Silurian series re- 
 commences, and continues uninterrupted until the descent of the Upper 
 Old Eed Sandstone, a direct distance of five miles. These strata re- 
 semble those between Eyemouth and Burnmouth. They consist of beds 
 of hard grit with thin shaly partings and thicker bands of shale. They 
 are thrown into numerous large folds, and occasionally show a little minor 
 twisting, but they are singularly free from the puckered appearance so 
 marked to the east of Coldingham. In the five or six miles of sea-cliff, 
 at least seventeen or eighteen complete reversals of the dip may be 
 traced, giving rise to as many arches and troughs ;* but if we include the 
 minor twists (such as that at Fast Castle, engraved on the Map) which 
 are also small anticlinal and synclinal folds, we must far more than 
 double this number. The general disposition of these curves is shown 
 on the section, PI. I. And their position on the ground may be gathered 
 from the arrows inserted on the Map. 
 
 Standing on the western verge of the precipices of St. Abb's Head, 
 the observer sees before him one of the wildest cliff-lines on the east of 
 Scotland. The Silurian strata are there thrown into vast folds, which 
 in oft-changing curves jut out, headland after headland, here worn into 
 dim twilight creeks, there standing up as tangle-covered reefs and 
 skerries, or grey sea-stacks, round which the gull, and the awk, and 
 the Solan goose are wheeling above ; while the surge is ever breaking 
 into foam below. His eye can trace the stratification of the chffs as the 
 sun-light falls on each successive promontory, now on an arch that has 
 been half removed by the ocean ; now on a trough that descends deep 
 into the precipice, until these details are lost in the blue distance, as the 
 coast-line bends away by the rocks of Fast Castle.f 
 
 This range of cliffs is most conveniently examined by boat ; but in 
 order fully to appreciate not only the grandeur of the scene, but the 
 geological structure of the coast-line, the observer ought also to walk 
 along the edge of the precipices. Beginning at the httle bay of Pettico 
 Harbour, which lies on the west side of St. Abb's Head, the first fold is 
 a synclinal trough where the grits on the one side dip at an angle of 47° 
 
 * " I reckoned sixteen distinct tendings in the course of about six miles, each of 
 " the largest size, and reaching from top to bottom of the cliffs, their curvature being 
 " alternately concave and convex upwards." — Hall, Trans. Roy. Soc. Edin., vii. 
 p. 81. 
 
 t I have attempted to give the reader an idea of the forms of these cliffs in the 
 sketch -which is prefixed to the title page of this Memoir. There is a sketch of part 
 of the same coast by Sir Archibald Alison in Siluria, 3d edit., p. 166. 
 
 6802. B 
 
16 GEOLOGY OF EASTERN BERWICKSHIEE. 
 
 to north-west, and on the other at 35° to south-east. Proceeding west- 
 wards, we find the south-easterly inclination continuing as far as the 
 Biters Beach, a distance, measured across the strike of the beds, of 
 1,000 feet. As the angle remains nearly uniform throughout this space, 
 there must be here a section of about 560 feet of strata. After an arch 
 at the Thrummie Carr, the dip returns at the Biters Beach to the south- 
 east, and remains so for about 300 feet.* 
 
 A double fold then occurs, which is well seen on the skerry called 
 Biter's Craig. A small arch, and then a corresponding trough can here 
 be traced within the compass of a few yards, after which the south- 
 easterly dip is resumed, but at high angles. The inclination indeed, 
 increases so much, that as we approach Whitestone Heugh the beds are 
 quite vertical, and even reversed 10° beyond. It is not improbable that 
 in this reversal of dip there may be an actual fold of the strata, for the 
 beds again become vertical at Whitestone Heugh, and then assume once 
 more a south-easterly dip at 60°. A pretty twist is seen on a detached 
 rock at the Little Pits, and also on the cliff above the Muckle Pits, 
 where the cliff sweeps up to a vertical height of 500 feet, the highest 
 headland on the east of Scotland. The south-easterly inclination, 
 however, continues the dominant one, until as we near the Heathery 
 Carr the strata are thrown into a number of rapid folds. Two well- 
 marked arches and two corresponding troughs, irrespective of minor 
 crumplmgs, can be counted in the space of 100 yards. The westmost 
 of these is a remarkably sharp syncline seen on the north-west side of 
 the Heathery Carr. The south-east dip is again resumed until at 
 Pikie's Stell the beds gradually become vertical. In this state they_ are 
 suddenly bent over into a sharp arch, but immediately with as rapid a 
 curve they resume the usual dip at an angle of 43°. Along the cliffs 
 that rise from the Moorburn Beach, and around the promontory of the 
 Maw Carr, as far as the western horn of the Shilments Beach, the dip 
 of the beds remains south-easterly, at angles which range from 43° 
 to 60°. The direct distance is rather more than 2,000 feet, and with 
 the strata at an average angle of 50°, this part of the coast-line must 
 display a section of upwards of 1,200 feet of grits and shales. 
 
 The cliff, immediately before we reach the promontory of the Shil- 
 ments, shows a well-defined fracture, on the west side of which the 
 strata are twisted up into a reversed or north-west dip. The hade of 
 this fault appears to be easterly. It does not interfere, however, 
 with the prevalent south-easterly inclination. This is immediately 
 resumed, and continues past the Barleyhole Rocks, the Naked Man, 
 and the Hollow Craig. The angle varies from 50° to 70°, but west- 
 wards it gradually increases until at the Lumsdane Shore the 
 beds are vertical. The dip is now observed to incline towards the 
 north-west, thbugh still at high angles. It continues in this state 
 for 600 yards, until about 150 yards to the south-east of the con- 
 spicuous promontory of the Brander, it reaches verticalitj% after which 
 it turns once more to the south-east. In this instance again it is pro- 
 bable that the high inclination obscures a complete reversal of the dip 
 forming a great trough. The south-easterly dip continues along the 
 Brander cliffs for a short ^ distance, until at the Brander Cove, in one 
 of the most perfect arches of this coast-line, the beds bend abruptly 
 over to the north-west. 
 
 * It may he necessary to repeat that these measurements are not made along the 
 curving outline of the cliflfs, but at right angles across the strike of the beds. 
 
LOWEE SILURIAN FORMATION. 
 
 17 
 
 Fig. 3. 
 Curved Silurian Strata at Brander Cove. 
 
 This is their inclination on the bold out-jutting rock called the 
 Brander. The angle varies here from 45° to 60°, but before we have 
 proceeded 100 yards the sti-ata are fairly on end. At the foot of the 
 Dulaw they are slightly inclined towards the south-east, but between 
 this point and the Souter, they are seen to bend over into an arch 
 and then to rise again in a perfect syncline, after which the strata 
 continue nearly vertical, but slightly dipping to the south-east. As 
 we pass round the Souter and go westwards, we notice a gradual 
 change of the inclination towards the north-west, the angle still ranging 
 upwards from 70°. This change probably indicates another great fold, 
 the top of which has been denuded. 
 
 On the cliffs immediately to the east of Fast Castle the north-westerly 
 dip is suddenly reversed in a beautiful trough. The folding of the 
 beds here shows, what is often seen elsewhere in these cliffs, that th^ 
 shaly partings between the thicker bands of hard grit, are sometimes 
 reduplicated and crumpled up into minor twists, while the grit bands 
 have only suffered from the larger bend. The north-west side of this 
 trough sweeps up into the cliffs above Fast Castle. The ruin itself 
 stands on a promontory where the beds show the same south-easterly 
 dip. Immediately to the west, however, they arch over to the north- 
 west, and in so doing display a small synclinal furrow running along 
 the centre of the anticline. (See sketch-section of this locality en- 
 graved on the Map). The fold by which the beds are thrown over to 
 the north-we^t, thus consist of two arches, with an intervening trough, 
 
 B 2 
 
18 GEOLOGY OF EASTERN BERWICKSHIEE. 
 
 The north-westerly dip now continues for about 1,000 feet, the only 
 noticeable divergence being a pretty little twist which occurs at the 
 Nick Cove. 
 
 From the skerries called The Books, the coast-line turns round 
 towards the south-west, parallel to the strike of the strata ; hence 
 the structure of the cliffs is not so clearly exposed. We can see, how- 
 ever, that along the upper part of the precipice the north-westerly dip 
 contmues at 60° to 70°, while along the base of the cliffs the inclination 
 is south-easterly also at 70°. The coast here, therefore, must run nearly 
 along a synchnal axis. It soon bends round again, however, and we 
 are once more presented with an oblique section across the ends of the 
 strata. At the Eammel Beach the south-easterly dip is replaced by 
 one in the opposite direction, which lasts for about 700 feet, until we 
 have passed the Middle Craig and the Tod's Loup, when the beds turn 
 up with a reversed inclination, and continue dipping towards the south- 
 east, at angles varying from 53° to 70°. Immediately below the outlier 
 of Old Red Sandstone which overhangs the Windylaw Cove, an anti- 
 clinal axis restores the north-westerly dip at an angle of 80", and from 
 this point the grits and shales may be seen on the beach inclined in the 
 same direction, at angles varying down to 65°, until at a distance of 
 200 yards they are overlaid by the Old Red Sandstone, which now 
 descends to the beach. 
 
 Alternations of red and white sandstone and marl occupy the shore 
 from Redheugh for about a mile westwards to Siccar Point. At that 
 headland a promontoiy of the Silurian rocks protrudes seawards from 
 under the overlying sheets of Old Red Sandstone. The junction of 
 the two formations was long ago described by Hutton and Playfair. 
 The grits and shales (here containing graptolites) on the east side of 
 the Point are first vertical, their edges being capped along the summit 
 of the cliff by red sandstones, which dip away to the north-east. At 
 the northern front of the promontory this inclination brings the sand- 
 stone down to the sea-level.. It is then seen ledge after ledge slipping 
 out to sea, with here and there a knob of the older strata protruding 
 through it. On the west side the vertical position of the Silurian beds 
 changes into an inclination to the south-east at angles varying from 55° 
 to 65°. Proceeding westwards we find this dip to continue with here 
 and there a little confusion, until nearly half a mile west from the Siccar 
 Point, the grits and shales, sometimes vertical and sometimes inclined to 
 the north-west at 50° to 60°, are finally concealed by the red sandstones. 
 From this point northwards, the eastern coast-line of Scotland presents 
 no further exposure of Silurian formations till after crossing the basins 
 of the Forth, the Tay, and the Esk, we reach the Metamorphic Silurian 
 slates and schists of Stonehaven. 
 
 The coast-Kne now described presents so continuous a section of the 
 Silurian rocks of Berwickshire, that it is hardly necessary to give any 
 details of the interior. Indeed, the inland sections are in general so in- 
 terrupted, that they afford comparatively little assistance in interpreting 
 the sti-ucture of the country. By compai'ing the dips inserted on the 
 Map with the section PL I., and the description which has been given 
 of the coast-line, the reader wiU perceive that the range of Silurian 
 hills represented on the present Map as cut off by the s^ between Siccar 
 Point and Burnmouth, may be regarded as composed of a vast synclinal 
 trough, with innumerable minor anticlinal and synclinal axial lines. 
 The middle of this great basin corresponds to the belt of (Lower Old 
 Red Sandstone) volcanic rocks extending from St. Abb's Head and 
 Eyemouth south-westwards in the direction of Dunse and the great 
 Merse of Berwickshire. To the north-west of this belt the prevailing 
 
LOWER SILURIAN FORMATION. 19 
 
 dip is towards the south-east for three miles and a half. In this space, 
 after protracting the angles of dip observed along the cliifs, I find that 
 there are probably not less than 4,000 feet of grits and shales belonging 
 to the Lower Silurian series. The lowest parts of this series appeared 
 to me to occur about midway between Dulaw Burnfoot and Fast Castle. 
 From this point westward the folds are so numerous that there is 
 probably little difference between the horizon of the strata around Fast 
 Castle and that of those at Eedheugh. Arch and trough here succeed 
 each other so rapidly, that a group of beds have no sooner plunged below 
 the sea-level, than a reversal of tlie dip brings them again to the surface. 
 Along the centre of the great syncHnal basin, if we may at least judge 
 from the character of the coast section, the strata are flatter than towards 
 the sides. This was shown in the two flattened arches between Cold- 
 ingham and Eyemouth. Yet it is far from unlikely that this appearance 
 may be exceptional, and due to the disturbing forces which produced 
 the igneous rocks of this part of the district. It is certain that the 
 Silurian rocks here show a more metamorphosed aspect than in any 
 other part of the Lammermuir region ; and this too may be connected 
 with the same volcanic agencies. Unfortunately, there is no means of 
 ascertaining what may be the character of the Silurian rocks along the 
 central trough, as it is prolonged towards the south-west, for before they 
 have reached three miles from the sea, they are covered over by the 
 ashes and conglomerates of the Lower Old Eed Sandstone, nor do they 
 ever again come to the surface throughout the rest of Berwickshire. 
 
 Passing to the south-eastern side of the basin as it rises from the 
 valley of the Eye Water, and sweeps up into the bold headlands of the 
 Bleak Heugh and the moory hills of Lamberton, we find the strata, 
 though often much convoluted, still dipping on the whole towards the 
 north-west. They agree in all lithological features with those to the 
 west of St. Abb's Head. For the sake of assisting the eye to follow 
 the efiect of the curves along the coast-Une on the section, PI. L, I have 
 continued some of the bands of strata by means of dotted lines. It 
 must not be supposed, however, that I have satisfactorily identified the 
 bands marked A, B, and C at aU the points where these letters are 
 marked. As there are here no distinctive features by which any par- 
 ticular zone may be recognized among several thousand feet of similar 
 strata, my identifications are merely approximative, having been derived 
 from a protraction of the observations made during successive ex- 
 aminations of the cliflf-line. 
 
 It is somewhat remarkable, that notwithstanding the great compression 
 which these Silurian strata have imdergone, anything Uke defined cleavage 
 is almost unknown. They are traversed by innumerable joints and frac- 
 tures, but only in one locality have I observed them to be divisible along 
 what may fairly be called planes of cleavage. This occurs at a bend 
 of the Whiteadder, behind the little hamlet of Elba, about a mile to the 
 north-east of Cockburn Law. The grits and shale bands there are 
 fairly on end, and strike towards N.E. by E. They are penetrated 
 by one or two dykes and bosses of a pale felspatliic rock, and also by 
 veins of carbonate of copper, which were once worked here. Between 
 Elba and the Coppermine House in the bed of the river, a group of 
 vertical beds is traversed by a distinct set of cleavage planes, which 
 correspond in strike with the stratification, but cross it at an angle of 
 33° with the horizon, or 57° from the perpendicular of the strata. 
 Some of the grit bands are a good deal jumbled immediately to the east, 
 and the whole aspect of the rocks here suggests very powerful pressure, 
 and no small degree of metamorphism. The metamorphism of the 
 
20 GEOLOGY OF EASTERN BEEWICKSHIEE. 
 
 Silurian rocks, however, will be more properly discussed along with 
 the felspathic rocks, which are so frequent an accompaniment of the 
 altered character of the strata. 
 
 CHAPTER in. 
 
 Lower Old Red Sandstone. 
 
 The vaUey of the Eye Water, from Coveyheugh, near Reston, to 
 where it bends abruptly north-eastward at Ayton, is occupied by a re- 
 markable series of sandstones and fine conglomeratic strata for the most 
 part of a highly felspathic character. The same rocks are exposed on 
 the shore at Eyemouth and at Coldingham Shore ; they are also seen in 
 the Railway, and in various brooks and quarries to the south-west. The 
 occurrence in them of some fragmentary plants and crustaceans appears to 
 indicate that they belong to the Lower Old Red Sandstone. But for these 
 fossils, however, their true stratigraphical relations would be very obscure. 
 Their boundary lines with the Silurian rocks are especially uncertain, 
 except along part of the north-west line of junction, where it can hardly 
 be doubted that they rest upon these rocks with a strong unconformity. 
 The south-eastern junction from the Ale Water to Millertou Hill appears 
 to be a line of fault, while the places on the coast where the two sei'ies of 
 strata approach each other are so obscured by masses of felstone that no 
 safe deduction can be drawn from them as to the order of superposition. 
 
 By reference to the Map it will be seen that a band of Silurian rocks 
 extends from the shore between Eyemouth and Ayton inland for about 
 two miles and a half. This band is then overlapped by the series of 
 felspathic sandstones now under discussion. It fonns in short an axis 
 over which these sandstones are folded. Hence if we pass to the south- 
 west and examine the sections in the Eye Water, we find the sandstones 
 there disposed in an anticlinal arch, those to the south-east dipping in 
 that direction at angles of 35° to 45°, while on the opposite side of the 
 fold the inclination is toward the N.W. at similar angles, until at 
 Reston the strata begin to rise again and slowly dip away from the 
 Lammei-muirs. Between this axial line and the south-eastern boundary 
 of these Lower Old Red Sandstones, the strata do not rise again with a 
 north-westerly dip. They seem in consequence to dip under the Silurian 
 rocks of Prenderguest and Ayton Hill, but this position is explicable by 
 a fault running from Eyemouth by Ayton and Prenderguest, and over- 
 lapped by the Upper Old Red Sandstone of Edingtonhill. 
 
 Such is the structm'e of the area of Lower Old Red Sandstone where 
 crossed by the line of the Eye Water. If however, we try to trace this 
 arrangement towards the sea, we soon discover that as the rocks proceed 
 towards the north-east they change their character to a remarkable 
 degree, losing indeed for long distances all marks of stratification, and 
 that moreover they are confused by dislocations, and by a set of intruded 
 felspathic masses. As a rule we find them coarsest in composition, and 
 most tumultuous in arrangement nearest the sea. From the coast inland 
 they gradually become finer, until at Auclicncraw, where they pass under 
 the Upper Old Red Sandstone, they assume many of the features of 
 ordinary sandstones and shales. 
 
 That these rocks are to a considerable extent the result of volcanic 
 eruptions over the bed of the Lower Old Red Sandstone sea does not 
 admit of doubt. It is particularly observable in such sections as those 
 below the Fort which forms the north-western headland of Eyemouth 
 
LOWER OLD RED SANDSTONE. 21 
 
 Bay. There, both along the cliffs and on the beach, a light purphsh-grey 
 mottled rock — a true volcanic ash — is well exposed'; even on a casual 
 inspection it is seen to consist a mass of angular and sub-angular frag- 
 ments chiefly of various felspathic and porphyritic rocks. Occasionally 
 the eye seems to detect traces of stratification, but these are speedily lost 
 again, and after a short interval others, disposed perhaps in a different 
 direction, take their place. But the rock when viewed as a whole is 
 eminently unstratified. The matrix is felspathic, of a light grey colour, 
 often with brolten crystals of felspar and imperfect tabular crystals of 
 black mica. Of the enclosed stones not a few present a finely-laminated 
 texture, as if they had been fragments of some weU-stratified felspathic 
 ash. The irregular manner in which the stones are imbedded in the 
 general mass, gives it an additional air of confusion, for the well-defined 
 layers of each stone are disposed in a different direction, and at a dif- 
 ferent angle from those of its neighbours. Tracing the rock along the cliff 
 towards its northern extremity, we find the enclosed fragments become 
 fewer in number, and the rock by degrees assumes very much the aspect 
 of a porphyritic felstone, beyond and apparently below which the ash 
 I'e-appears and seems to dip in a north-easterly direction. This felstone, 
 however, is one of the most difficult rocks of the whole district accurately 
 to determine. At some points it contains various felspathic stones, and 
 in such cases i-eally does not differ from the brecciated rock of Eyemouth 
 Bay, with which it might then be classed as a true volcanic ash. But 
 only a few yards off it loses its included fragments, assumes an unmis- 
 takeably porphyritic character, and cannot be described except as a 
 felstone. While mapping its position during the progress of the Survey, 
 I at one time called it an ashy felstone, regarding it as a melted rock 
 which had received in its progress over the sea-bed an accession of stones 
 and smaller lapilli. Again I looked upon it as more probably an ash, 
 that had been showered out as a mass of dust and broken crystals, with 
 fragments of various rocks. Li short it seemed to change its character 
 so often that it is only with extreme hesitation that I have ventured to 
 colour it as a felstone. Its origin, however, is clearly distinct from that 
 of those dark red or brown felstones which have been inti-uded among the 
 Silurian and Lower Old Red Sandstone strata. That it was emptied 
 over the sea-bottom and not thrust among rocks already formed, hardly 
 admits of doubt. 
 
 The upper part of the cliff of Eyemouth Fort is capped by a cake of 
 conglomerate and pebbly sandstone lying unconformably on a denuded 
 surface of the rooks just described. This cake belongs to the Upper Old 
 Red Sandstone series, and will be described in a subsequent chapter. 
 Passing round the headland, with its singularly picturesque creeks and 
 crags, we find on its north-western side, as we approach KiUiedraught 
 Bay, that, as just mentioned, the ash re-appears, rising from under the por- 
 phyritic mass with an E.N.E. dip. Both here and in Eyemouth Bay the 
 two rocks appear to shade into each other. The ash, however, has by no 
 means the same coarse confused arrangement by which it is marked only 
 a quarter of a mile to the south-east. It is much finer in texture, dis- 
 tinctly stratified, and contains two, if not more, beds of a compact red 
 felstone, which are well seen on the east side of KiUiedraught Bay. 
 Below them and nearer the southern angle of the Bay, the ash is finally 
 replaced by a mass of felspathic rocks which occupy nearly half a mile of 
 the shore, as flu' as Callercove Point, and form a range of cliffs 75 to 
 100 feet in height. Here again tliere is the same difficulty of ascertain- 
 ing the origin of rocks that assume the characters both of lava and 
 of ash. The transitions which occm- at Eyemouth Fort arc repeated ; 
 at one moment the rock would be unhesitatingly pronounced an ash, 
 
22 
 
 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 again, after au interval of only a few yards, it might be as confidently 
 regarded as a felstone ; while towards the north-west it presents not a 
 few resemblances to altered Silurian grit. As in the case of the rock at 
 the Eyemouth promontory, I have coloured this range of cliffs as felstone. 
 They do consist ia places of a dark red compact lava-form rock, about 
 the origin of which doubt can hardly be entertained. The greater part 
 of the cliff, however, is formed of a variously tinted porphyritic rock, 
 whUe here and there, as in the south beach of KiUiedraught Bay, there are 
 patches of unquestionable ash. 
 
 At CaUercove Point the felstone is succeeded by Silurian grits, which 
 on the chffs are vertical or highly inchned, but on the shore dip E.N.E. 
 at 33°-55°. The junction, which presents some features of interest, is 
 sketched in Fig. 4. The edge of the felstone is vertical, and even overhangs 
 
 Fig. 4. 
 Junction of Felstone and Silm-ian rocks, west side of CaUercove Point. 
 
 F. Felstone. C, Conglomerate. S. S, Silurian grits and shale. 
 
 a httle to the west. Between it and overlapping the ends of the Silurian 
 beds there is an irreguliar and nearly vertical band of brecciated con- 
 glomerate. The Silurian grits become more twisted as they approach 
 this conglomerate, and their truncated edges can be seen distinctly 
 covered by the latter rock. There must have been considerable disturb- 
 ance here at a time posterior to the production of the igneous masses. 
 When these were erupted the conglomerate may have formed part of 
 a gravelly deposit gathering over the sea-bed and covering the edges of 
 the contorted Silurian strata. The felstone in this way would abruptly 
 close the fonnation of the shingle by rolling over it to form that great 
 sheet which extends along the cliff to KUliedraught Bay. But after 
 these events the old sea-bed has been here upheaved into a vertical 
 position, and even partially overtm-ned, and thus the felstone and con- 
 glomerate, originally more or less horizontal on the inclined Silurian strata, 
 are now placed on end. 
 
 From this part of the coast as far as Coldiugham Bay the only rocks 
 which occur are Silurian grits and shales violently contorted and ti-a- 
 versed by irregular dykes and bosses of various felspathic rocks. We meet 
 with the ash again on the north-west side of Coldingham Bay, whence it 
 extends along the shore as far as Horsecastle Bay, -with the exception of 
 a short interval at the precipice below Bell Hill, called Halterem's Loup, 
 where Silurian sti'ata have been laid bare by the waves. Beginning at 
 Coldingham Bay, we find an ash closely resembling that of Eyemouth 
 Fort. It is in places quite as coarse and unstratified as in the latter 
 locality, and the composition both of the mati-ix and of the included 
 angular stones is equally felspathic. It is wholly impossible along this 
 part of the coast-line to determine in what direction the ash may dip or 
 
LOWER OLD BED SANDSTONE. 2S 
 
 at what general angle it may be inclined. For not only is the rock itself 
 eminently unstratifled, but it is traversed along nearly the whole of the 
 shore by irregular intrusions of a dark red porphyritic felstone, which runs 
 in and out along the beach, sometimes crossing inland, and forming pre- 
 cipitous banks, sometimes stopping abruptly in a tall stack before reach- 
 ing high-water mark, and sometimes running out to sea in a series of 
 rugged reefs and skerries. Those featm-es are well shown as we 
 approach the fishing village of Coldingham Shore. From the picturesque 
 headland of the Castle Rock, the dark felstone runs along the steep bank 
 on which the southern part of the village stands, until opposite the 
 Harbour it makes an abrupt turn to the east, descends to the beach so as 
 to allow the ashy rocks to be once more visible, and then at the mouth of 
 the Harbour, wheels sharply round to the north-west, frmging the beach 
 a Utile above low-water mark, and forming the rocky islets or carrs until 
 in the little bay beyond the Black Craighead it suddenly disappears, and 
 the ash alone occupies the shore. Along this part of the coast there is 
 the same difficulty as at Eyemouth of determining whether certain 
 portions of these igneous masses are to be regarded as truly melted 
 rocks or as the result of ashy ejections. They are in places strongly 
 porphyritic, but again after a short interval they are seen to contain large 
 angular stones different in texture from the general matrix. After 
 visiting the coast several times, I believe that the balance of evidence is 
 in favour of these rocks having been produced chiefly if not entirely from 
 showers of dust and stones. The dark red felstone, however, is un- 
 doubtedly a melted rock, but belongs, I have little doubt, to a much later 
 period than that of the ash. It may be classed with the similar felstones 
 which traverse many parts of the Silurian region, and to which reference 
 will be made on a subsequent page. There is a still later igneous rock 
 on this part of the coast, in the form of a greenstone dyke, which runs 
 N.N.E. through the felstone of the harbour at Coldingham Shore. This 
 dyke is probably contemporaneous with others of a similar character 
 seen near Burnmouth, which fall to be described in Chapter VII. 
 
 The coast becomes still wilder and more precipitous as we advance 
 northwards. The ashy rocks continue visible at intervals among the 
 protrusions of felstone, until at Craig Robin they disappear. Beyond 
 this great mass of felstone, in the bay of which the precipice of Hal- 
 terem's Loup forms the north-west margin, Silurian strata are exposed, 
 dipping N.N.W. under the cliff at 50°. It would appear that these beds 
 have been exposed by the action of the sea in removing the ash which 
 once covered them. They are only visible as far as the Loup, whore 
 they pass below the mass of felstone forming the strange castellated ^xq- 
 montory of the White Heugh. Here too the ashy rocks re-appear, but 
 not in the coarse unstratifled forai which marks their occmxence to the 
 south-east. They are well bedded, dipping eastward at a high angle 
 down the guUy called Rutherford's Brae, where the White Heugh felstone 
 cuts them off towards the sea. Unconformably upon their edges rests a 
 cake of coarse reddish conglomerate, fonning Bell Hill. This outlier is 
 probably of the same age as those near Eyemouth, Bui'nmouth, and Lam- 
 berton — that is, fragments of the Upper Old Red Sandstone, which 
 appears once to have covered the whole of the seaward end of the 
 Lammermuirs and the eastern part of Berwickshire. 
 
 From White Heugh the felstone extends north-eastward in a chain of 
 rocky islets and skerries, leaving the ashy rocks exposed on the beach 
 and along the cliffs. Opposite the reef of the Big Black Carrs, however, 
 it turns landward again as a broad irregular dyke, which is well seen at 
 low water, but does not go further inland than the base of the cliff. 
 Another mass, with minor off-shoots, forms the rugged crags of the 
 
24 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 Horse Castle, and thence runs westward as a line of singularly worn and 
 caverned cliff as far as the head of Horsecastle Bay. Among these 
 intrusive bosses of felstone, the ash is seen at many parts of the coast- 
 line, sometimes in a hard compact form, as if its components had been 
 partially fused together. At Horsecastle Bay there is an instructive series 
 of sections showing the structure and composition of the ash, and the 
 manner in which that rock is traversed by the felstones. The ash is well 
 stratified, its beds dipping seaward at about 20°. Some layers are a 
 kind of coarse breccia of various felspathic stones, which are often 
 beautifully porphyritic. Indeed many parts of this brecciated ash would 
 take a fine polish, and, if obtainable in large enough blocks, would form 
 an excellent ornamental stone. Other beds are much finer in textui'e, 
 consisting of little else than an aggregation of small angular felspathic 
 lapilli. At Horsecastle Bay the ash finally disappears. From this point 
 onwards, for about a mile, the coast is occupied by a huge boss of red fel- 
 stone, which forms the promontory of St. Abb's Head, and descends in a 
 series of the wildest precipices into the restless sea. 
 
 Turning inland now in a south-westerly direction, we find the same 
 ashy deposits exhibited in some of the water-courses, as well as in several 
 artificial openings. The first stream which assists us is the Ale Water, 
 running in a south-easterly direction from the moors of Coldingham, and 
 joining the Eye between Ay ton and Eyemouth. A reference to the Map 
 will show that this rivulet crosses at a right angle the band of Lower 
 Old Red Sandstone, and also the southern edge of that tongue of Silm-ian 
 grits which extends inland from the sea. Ascending the Ale, we first 
 pass over a set of highly inclined and contorted Silurian strata. These 
 are bounded on the west by the fault already described, along which 
 there runs here a dyke of greenstone. From this point the water- 
 course is occupied for more than a mile by a confused grouping of 
 felstone bosses among the ashy rocks. The latter can be studied with 
 advantage in the ravine called Little Dean, on the south side of the Ale, 
 rather more than half a mile above the turnpike-road to Eyemouth, where 
 a tiny runnel has here worked out a steep dell in a coarse felspathic con- 
 glomerate. This rock is made up of well-rounded fragments of various 
 felstones of all sizes, up to two or three feet in diameter, imbedded in a 
 felspathic paste. The rounded character of its pebbles distinguishes the 
 rock here from that at Eyemouth, two miles distant, but it is still unstra- 
 tified, unless some obscure lines represent planes of bedding, inclined at a 
 high angle. In the bed of the Ale, above the Little Dean, there is a 
 confused intermingling of felstone and ash, as on the shore. The alter- 
 ation which has here been effected on the ash has sometimes almost 
 effaced the fragmentary stones of which that rock is composed. They 
 are in places, as it were, fused together, and it then becomes no easy 
 matter to distinguish the ash from some of the surrounding felstones. In 
 other parts of the water-course, particularly at the waterfall near the 
 Linthill Tile-works, the ashy rocks seem intermingled in a perplexing 
 manner with bands of hard grey grit, like the grits of the Silurian series. 
 When I first ascended this stream, before having seen tlie coast sections, 
 and those of the Eye Water and the Railway, the grouping of the whole 
 series of rocks seemed at the time to be involved in utter confusion, 
 though, before quitting the stream, I inclined to the supposition that pos- 
 sibly the ashy-like masses, so knocked about by dykes and bosses of 
 felstone, might form part of the Silurian sei-ies. Nor indeed until the 
 whole district had been examined was I able to satisfy myself that the 
 beds in queslion belonged to a later formation. 
 
 From Alemill Bridge up to Whitfield the bed of the Ale Water is 
 occupied by Silurian grits and shales, occasionally highly altered and 
 
LOWER OLD RED SANDSTONE. 25 
 
 penetrated by felspathic intrusions. One outlying patch of the ashy 
 conglomerate occurs inunediately below Alemill Bridge. A fault appears 
 to separate these rocks from the continuation of the ashy deposits that 
 run inland from Coldingham, and here cross the course of the Ale. 
 This ashy series of rocks is well exposed in the channel of the stream 
 for half a mile, reaching nearly as far as Alewater Bridge. Instead of a 
 confused mass of coarse breccifoim ash, however, we meet with a set of 
 well-bedded felspathic grits and red sandstones, usually more or less ashy 
 in composition and texture. That these strata are really a prolongation 
 of the rocks at Coldingham Shore cannot be doubted, and they thus 
 illustrate a featm'e, already alluded to, that the ash becomes finer in grain 
 and more mixed up with ordinary sediment, as we ti-ace it towards the 
 south-west. Hence it seems reasonable to infer that the focus of eruption 
 lay somewhere towards the north-east. Where these strata are first seen, 
 after passing over the Silurian rocks in the Ale Water, they dip nearly 
 due east at 45°. Three hundred yards higher up the stream they are 
 inclined to the south-west, at an angle of from 15° to 20°. In some places 
 they consist of true led sandstones, soft and crumbling, and with ^vell- 
 marked stratification. This character is peculiarly well shown at the 
 point where the south-westerly dip is first observed. But the general 
 aspect of these strata is usually such as to indicate a derivation from 
 volcanic material. The abundance of small angular variously tinted 
 fragments, which along with their matrix are eminently felspathic, points 
 to the former proximity of some vent, from which dust and lapilli were 
 thrown over the adjacent sea-bed. No fossils were detected here, though 
 some of the beds seem far from unlikely places in which to find them. 
 
 Continuing again in a south-westerly direction, that is, further away 
 from the old volcanic orifice, we notice the ashy strata becoming still 
 finer in texture. They may be seen here and there on the ridge that 
 separates the Ale from the valley of the Eye, but the best section is that 
 exposed in the course of the latter stream, extending over a distance of 
 four or five miles from Coveyheugh to near Ayton. The anticlinal fold, 
 above alluded to, can be readily seen in this section ; its centre being at 
 East Eeston Mill. Fi-om this point, in a south-easterly direction, the 
 strata dip down the stream, at least as far as Aytonlaw, at angles varying 
 from 35° to as much as 57°. Between Aytonlaw and the Silurian tract, 
 to the south-east, they flatten out, but not for a sufiicient distance to allow 
 all the strata to come again to the surface. I have hence inferred that 
 a considerable part of the series is cut off by a fault which, running 
 south-south-west from Eyemouth, separates these deposits from the 
 underlying Silurian rocks. Above East Reston Mill the section is much 
 less consecutive, owing to the low banks and the depth of drift and 
 soil. Where the strata can be seen, however, they dip in a W.S.W. 
 direction as far up as Reston Mill, where they begin to undulate towards 
 the E.N.E. Beyond this latter jjoint the stream aflfords no further in- 
 foi-mation, and the section has therefore to be supplied from the railway 
 cuttings, which lie immediately to the south. There we find the ashy 
 beds dipping gently in a south-easterly direction away from the SUurian 
 hills on which they repose. But the actual line of junction is obscured 
 by masses of felstone, which here, as on the shore, have invaded both the 
 Lower Old Red Sandstone and the Silurian series. With the exception, 
 however, of such interruptions, the two Mnes of section shown iu the 
 Eye Water and the railway dove-tail into each other, and afibrd us as 
 complete a table of the Lower Old Red Sandstone of this disti-ict as can 
 be hoped for. 
 
 Begitming at Ihe base of the series, or at least at the beds which 
 appear immediately to overlie the Silurian grits, we find in the railway 
 
26 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 cutting west of Reston a series of sandstones and conglomerates of a dull 
 red colour, and strongly felspathic. Occasional partings of red marl also 
 occm-, and the whole series undulates gently towards the east or south- 
 east. The conglomerate bands are made up of an aggregate of rounded 
 felstone fragments in a felspathic paste. But the igneous intrusions just 
 referred to, along with some accompanying faulting and fractures, inter- 
 fere with the continuity of the series. From this point onwards, in an 
 easterly direction, we slowly pass over an ascending section as far as the 
 little hamlet of Braehead. Here the railway ceases to afford any indi- 
 cation of the underlying rock, and the channel of the Eye Water is 
 equally obscured. It is not until after the interval of a mile that we 
 meet with strata in place by the side of the Eye, where the stream has 
 cut a shelving bank between Heugh-head Smithy and Reston Mill. There 
 some bands of sandstone occur dipping in a north-easterly direction at an 
 angle of about 12°. They are partly soft, red, and pebbly, partly of 
 a grey micaceous texture, and in one place they contain an exceedingly 
 hard, almost jaspideous band. What is chiefly of interest, however, in 
 these beds is their well-stratified and fine-grained character, so different 
 from that of the ashy rocks on the shore, and beaidng out, as it does, the 
 remark already made, that the strata become coarser and more confused 
 in their arrangement as they pass towards the north-east. 
 
 From Heugh-head Smithy, eastwards, it would apjDear that the rocks 
 rise again to the surface in a synclinal trough, so that in advancing down 
 the stream we traverse a descending section until we reach East Reston 
 Mill, which has been described as the central point of an anticlinal axis. 
 Proceeding along the east side of the arch, we obtain a much more con- 
 tinuous section than that to the west. First, a little above East Reston 
 Mill, some green and pinkish coloured grits occur on the side of the 
 stream. They are, in some of their bands, very ashy in composition, and 
 contain occasional green shaly beds, in which I detected a few imperfect 
 plants. A dyke of dai'k red greenstone traverses them, seen both on 
 the bank and in the bed of the stream. East from the mill, ashy sand- 
 stone crops out along the margin of the water-course, dipping E.S.E. 
 at 37°. Some of the bands are, in truth, merely well-stratified ash, con- 
 taining no admixture of ordinary sedimentary matter ; others do not 
 differ from the common red sandstones of the district. Similar sti-ata, 
 with a like south-easterly inclination and high angle, occur at intervals 
 along the course of the Eye towards Ayton. They are well exposed in 
 the line of rocky bank in which tiie Harry Craig Quarry has been opened. 
 Beds of hard compact felspathic ash, full of angular variously-coloured 
 lapilli, alternate with bands of fu'm red sandstone and marl of the usual 
 character. For the most part the ash is greatly in excess, but there are 
 places where the sandstone and marl occupy a half, if not more, of the 
 general mass. The alterations are so rapid, however, that it is quite 
 impossible, even on maps of so large a scale as six inches to the mile, to 
 separate the ash from the sandstone. From Harry Craig Quarry the 
 strata are visible occasionally down the course of the stream, and also 
 along the parallel section in the railway. They are here not quite so 
 ashy-like in appearance, but resemble ordinary red sandstones and fine 
 conglomerates, though still with a considerable admixture of felsj)athic 
 matter. Their dip in the Eye Water, at the ford below Aytonlaw Cottages, 
 is towards N.N.E. at 20° or 22° ; in the railway it is east and east by 
 south at the same angle. It will be seen that from the perturbed ai-ea 
 above Reston, onwards in a south-easterly direction, the strata, now under 
 description arc remarkably free from those felspathic intrusions which 
 tend so niuch to obscure the structure of the districts in which they occm'. 
 One small boss of felstone occurs among the conglomerates at the ford 
 
LOWER OLD RED SANDSTONE. 27 
 
 just mentioned, and others of similar insignificance may have escaped 
 notice. No sooner, however, do we pass across the line of dislocation 
 which here probably bounds the eastern margin of the Lower Old Eed 
 Sandstone series, than we find ourselves among a set of highly contorted 
 and broken Silurian grits, with many protrusions of felstone. 
 
 Taking now another traverse still further to the S.W., we encounter 
 the same increase of ordinary fine sedimentary matter in the strata as 
 they recede from the coast. The conglomerates and sandstones of Covey- 
 heugh, in the Eye Water and railway, are prolonged on the flanks of the 
 Silurian hills, in a narrow tongue, the southern edge of which is over- 
 lapped uncomformably by the Upper Old Eed Sandstones. This part of 
 the district, however, is considerably obscured, partly by drift lying thick 
 along the lee of the hills, and partly by a number of intrusions of fel- 
 stone, which is often for some distance the only rock visible. If, passing 
 from this conglomeratic zone, we skirt the margin of the Upper Old Red 
 Sandstone tract, we shall find that in the bed of the rivulet due east of 
 Auchencraw Mains, some of the finer portions of the Lower Old Red 
 Sandstone ashy series are exposed, dipping S.E. at from 45° to 50°. They 
 consist in the under beds of hard grey felspathic grits, interbanded with 
 green shales, which I found to be fuU of vegetable remains, and where, also, 
 in company with Mr. Gibbs, the Survey fossil-coUector, I obtained a 
 fragment of the large crustacean, knovra as pterygotus. Some of these 
 strata are still very ashy in appearance, but the lapilli are small, and the 
 matrix contains a good deal of sand and clay mingled with the felspathic 
 matter. The highest beds seen here consist of fissile grey sandstones and 
 red sandy grits with bands of marl, the whole being still more or less 
 felspathic. The uuconfoi-mity of the Upper Old Eed Sandstones and 
 marls upon these older ashy deposits is well shown at this locality. The 
 strata just described in Auchencraw Burn dip at a high angle towards 
 the south-east, but no sooner do we pass into the area of the upper sand- 
 stones than we find the dip change round to south and even S.S.W., while 
 the angle lessens to such a degree that in many places the beds may be 
 regarded as almost horizontal. This change was seen in the railway 
 cutting at Auchencraw Mains, where some soft sandstones and marls of a 
 brick-red colour, like those of the upper series, were exposed in a nearly 
 horizontal position. Only a few yards towards the north-east, however, 
 the hard ashy sandstones and shales may be seen in the brook dipping with 
 a high inclination and at right angles to the beds in the railway, from 
 which also they differ altogether in lithological characters. From Auchen- 
 craw eastward, across the low watershed of this part of the district, 
 stretches an alluvial peat-covered vaUey, known as Billy Mire. Two 
 small rivulets di-ain it in opposite directions, one flowing westward and 
 joining the Whiteadder at Chirnside Mill, the other finding its way 
 towards the east, until it falls into the Eye Water near Ayton. This 
 tract affords, of course, no insight into the nature of the underlying 
 rocks, nor until we cross to its eastern margin and reach the foot of 
 Millerton Hill do we again catch a gUmpse of the ashy series. This hill 
 consists entirely of a fine felspathic ash, with bands of red sandstone, 
 marl and felspathic conglomerate. These strata may be seen in fragments 
 over its whole extent, but are best exposed in a line of low bank that runs 
 south from the railway on the west side of the hill. Their dip varies a 
 few degrees north and south of east, at angles of from 17° to 25°. I did 
 not succeed in detecting any fossils in them, but it appeared a not unpro- 
 mising locality for such a search. On the summit of the hill fragments 
 of the underlying rock are especially abundant. They may be traced all 
 down the east side, nearly as far as the line of the turnpike-road, to the 
 east of which Silurian fragments begin to appeal-. The line of demarca- 
 
28 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 tion between the two foi-mations, in all likelihood a line of fault, must 
 therefore nearly correspond with that part of the high road which runs 
 in a north-easterly direction between Millerton HiU and Whiterig. 
 
 No further trace of the felspathic strata is seen towards the south-west, 
 as they are immediately overlaid by the Upper Old Eed Sandstones of 
 Billy and Edington Hill. Putting together the points in their structure 
 and disposition which have been enumerated in this chapter, we find that 
 a group of rocks occurs in this county presenting throughout the whole 
 of its extent indications of a volcanic origin ; that towards the north-east 
 these rocks become coarse and unstratifiod, passing into true volcanic ash 
 and conglomerate, and having beds of felstone associated with them ; 
 that in a south-westerly direction they lose this tumultuous unassorted 
 ajjpearance, become intermingled with ordinary sedimentary deposits, and 
 contain here and there fragments of plants and crustaceans. We see, 
 moreover, that they rest on the edges of the Silurian rocks, and are 
 covered unconformably by the Upper Old Eed Sandstone, and that they 
 must, therefore, be intermediate in age between these two series ; a con- 
 clusion confirmed by the character of the crustacean remains which 
 indicate the horizon of the Lower Old Red Sandstone. As this part of 
 the formation has not hitherto been recognized in Scotland to the south 
 of the Silurian hills, some interesting questions are opened up as to whether 
 certain districts of the South of Scotland may not belong to the same 
 group. The occurrence of true volcanic rocks of that age is also a fact 
 of special importance, for it may eventually help in the elucidation of the 
 age of the Cheviot and other hills, which are certainly older than the 
 Upper Old Red Sandstone. But these are subjects for future inves- 
 tigation. 
 
 CHAPTER IV. 
 
 Inteusite Rocks in Lowek Silurian and Lower Old Red 
 
 Sandstone Series. 
 
 In the preceding pages reference has frequently been made to certain 
 dykes and irregular masses of various kinds of felspathic rocks, by which 
 both the Silurian and the Lower Old Red Sandstone tracts are invaded. 
 These rocks, occurring so abundantly in many parts of the district, 
 present some features which could not well be described imder the 
 previous formations, and which may therefore fitly form the subject of a 
 separate chapter. 
 
 To begin with those of the Silurian series. A glance at the Map will 
 show the relative size and disposition of the larger felstone intrusions ; 
 but it is impossible, on so small a scale, accurately to define the nume- 
 rous points and veins of felstone whereby the grits and shales are 
 occasionally intersected as in a kind of coarse network. Some idea 
 of the great number of these minor protrusions may be obtained by an 
 examination of the railway sections from Burnmouth towards Lam- 
 berton, and also by a walk along the shore north fi-om Burnmouth in 
 the direction of the Gull Rock already described. One of the first facts 
 which strikes the observer in the course of his explorations among 
 these rocks is their sporadic arrangement. He seldom encounters a 
 solitary dyke or mass. When he meets with one dyke in a stream, he 
 almost invariably finds it but the prelude to a group of greater or. less 
 extent. Thus there is the cluster of veins and bosses round Burnmouth, 
 another to the south-east of Eyemouth, a third in the Ale Water south 
 of Coldingham, a fourth towards St. Abb's Head, a fifth round Cock- 
 
INTRUSIVE ROCKS. 
 
 29 
 
 burn Law, and so on. The same arrangement occurs throughout the 
 Lammermuirs, as shown on Sheet No. 33 of the Geological Survey. 
 Between the groups a considerable interval sometimes occurs without 
 any trace of felstone. Thus the triangular district occupying the 
 north-west half of the present Map between Cockburnspath, Cockburn 
 Law, and St. Abb's Head, appears singularly free from felspathic rocks. 
 The small Silurian tract between Coldingham and Eyemouth is com- 
 paratively free from them along the shore, but contains a considerable 
 number a short way inland. Again, in the area of Silurian strata 
 stretching from Eyemouth to neai- Berwick, felstone protrusions abound 
 in several places, and occur more or less in the whole. 
 
 Cockburn Law and Stoneshiel Hill form parts of one felspathic mass, 
 separated by a deep ravine in which the Whiteadder flows.* The former 
 eminence lies in Sheet 33, but Stoneshiel Hill, along with the valley of 
 the Whiteadder, is displayed on the present Map. These hills are fonned 
 of one of those remarkable granitoid rocks which occur in many parts 
 of the Silurian tract of the South of Scotland. It is in places a true 
 fine-grained granite, composed of smaU crystals of quartz, felspar, and 
 mica. The last mineral is occasionally replaced by hornblende, forming 
 a syenite. Again, both the mica and hornblende disappear, and the 
 rock becomes a quartziferous porphyry, and then, on the cessation of 
 the quartz, we have a felstone of the ordinary type. Such interchanges 
 are rapid, and may be traced in succession on the same hiU-side. Thus 
 the Whiteadder at the farm of Cockburn flows over a crystalline granite. 
 If, however, we ascend Stoneshiel HiU in an easterly direction, we find 
 first the mica and hornblende disappear, then the quartz, until at the 
 east end of the hill we meet with a felspathic rock like the ordinary 
 felstones of the district. The same change is still better seen by pro- 
 ceeding westward along the higher parts of Cockburn Law. If, on the 
 other hand, instead of ascending the hiUs on either side, we continue 
 up the channel of the river, the granite will be found to become finer in 
 grain, and to show an increasing resemblance to some of the more altered 
 Silurian grits, until, at last, the true Silurian grits are reached. This 
 apparent gradation of these so-called igneous rocks into ordinary sedi- 
 mentary strata will be immediately alluded to. 
 
 Round the outskirts of this great granitic mass a number of minor 
 veins and irregular dykes occur. Below Cockburn Farm two such veins 
 may be seen among the highly-altered grits and shales ; one consisting 
 of felspar and quartz with specks of brown mica ; the other, an ordinary 
 pinkish porphyritic felstone. A small knob of granite occurs between 
 the farm-house and the Law, and a still more insignificant felspathic vein 
 intersects the grits in the quarry to the south. Again, to the north of 
 the main mass, many smaller protrusions may be seen in the bed of the 
 Whiteadder and its tributaries. For instance, at the abrupt bend of 
 the stream, before it reaches the " Devil's Dungeon," two parallel bands ■ 
 of felstone may be seen conforming to the dip and strike of the strata 
 among which they have been introduced. The angle of inclination of 
 the whole series is from 45° to 55° towards W.N.W. The upper fel- 
 stone is a compact, homstone-like rock, of a pinkish colour, save where 
 an abundance of serpentine communicates a greenish hue. Along the 
 junction of its upper siu:face with the overlying Silurian beds, the two 
 rocks are, as it were, fused together, the grits containing crystals of 
 
 * See an excellent description of the locality by my esteemed friend, Mr. Stevenson, 
 Dunse, in the 16th vol. of the Transactions of the Royal Society of Edinburgh, p. 33. 
 
30 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 hornblende aud iron pyrites. At the under part of the vein the shales 
 have been converted into a kind of Lydian stone. The second felstone 
 dips at an angle of 52°; it is dull, granular, and porphyritic, and resembles 
 the first in colour aud in the amount of alteration which the strata in 
 its neighbom-hood have undergone. Still further northward, some in- 
 teresting sections of the relation of the felspathic veins to the Silurian 
 strata are laid bare at the old copper mines. The grits and shales are 
 there vertical, and in some parts considerably squeezed and broken, and 
 several veins and knobs of pinkish felstone traverse them in a direction 
 more or less parallel with their strike. Of these there is one which 
 stands up in a small crag in the channel of the Whiteadder, immediately 
 below the end of the garden of the Coppennine House. It is a dull grey 
 serpentinous rock, with small granules of transparent quartz and carbonate 
 of lime. The cleavage of the strata here has been already referred to. 
 
 In the line of section laid open by the Ale Water through Silm'ian 
 rocks between Whitfield and Alemill Bridge, several points of interest 
 occur. Below Whitfield there are some intrusions of dull earthy fel- 
 stone, occasionally of a yellow colour, like the grit among which they 
 lie. Further down the stream, by the side of Whitfield Plantation, 
 there are at least two patches of felstone, hard, compact, and almost 
 flinty, graduating insensibly into the neighbouring grits and shales, 
 which are, of course, greatly altered. Below Alemill Bridge a similar- 
 hard flinty felstone occurs, which it is difficult to distinguish from 
 some of the more metamorphosed grits, except that it shows no trace 
 of bedding. 
 
 The dykes of felstone which traverse the Silurian strata along the shore 
 between Fancove Head and Burnmouth nearly coincide with the general 
 strike, though they continue in an imeven wriggling com-se, and some- 
 times even send out minor veins that cross the strata at right angles to 
 the strike. The coincidence of direction, however, between the dykes 
 and the stratified rocks is never such as to leave the observer in any 
 doubt as to the really intrusive and subsequent origin of the former. 
 They cannot be mistaken for contemporaneous lava-flows erupted during 
 the deposition of the Silurian series. 
 
 Along the railway cuttings at Burnmouth occur the best sections in the 
 whole district for the display of dykes and contorted strata. From the 
 beginning of the cuttings near Fairneyside to a point a little beyond 
 Greystonelees, which is a space of exactly a mUe, I counted 23 separate 
 veins and dykes of various felstones intersecting the contorted grits and 
 shales. Over the greater part of this space the rocks cannot be traced 
 to the sea owing to the large fault which here runs parallel to the coast- 
 line, and brings down a low zone of the carboniferous series, but Ln the 
 glen of Burnmouth the felstones may be seen descending from the railway, 
 crossing the ravine, and then running along the cliff above the fishing 
 •hamlet of Partanhall. It will be seen that here too the strike of these 
 veins coincides on the whole with that of the strata which they traverse, 
 though when examined in detail they ai-e found to break through the 
 grits and shales in the most irregular way. Nothing can well be more 
 broken and confused than the groupmg of these strata along the line of 
 the railway. Their dip is chiefly to N.W., at various angles, from not 
 more than 10° or 20° up to verticality ; but this inclination is often 
 reversed, and the beds are thrown into a series of rapid pUcations. These 
 changes are increased by the numerous veins and dykes of felstone, along 
 the side of which the dip is sometimes suddenly altered. The subjomed 
 figure represents a portion of the grits and shales squeezed up between 
 two dykes of porphyritic felstone in the railway cutting immediately to 
 the east of the Burmnouth Station. 
 
INTRUSIVE ROCKS. 31 
 
 Fig. 5. 
 
 Contorted Silurian strata between two Dykes of Felstone. Eailway 
 Cutting, Bummoutli. 
 
 In lithological character these felstones do not differ from those aheady 
 described. They are sometimes compact, fine-grained, of a pale pink or 
 yellowish colour, with occasional granules of transparent quartz, crystals 
 of felspar being in such cases not unfrequent. In other places they are 
 of a dark reddish-brown colour, more or less earthy in texture, and 
 highly porphjTitic, or they assume a fii-m granular or finely crystalline 
 texture, and a light grey hue, and then they present a close resemblance 
 to some of the more altered bands of grit. The amount of metamorphism 
 traceable in the strata here is not on the whole great. Some of the 
 shale bands occasionally assume somewhat the aspect of Lydian stone, 
 but they are smashed and crumpled rather than actually metamorphosed. 
 
 The felstone of Lamberton Moor occupies a considerable area, and is 
 one of the most beautiful rocks of the district, beiag highly porphyritic, 
 and of a pale flesh colour. Its relations to the surrounding strata, 
 however, are considerably obscured by the thick coating of heath and 
 gorse with which these high grounds are covered. So far as it can be 
 examined, it does not appear to call for any special remark. 
 
 Such are the chief felspathic dykes and masses that occur in the 
 Silurian tracts of the present Map. Besides these, however, there are 
 also some which intersect both the Silurian and Lower Old Eed Sandstone 
 strata, while others are confined to the latter series. 
 
 St. Abb's Head consists of a huge boss of felstone, rising to a height of 
 809 feet above the sea, which has worn it iuto ragged precipitous cliffs, 
 full of clefts and caves, and fringed with sunken reefs and skerries and 
 craggy stacks. This felstone is a compact, dull, porphyritic rock, usually 
 of a reddish, sometimes of a blue, colour. It is separated from the 
 adjoining Silurian rocks by a remarkable valley running in a N.W. and 
 S.E. direction from the sea on the one side of the headland to the sea 
 on the other. The highest part of this valley lies at its north-west end, 
 where a mass of clay and shingle rises steeply from the beach to a height 
 of about 75 feet. From this point the slope is gentle towards the cove 
 called Burnmouth Harbour on the south-eastern shore. The sides of the 
 valley are tolerably steep in places, hence St. Abb's Head stands com- 
 jaletely detached from the adjoining high grounds, and thus that the 
 sea once occupied the valley, and that the headland was in consequence 
 an island, is a fact which obtrudes itself at once on the attention. When 
 the geological structure of the locaUty is more closely examined, it is 
 found that the line of the valley runs at nearly right angles to the strike 
 of the Silurian rocks, and that the felstone therefore cuts across the 
 truncated ends of the sti'ata instead of lying more or less in accordance 
 with their direction. This order of arrangement is well seen in the walk 
 from Pettico Wick on the west side of the Head to Horsecastle Bay on the 
 south-east side. Along the northern margin of the valley we see the 
 line of the felstone sharply defined, whUe on its southern slopes the grits 
 and shales, either vertical or highly inclined, present their edges to view, 
 striking in a north-easterly direction at right angles with the boundary 
 line of the felstone. These strata, though a good deal broken, are not 
 6802. c 
 
32 GEOLOGY OP EASTERN BERWICKSHIRE. 
 
 much metamorphosed. As we trace the felstone in a south-easterly 
 dh-ection, we find that it not only cuts across the Silurian series, but 
 penetrates also into the ashy beds of the Lower Old Eed' Sandstone, as 
 may be seen in the range of rugged precipices that foim the west side of 
 Horsecastle Bay. There, however, its boundary is not a straight hne. 
 On the contrary, it sends out into the ash projecting masses, which 
 become inseparably intermingled with the series of felstone bosses, and 
 irregular dykes, to which aUusion has been already made. Hence the 
 rock of St. Abb's Head is certainly of later date than that portion of the 
 Old Red Sandstone series, represented by the ashy sti-ata of Horsecastle 
 Bay. 
 
 From St. Abb's Head to Coldingham Bay the coast has an irregular 
 fringe of felstone, which, as explained in the last chapter, runs in and out, 
 as it were, among the ashy rocks. To what extent either a part or the 
 whole of this felstone is to be viewed as, in a general way, of the same 
 age as the ash, I have no means of determining. That it must, in the 
 strictest sense, be later than the ash which it penetrates is of course 
 sufficiently obvious. J3ut it may nevertheless belong to a part of the 
 same great series of volcanic eruptions to which that ash owes its origin. 
 Like the rock of St. Abb's Head, it differs, at least in most places, from 
 the ordinary character of the felstones in the Silurian tracts. It never 
 shows that compact horny texture and pale yellow or fiesh colour, with 
 granules of quartz, so common among the dykes in the older formation, 
 while it frequently approaches so closely to the character of an ash that 
 its real origin becomes then liable to not a Httle doubt. On the other 
 hand, it is quite true that portions of some of these masses are undis- 
 tinguishable from felstones in the Silurian series. In the meantime, we 
 are destitute of any means of deciding whether or not the felspathic 
 bosses and veins that cut the ashy strata were produced during some part 
 of the volcanic era to which these strata belong. All that can at present 
 be affirmed is, that they are assuredly older than the Upper Old Eed 
 Sandstone of this district, as shown at BeU Hill and Eyemouth, that they 
 ai-e not earlier than the ash, and that they must accordingly belong to 
 some intermediate stage of the great formation of the Scottish Old Red 
 Sandstone. The same remarks hold true of that series of felstones already 
 described as traversing the ash to the west of Eyemouth, and also to that 
 group which occurs in the ash of the Ale Water. That some of the 
 Eyemouth felstones are really coeval with the ash has been indicated 
 above, but others, specially those immediately to the east of Callercove 
 Point, are liable to the same doubt as in the case of the series between 
 St. Abb's Head and Coldingham. 
 
 I have described together the felstones of the Silurian and of the 
 Lower Old Red Sandstone series from the impossibility of rigorously 
 separating them into chronological order. No one, however, can have 
 examined them over a wide area without becoming convinced that the 
 crystalline porphyritic masses of the Silurian tracts are of older date than 
 the dull red lava-like bosses of the Lower Old Red Sandstone, and that, in 
 fact, to a considerable degree, they owe their origin respectively to different 
 sources. With regard to the SUurian masses, several points of interest 
 have been observed in the course of this Survey. 
 
 In the first place, as noticed above, the dykes and veins have a markedly 
 localized distribution ; and this holds true of the whole region of Lammer- 
 muir. 
 
 In the second place, they appear to be most numerous where the strata 
 are most broken and crumpled. If we examine the coast-line west of 
 St. Abb's Head, where the Silurian beds are thrown into endless undula- 
 tions without being so much fractured and irregularly squeezed as in 
 
INTRUSIVE ROCKS. 33 
 
 other parts of the district, we find intrusive points of felstono to be of 
 but rare occurrence. If, on the other hand, we trace the cuttings of the 
 North British Railway near Bummouth, or the cliiF sections to the north 
 of that village, we see a vast number of veins and tortuous dykes tra- 
 versing a series of greatly disturbed strata. Such an association of so- 
 called igneous masses with dislocated strata is commonly regarded as an 
 example of cause and effect, the dykes having been ejected in a molten 
 state from below so as to disrupt, crumple, and metamorphose the rocks 
 through which they passed. It would seem, however, to be nearer the 
 truth to assume the rents of the strata to be the cause of the appearance 
 of the dykes. 
 
 In the third place, the Silurian strata have not undergone the greatest 
 amount of alteration where the dykes and veins are most numerous. 
 This may be readily ascertained by comparing, say, the Bummouth 
 sections, where the felstones are so abundant, with those of the coast at 
 Coldingham Bay, where felstones are rare, but where the grits and 
 shales have been intensely altered. 
 
 In the fourth place, there is a correspondence between an increased 
 crystalline texture of the felspathic masses, and a higher metamorphism 
 of the strata ; in other words, where these masses are most crystalline 
 and granitic, there the metamorphism is greatest. It is only where 
 there is a large area of felspathic rock that we meet with a granitic 
 texture. If there be but dykes and small bosses, we may find some of 
 them made of a crystalline porphyry, but this porphyry does not shade 
 into a true granite. As an illustration of this feature it is enough to point 
 to the case of Cockburn Law and Stonesheil Hill. The granite of Priest- 
 law (Sheet 33) is another, and perhaps stiU better example. A central 
 area of crystalline granite is found to pass into porphyry, which shades 
 almost insensibly into the surrounding grits and shales. In some of 
 the river-courses, as for instance in that of the Fassney Water, it is 
 sometimes hardly possible to decide where the stratified rock ends and 
 the unstratified rock begins. Similar gradations of grit and shale into a 
 felstone occur in the Ale Water. 
 
 From these facts the inference seems a just one, that the felspathic 
 masses of the district have not been the actual cause of the metamor- 
 phism of the Silurian strata. I believe we must seek for a less obvious, 
 but more potent agency," and regard the felstones, granites, and meta- 
 morphosed grits as being but various stages in the same process of 
 change. Into the nature of that process it would be out of place in this 
 memoir to inquire. I merely may remark in concluding this part of 
 the subject, that the metamorphism appears to have been developed, not 
 equally throughout the district, but in points of greater or less extent, that 
 it is most intense where it can be traced into granite as into its ultimate 
 stage, and that it is not dependent upon an abundance of dislocations 
 and intrusive dykes. It was perhaps closely connected with the effects 
 of great vertical and lateral pressure, whereby the strata were com- 
 pressed without actual fractiu'e. Wherever, owing to a failure of this 
 pressure in one direction, the beds have been much broken, dykes of fel- 
 stone have ascended through the rents, but the extent of the metamorphism 
 is not thereby increased, if it be not in some cases really lessened. 
 
 Nothing certain can be said as to the geological age of this meta- 
 morphism, except that it must be older than the Upper Old Eed Sand- 
 stone of the district, since the conglomerates of that formation contain 
 in abundance fragments of the altered strata, with their felstones and 
 granites. It may, perhaps, be older than even the Lower Old Eed 
 Sandstone of Berwickshire. That all the felstones of the Silurian tracts 
 belong to the metamorphic series is not asserted. It may be that some 
 
 c 2 
 
84 GEOLOGY OF EASTERN EEEWICKSHIRE. 
 
 of them, more especially the dull red lava-like varieties, should be classed 
 with those in the Lower Old Eed Sandstone, which they closely resemble. 
 As to the age of the latter series, I can only repeat a previous remark, 
 that as the Upper Old Eed Sandstone of the district covers them uncon- 
 fonnably, they must belong to some intermediate pai-t of that formation. 
 
 In certain localities the Silurian and Old Red Sandstone series are cut 
 through by dykes of greenstone. These, however, belong to a much 
 later period than those described in this chapter, and they will accord- 
 ingly be noticed on a subsequent page. 
 
 CHAPTER V. 
 
 Upper Old Red Sandstone and Conglomeeate. 
 
 If the reader will consult a geological map of Scotland, he will find 
 that the Upper Old Eed Sandstone of the present sheet of the Geological 
 Survey is merely a narrow eastward prolongation of the broad belt of 
 that formation which extends from Dunbar across the Lammermuir 
 Hills to the flanks of the Cheviots. There are two portions delineated 
 here, one on the north side of the Silurian chain at Cockburnspath, the 
 other on the southern flank of the hills running eastward from near 
 Cockburn Law to Mordington Church. As the former area is of very 
 limited extent, and belongs more appropriately to Sheet 33, it will be 
 described in the Memoir to accompany that Map. Nothing, therefore, 
 need be said of it fui'ther than that it is admirably exposed along the 
 cliflTs of the Siccar Point, where its junction with the highly inclined 
 Silurian rocks was first described by Hutton, and afterwards by his 
 biographer Playfair.* 
 
 The band of red sandstone which stretches across from the Lam- 
 mermuirs to the Lamberton Hills rests at either end on steeply inclined 
 Silurian strata, while over the intermediate space it lies unconformably 
 on the ashy bed of the Lower Old Red Sandstone. It is covered by, and 
 graduates upward into the sandstones and shales of the Lower Car- 
 boniferous series, which, by trending towards the Silurian rocks of the 
 Lamberton HiUs cuts off the eastward extension of the red sandstone. 
 Measured across the broadest part, this band does not probably con- 
 tain a thickness of more than 1,000 feet of strata. Hence it can be 
 regarded as representing only a portion of the Upper Old Red Sand- 
 stone of the South of Scotland. It contains the highest beds of the 
 formation, as these begin to shade into the Carboniferous series. That it 
 lies on the same general horizon with the other red sandstones and con- 
 glomerates of Berwickshire, may be inferred from the continuity of the 
 beds, and also from similarity of fossil contents. Various ganoid scales and 
 plates t have been found in the red pebbly sandstones of Prestonhaugh 
 and Cockburn Mill on the Whiteadder, and also in Harelaw Quarry near 
 Chirnside. Portions of the Cyclopteris Hihernicus have also been 
 
 * " Theory of the Earth," vol. i. p. 454 ; Playfeir's Works, vol. iv. p. 78 ; " Illus- 
 trations of the Huttonian Theory," p. 213. 
 
 f The true generic affinities of many of the upper Devonian fishes have still to 
 he determined. At present it is impossible to say with certainty to what fish the 
 remains mentioned in the text may have helonged. Mr. Stevenson of Dunse was 
 the first, I believe, to detect fish-remains in these sandstones (see his paper on Cock- 
 burn Law. Trans. Roy. Soc, Edin., vol. xvi. p. 33). They have also been ob- 
 tained in considerable quantity by Mr. Gibbs and myself during the progress of the 
 geological survey of the district. 
 
UPPER OLD BED SANDSTONE. 35 
 
 met with. But no sooner do we pass up into the grey and pui'plish 
 sandstones and shales of the Carboniferous group, than these organic 
 remains cease, and their place is taken by others which are recognized 
 as truly Carboniferous. We cannot doubt, therefore, that the red 
 sandstones in question belong to the uppermost part of the Old Eed 
 Sandstone series. 
 
 Mr. Milne Holme, in his geological description of Berwickshire,* 
 has endeavoured to show that these sandstones are possibly divisible 
 into tv^o groups, one undoubtedly belonging to the formation below 
 the Carboniferous, the other much more recent, and referable per- 
 haps to the "New Red Sandstone." He grounds this statement 
 on the fact that these strata are for a considerable distance (as in 
 the neighbourhood of BiUy Castle,) nearly flat, that southwards 
 similar red sandstones occur, inclined to the south or south- south-east, at 
 from 5° to 15°, while not far to the west, at Prestonhaugh, they are 
 violently contorted. He infers, therefore, that the inclined series dipping 
 below the Carboniferous strata belongs to the Upper Old Eed Sandstone, 
 while the flat portion may be more recent than the Carboniferous beds, 
 and hence may even be as late as the Permian or Trias. But the dif- 
 ference of inclination between the Billy sandstones and those near 
 Chirnside is not more marked than between contiguous portions of the 
 neighbouring Carboniferous beds, and seems to be of itself much too slight 
 to justify so important a sub-division. Besides, the lithological character 
 of the whole series, whether horizontal or inclined, remains uniform 
 throughout. I believe the same fossils have been found in the one set 
 of strata as in the other. At the same time there seems good reason 
 to surmise that an unconformity does exist , in the Upper Old Eed 
 Sandstone of the south-east of Scotland. The rapid disappearance of 
 the vast conglomerates of Dunbar and the Eastern Lammermuirs, and 
 their replacement by the trifling band of red sandstone at Cockburns- 
 path, are perhaps to be explained by an actual physical break in the 
 succession of beds belonging to this division of the Old Eed Sandstone. 
 T shall enter upon the discussion of this question in the Memoir to 
 accompany Sheet 33 of the Geological Survey of Scotland. 
 
 The basement beds of the Upper Old Eed Sandstone as developed 
 in this district are best exposed along the banks of the Whiteadder at 
 Cockburn Mill.. No better section could be desired to show the 
 relative ages of the Silurian grits, the granite, the red sandstones, 
 and the veins of greenstone. "We gain some insight too into the aspect 
 of the shore along which these sandstones were deposited, and into 
 the character of the fish which lived at the time, and of some of the 
 plants that clothed the neighbouring land. The river has cut its way 
 down through the red beds, and laid bare the surface of Silurian rock, 
 from the waste of which, the conglomerates and sandstones were 
 formed. We see these old reefs and ledges standing out of the waters of 
 the Whiteadder, just as they must have stood out of the waters of that 
 ancient lake or sea, by whose waves their shingly ruins were slowly piled 
 up around and over them. And the shingle is there still ; its angular 
 and rounded pebbles heaped together on every projecting point of rock, 
 as they were left by the last wave that broke among them. They are 
 now no longer loose, but bound up in a stiff red paste, from which 
 the pebbles everywhere protrude. A little further up, the pebbly beds 
 rest directly on the granite, of which they contain fragments, but both 
 here and further down the river, they have undergone a good deal of 
 
 Trans. High, Soc, vol, xi, p. 206. 
 
36 
 
 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 S 
 
 M 
 
 S 
 
 squeezing and fracturing since the time of their deposition, so that 
 their junctions with the older rocks are sometimes not so clear as could 
 be wished.* 
 
 The lower beds of the red sandstone series 
 consist of alternations of breccia, conglomerate, 
 red sandstone, and marl. Where they rest on 
 the underlying rocks, they are made up of 
 angular and rounded fragments of Silurian 
 grit, shale, and granite. Bands of pebbly red 
 sandstone with well-preserved ripple-marks 
 succeed, dipping in a south-easterly direction 
 at about 23°. Among these lie pebbly and 
 breociated beds, sometimes fuU of felspathic 
 balls derived from the neighbouring hill. 
 Layers of red marl next make their appear- 
 ance among the pebbly sandstones and finer 
 conglomerates. A good deal of faulting and 
 contortion of the beds has taken place here ; 
 and a dyke of light reddish-coloured amygda- 
 a loidal greenstone may be seen traversing the 
 2 beds. It is at this point, between the dyke and 
 ° _ Cockburn Mill, that the fish scales occur. They 
 § 3 lie in a red marly conglomerate, and are only in 
 g 2 a fragmentary state. At the little cottage of 
 g .3 Prestonhaugh red fissile sandstones with ripple- 
 '^ S marks and seams of sandy marl are seen in the 
 "^ i bed of the Whiteadder, dipping first east by 
 ^^ north, and then turning round towards the 
 ^ ° south-east at 18°. Some coarse sliingle now 
 .2 J occupies the bed of the stream, but at the foot 
 ^ B of the high wooded banks on the south side of 
 & g the river-course, highly inclined Silurian rocks 
 pq /•V.\;V ^ '^ again make their appearance. These can be 
 
 traced along the bank in a north-westerly direc- 
 tion, until at the foot of the Birkenside Burn 
 they join the main Silurian mass of the Lam- 
 mermuir chain. They form in short a long 
 tongue of Silurian strata running out into the 
 red sandstone series. Their south-eastern ex- 
 tremity, as shown in the bed of the river, is 
 overlaid by some red sandstones and marls dip- 
 ping down the stream, at 17° to 20°, and con- 
 taining numerous fragmentary scales and plates 
 of the same fish which occur at Cockburn Mill. 
 As the beds are traced eastward they become 
 more steeply inclined, the angle rising even to 
 as much as 60°, while several distinct fractures 
 may be seen running across them. At the east 
 end of the section here laid bare, the beds have 
 a S.S.W. dip at 27°, so that there is probably 
 not a little squeezing and displacement. 
 
 Nothing further is exposed along the river 
 until, at the bend due south from Primrose Hill, a bed of green felspathic 
 ash occurs. This volcanic rock forms here the boundary between the 
 
 9^ 
 
 See Mr. Steveiuon's paper, already cited. 
 
UPPER OLD BED SANDSTONE. 37 
 
 Upper Old Red Sandstone and the basement of the Carboniferous series, 
 for immediately to the east it is covered in regular sequence by white 
 and greenish sandstones and shales, with weU-marked carboniferous 
 plants. The amount of shingle in the Whiteadder throughout this 
 part of its course tends in some degree to obscure the general relations 
 of the rocks. But all doubt of the order of succession is removed 
 by a visit to the stream which descends from the Hardens Hills to the 
 south-west of Dunse Law and Borthwick Hill. The red and grey 
 sandstones which there form the top of the Upper Old Eed series, 
 are seen dipping towards the south-east at a point about 650 yards 
 to the N.E. of the farm of Hardens. Above them comes a band of 
 reddish felspathic ash distinctly stratified with red sandy layers and 
 balls of whitish sandstone. The ash is succeeded by some grey sandstone 
 and black sandy shale fuU of plant-remains, and undoubtedly belonging 
 to the carbonijferous group. On both sides of the great semicircular 
 ridge of Dunse Law this ash-bed is thus seen to occupy the same position. 
 It appears to be wanting, however, between the two localities ; at least it 
 is not seen sweeping round by the town of Dunse, and hence the original 
 point of connexion between the bed in the Whiteadder and that in the 
 Hardens Valley has been removed by denudation. The rock certainly 
 does not reach far to the east, for in the Cumledge Burn and in the 
 transverse sections laid bare by the streamlets that fall into the White- 
 adder from Billy Burn, it is wholly absent. As developed in the 
 Whiteadder near Primrose Hill, it is a greenish felspathic rock, full of 
 angular and more or less rounded fragments of greenstone and Silurian 
 grit. A bed of columnar porphyritic greenstone, with an easterly dip 
 and a remarkably scoriaceous aspect in some parts of its mass, lies in 
 the ash, forming the picturesque crag at Angermyhart. A smaller and 
 much less observable patch of light-coloured highly amygdaloidal and 
 porphyritic greenstone occurs in the ash a short way further down the 
 stream. Owing to a bend of the Whiteadder at this point, the ash 
 quits the channel, and runs on southward, while the white and greenish 
 sandstones at the bottom of the carboniferous series are exposed dipping 
 away from the ash, first in a north-easterly direction and then due 
 north, as the whole of the beds trend round again towards the river. 
 By this change in the direction of dip, the ash is again exposed on the 
 south side of the water close to Preston Bridge. The red sandstones 
 which underlie it are seen on the steep bank, while a greenstone which 
 lies above it forms the foundation for the southern limb of the bridge. 
 Inunediately beyond this, in the bed of the stream, the white and yellow- 
 ish sandstones containing plants are again seen, and from this point the 
 whole of the rest of the course of the Whitadder runs upon strata of 
 carboniferous age. The greenstone of Preston Bridge occupies certainly 
 the same position as that at Angermyhart, but they do not appear to be 
 continuous. From the bridge, however, the rock seems to extend to 
 Cumledge Burn, for in the ravine of that streamlet the red sandstone 
 series is separated from the carboniferous sandstones and shales by a 
 bed of greenstone, the strata above and below which dip N.E. at from 
 32° to 40°. This rock towards the bottom is of a purplish fine-grained 
 textm-e, and full of joints, whose surfaces are coated with serpentine. 
 Higher up a marked amygdaloidal structure is observable, the cavities 
 being to a considerable extent filled with green earth. ' Between the 
 point, where this greenstone crosses the burn, and the margin of the 
 Whiteadder carboniferous sandstones occupy the rest of the ravine. 
 
 From Preston Bridge eastward the boundary line between the Old 
 Eed Sandstone and the overlying formation runs parallel to the White- 
 adder, and is here and there cut across by the streamlets which descend 
 on the north side of that river. No very clear sections of the passage 
 
38 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 beds, however, occur in. any part of this tl'act. The streams which best 
 expose the rocks are those in the neighbourhood of Foulden, but eveil 
 there some obscurity exists, arising partly from occasional patches of 
 drift and soil, and partly from the high inclination and fractured state 
 of the strata. Yet the general relation of the red sandstones below to 
 the white, grey, and yellowish sandstones and variously tinted shales 
 above cannot be missed. The palseontological differences between the 
 two groups of strata, though comparatively shght, can yet be detected 
 along this line. Thus in the red sandstones of Harelaw Quarry rugose 
 plates and scales of those holoptychius-like ganoids of the Upper Old 
 Ked Sandstone occur,* to which reference has already been made, while 
 due south from this locality, in the carboniferous shales on the banks of 
 the Whiteadder at HuttonhaU Mill, scales of the characteristic Lower 
 Carboniferous Rhizodus Hibberti may be obtained. 
 
 A reference to the Map will show the great variation in the thickness 
 of the band of Upper Old Eed Sandstone. The beds must have been 
 deposited on a very uneven bottom, and in a descending area. Hence, 
 outlying patches now occur scattered over the older rocks at much 
 higher levels than those of the strata just described. There is^ in short, 
 good evidence to show that the whole of at least the eastern part of the 
 Lammennuir chain was covered at one time with the conglomerates and 
 sandstones of this formation. To this day the conglomerate ascends to 
 a height of 1,345 feet above the sea in Monjmut Edge (Sheet 33). 
 Whence we may safely infer that it once extended eastward over the 
 lower grounds. That it reached away out into the area now occupied by 
 the German ocean is proved by the denuded cliffs of red sandstone and 
 conglomerates at Cockburnspath, and by several outliers scattered over 
 the high grounds that border the sea from St. Abb's Head, almost as far 
 as the gates of Berwick. 
 
 It is these outliers which now fall to be described. They are seven in 
 number, exclusive of the one on the Cockburnspath shore. Beginning at 
 St. Abb's Head, and proceeding in a south-easterly direction, the first that 
 we encounter is the patch of conglomerate previously referred to as forming 
 Bell Hill. It lies on the edges of the Silurian and Lower Old Red Sand- 
 stone ashy strata, in an oblong ridge with a length of about 600 yards, and 
 a breadth of 350. At its south-eastern margin it overhangs the cliff of 
 Halterem's Loup, the base of which is washed by the waves. The rock 
 of this outlier is a conglomerate, sometimes approaching a breccia, made 
 up of fragments of the underlying Silurian grits. Measured at Halterem's 
 Loup it somewhat exceeds 150 feet in depth, its base being there about 
 100 feet above the sea, while the summit of Bell Hill is 257 feet. 
 
 The next outlier is that Avhich caps the north-western pi-omontory of 
 Eyemouth Bay, on the headland called the Fort. It consists of a well- 
 
 Fig. 7. 
 Sketch- Section across the Fort and Bay of Eyemouth. 
 
 THE FORT 
 
 a Lower Silurian Grits and Shales. b Lower Old Red Sandstone Ash and Felstone. 
 c Upper Old Red Sandstone and Conglomerate. /Probable Line of Fault. 
 
 * A fine specimen of Bothriolepis ornata was obtained from this quarry by the 
 Geological Survey, 
 
UPPER OLD RED SANDSTONE. 39 
 
 marked conglomerate, sometimes more or less brecciated, derived chiefly 
 from the waste of the felspathic rocks on which it rests. Its jmiction 
 with the underlying masses is well seen along the side of the cliif, espe- 
 cially On the north, where the sea by scooping out deep narrow creeks, 
 has isolated portions of the felstone into rude sea^stacks, which stand up 
 with a capping of conglomerate. The surface of the felstone on which 
 the derivative beds repose is worn and uneven, and must evidently have 
 been so previous to the deposition of these beds. No one can doubt, even 
 though the felstones show no trace of bedding, that the conglomerate 
 covers them unconformably and belongs to a much later age. These 
 conglomeratic strata have a gentle dip to the north, so that while on the 
 south side of the fort their base rests on the top of the cliff, at the north 
 side they descend into the Sea. They are there well exposed in flat ledges 
 between tide-marks, while a little further west they may be seen pic- 
 turesquely capping an isolated stack of the underlying igneous rocks. 
 Some parts of the series are remarkably firm and compact, insomuch 
 as to be used in the construction of the Eyemouth harbour, as well 
 as in several houses and walls.* It is not a little curious to see along 
 the sides of the pier these blocks of conglomerate, made up as they are 
 of mere rounded pebbles, yet able to withstand all the fury of the easterly 
 gales that from time to time burst into the Bay of Eyemouth. 
 
 The next outlier to the south is so small and so inaccessible as easily to 
 escape notice. It overhangs the summit of the sea-cliff to the south of 
 Eyemouth at a point called Hawk's Heugh, where the precipice rises to 
 a height of 300 feet above the waves. A dark trap -dyke here runs up 
 the face of the cliff, but on reaching the top it is covered over by a patch 
 of felspathic breccia, derived perhaps from its detritus. Only a few 
 square yards of this breccia are visible^ lying on the decKvity that slopes 
 northward from the highest part of the cliff at Bleak Heugh. 
 
 In the glen of Burnmouth, where its north side forms a steep bank 
 between the bend of the Partanhall road and the space immediately 
 above high-water mark, lies a small patch of what is probably a con- 
 glomerate of the same age as those just described. It adheres to the side 
 of the hill and consists of a mass of angular fragments of grit and felstone 
 of all sizes cemented in a reddish clayey paste. It bears a close resem- 
 blance to the conglomerate outliers of Lamberton and Scuddylaw. It is 
 possible, however, that this mass of angular debris has been derived in 
 later times from the decomposition of the overhanging rocks. A few 
 yards higher up, iu the bottom of the ravine, there are two blocks of a 
 breccia which consists of angular fragments of pink felstone cemented by 
 calcareous tufa. The fragments may have been derived from some of the 
 felstone dykes which traverse this glen, though I saw no calcareous in- 
 crustations now in progress in any part of this locality.^ 
 
 Perhaps the most striking outUer in the whole district, so far at least 
 as its position is concerned, is that which chngs to the side of Chester 
 HiU about half a mile south from Burnmouth. It looks out upon the 
 sea from a height of 560 feet, the bared ends of its pebbly strata rising 
 towards the north-east, and pointing with a significance that cannot be 
 mistaken to the enormous denudation which this part of Scotland has 
 undergone since the deposition of the Upper Old Eed Sandstone. Along 
 the precipice which forms the north-east side of Chester Hill these 
 
 * Mr, Milne Home, writing in 1835, remarks that the sea wall of the harbour, 
 which was built out of this conglomerate, had not needed repair for the preceding 
 fifty years. 
 
 t See Milne Home, Trans. High. Soc, xi. p. 225. 
 
40 
 
 GEOLOGY OF EASTEBN BEEWICKSHIEE. 
 
 a 
 
 c3 
 
 -a 
 
 O 
 
 o 
 
 o 
 
 a 
 
 3 
 O 
 
 
 PR 
 
 
 strata are clearly exposed. Sandy and 
 well-bedded in the lower layers, and dip- 
 ping W.S.W. at 8°, they become in the 
 upper part a coarse brecciated conglome- 
 rate consisting of fragments of Silurian 
 grit and felstone. Owing to the depth of 
 soil to the west and south, the area occu- 
 pied by this outlier can only be approxi- 
 mately ascertained. It probably does not 
 cover a space of more than 550 or 600 
 square yards, and its visible thickness is 
 perhaps about 70 or 80 feet. 
 
 The next outlier occurs rather more 
 than a mile to the south-east. It caps the 
 cliff overhanging Lamberton Fishery, and 
 has been cut through by the railway. It 
 consists of a very coarse brecciated con- 
 s ^ glomerate entirely derived from the grits, 
 ^ -g shale, and felstones of the Silurian series 
 'S^ on which it rests. At the north end it 
 S a contains some well-stratified beds Gf pebbly 
 "I sandstone, but with this exception there 
 jj S is a singular absence of stratification, the 
 g included fragments of all sizes being heaped 
 a together like the boulders in some parts of 
 ■3) the Boulder Clay. So sti'ong indeed was 
 § the resemblance of this conglomerate to 
 ^ parts of the Drift, that I examined Garc- 
 ia fully the surface of almost eveiy pebble 
 ^ and stone exposed for some yards along 
 
 the Eailway section, in the hope of finding 
 I, some of them covered with sti'iations. But 
 ^ the search proved unsuccessful. On the 
 <i top of the bank lies a thin layer of drift 
 
 gravel, in which the boulders, chiefly de- 
 ,| rived from the underlying conglomerate, 
 3 are frequently covered with ordinary glacial 
 ^ strise. But as soon as we peneti'ate down- 
 
 1 ward into the pateozoic rock these strije 
 ° disappear. The conglomerate boulders are 
 g very generally covered with a greenish or 
 
 reddish glaze, which can be scratched with 
 the nail, and is of the same argillaceous character as the general matrix. 
 At the head of the little bay at Lamberton Fishery, a mass of beautiful 
 flesh-coloured porphyritic felstone, in the Silurian series, is covered by 
 this conglomerate, which indeed is largely made out of its detritus. So 
 that here, as well as over many parts of this district, there is demonstra- 
 tive evidence that the pale porphyritic and quartziferous dykes and bosses 
 in the Silurian strata belong to a more ancient era than that of the Upper 
 Old Eed Sandstone. It wiU be seen from the map that the great fault 
 already alluded to skirts the eastern margin of this patch of conglomerate, 
 and separates it from the highly inclined sandstones of the Carboniferous 
 series. 
 
 The last and probably the largest of all the outliers of this foi-mation 
 shown on the present Map is that which flanks the Silurian hills between 
 Marshall Meadows and the Steps of Grace. The extent of its area, owing 
 to the drift-covered character of the ground, cannot be exactly ascertained. 
 
 r3 
 
 o 
 
 a 
 
 o 
 
 o 
 
 to 
 CZ2 
 
CARBONIFEROUS FORMATION. 41 
 
 But it is well exposed in the ravine between the Berwick Water-works 
 Reservoir and New East Farm. Throughout a great part of its mass 
 it closely resembles the coarse brecciated unstratified conglomerate of 
 Lamberton. Its included fragments are often quite angular, and of con- 
 siderable size, especially in the lower parts of the stream. Higher up 
 they are of smaller dimensions, and assume a more bedded aspect, the 
 strata dipping at a high angle in an E.N.E. direction. Silurian grits 
 occupy the bed of the water-course before we reach the Reservoir. From 
 the steep inclination of the conglomerate, it must have undergone consider- 
 able disturbance since its deposition, and in this respect may be compared 
 with the highly-tilted sandstones of the Whiteadder at Prestonhaugh. 
 The eastern edge of this outlier, like that of Lamberton, is bounded by 
 the same long line of dislocation. 
 
 In conclusion, the position of these outliers renders it probable that 
 the whole of the eastern part of Berwickshire was at one time covered 
 with strata of Upper Old Red Sandstone age. Their coarse brecciated 
 and unstratified character at Lamberton and Marshall Meadows indi- 
 cates an origin different from that of ordinary water-worn sediment. 
 Possibly ice may have had some share in the production of a mass of 
 detritus which so closely resembles parts of the Boulder Clay, or it 
 may be that these conglomerates represent the results of a subaerial waste, 
 of which the products were accumulated, without suifering much from 
 wave-action, along the margin either of lakes or of the sea. 
 
 CHAPTER VI. 
 
 CAEBONirEEOUS FORMATION. 
 
 The band of Old Red Sandstone which flanks either side of the 
 Lammennuir chain passes u^j into the sandstones and shales of the Car- 
 boniferous group. On the north-west side we see the gradation well 
 exposed along the shore at Cockburnspath, but this small area, as already 
 explained, comes more appropriately into the Memoir descriptive of Sheet 
 33. The passage beds between the two formations along part of the 
 southern margin of the hills, and also a considerable portion of the lower 
 members of the Carboniferous series, are shown on the present Map. 
 These strata occupy the southern edge of the Map, extending down the 
 course of the Whiteadjier from Preston Bridge to the sea. Owing to the 
 large fault, which runs N.N.W. fi-om Berwick, they are also prolonged 
 on the coast as far as Bummouth. No outliers occur in any part of the 
 district. 
 
 Arranged in descending order, the succession of Carboniferous strata is 
 as follows : — 
 
 Base of Carboniferous r^-v^^"^, sandstones with two bands of fossiliferous 
 Limestone - 1 limestone, and two or three tmn coal seams, total 
 
 " L thickness shoivn on this Map probablyunder SOOfeet. 
 " Calciferous Sand- r2. White, yellow, grey, and reddish sandstones, with 
 stones," = Lower I alternations of green, blue, and lilac shales and bands 
 Limestone Shales j of " cement-stone." Total thickness perhaps about 
 of England. u 3,000 feet, passing down into — 
 
 3. Upper Old Red Sandstone. 
 Calciferous Sandstones.* — The series marked No. 2, graduating 
 
 * !rhis term was originally proposed ty Mr. Charles Maclaren to include the great 
 group of beds -which in the Basin of the Forth are intermediate between the Carbo- 
 niferous limestone and the top of the Old Red Sandstone. The name has not been 
 generally adopted ; but in working out the geology of Central Scotland I have found 
 
42 GEOLOGY OF EASTERN BERWICKSHIEE. 
 
 upward from the Old Eed Sandstone, is that which falls to be first 
 described. Its base is seen in the Whiteadder at Preston Bridge, in the 
 Cumledge Burn, in Billy Burn, and in several of the streams which 
 descend into the Whiteadder from the high ground between Chimside 
 and Mordington. These lower beds consist of white and reddish sand- 
 stones, sometimes with partings of clay or shale. They not uncommonly 
 contain fragments of calamites, and fern-stems of recognizable Carbo- 
 niferous forms. Bands of coarse argillaceous limestone, or "cement- 
 stone," as it is termed, occur in this undeimost part of the Carboniferous 
 system, as at Ninewells, near Chii-nside, and in the streamlet between 
 Mordington Bridge and Edrington House, but they become more 
 abundant higher up in the series. 
 
 The sandstones at the bottom of the group pass up into a remarkable 
 series of sandy shales in rapidly alternating bands of various shades of 
 green, grey, blue, and a kind of lilac colour. Ordinary black argillaceous 
 shale is of rare occurrence. In these respects the lower Carboniferous 
 strata of Berwickshire are strongly marked off from those on the north- 
 west side of the Lammermuir chain, where such shales as those of the 
 Whiteadder sections are absent. They contain frequfet bands of sand- 
 stone, often full of Carboniferous plants, and also numerous seams of an 
 impure, sometimes nodular, limestone or " cement-stone." Gypsum also 
 occurs in partings between the ,shales, as along the south side of the 
 Whiteadder, near AUanton, while according to Mr. Milne Home, some of 
 the springs which rise through these strata contain an appreciable quantity 
 of salt. This alternating series of shales, sandstones, and Hmestones is 
 laid bare in many fine sections along the course of the Whiteadder ; those 
 at Chimside Bridge, AUanton, Edi-ington Mill, Hutton Mill, and Ed- 
 rington Castle, and those in the tributary streamlets between Foulden and 
 Mordington, may be especially noticed. To one who has famUiarized his 
 eye with the character of the Lower Carboniferous strata of the Lothians 
 and Fife, there is something altogether peculiar in those of Berwick- 
 shire. Among ' the latter, he misses the massive deposits of white 
 sandstone which form so marked a feature at Dunglass, Craigleith, 
 Binny, CuUalo, and elsewhere. He fails also to detect such thick zones 
 of finely laminated black shale as occur at Wardie and Queensferry ; 
 indeed he can hardly detect any black shale at all. While in the 
 Lothians, the prevailing character of the strata is marked by thick 
 bands of white, yellow, or grey sandstone, separated by beds of black 
 shale, often of considerable depth ; in Berwickshire the strata are 
 individually of much less thickness ; they alternate rapidly with each 
 other ; so much so, that some of the sections almost remind one of the 
 finer alternations of the Lias. They are, moreover, usually pale in 
 colour, and more or less sandy throughout, fissile bituminous shale 
 being, so far at least as I have observed, almost entirely wanting. 
 The shales, in short, very commonly deserve the name of sandy marls 
 or mudstones. The Berwickshire series differs further from that of the 
 Lothians in the great abundance of its thin limestone bands. In the 
 latter district, limestone is by no means uncommon, but it occurs for 
 the most part in widely separated beds of seldom less, and usually 
 more, than a foot in thickness, and it is commonly of a compact, semi- 
 crystalline, almost horny texture. In the Berwickshire ai-ea, the 
 
 it so convenient that I have used it for some yeai's. Nor is its local conyenieuce its 
 only recommendation. Seizing the occurrence of hands of cherty limestone as a 
 distinguishing stratigraphical featme, it serves to link together a great natural group 
 of strata in the Lothians and Fife, and enables us to put these in parallel with the 
 corresponding portion of the Lowei; Carhoniferous series of England and Ireland. 
 
CARBONIFEROUS FORMATION. 43 
 
 limestones are of a grey or yellowish tint, of a dull earthy texture, 
 usually only a few inches thick, and they succeed each other so quickly 
 that sometimes a dozen seams or more may be counted in one river-cliff. 
 
 I have reserved for more detailed description the section which has 
 been laid bare by the waves on the coast at Burnmouth. Here a depth 
 of 2,500 feet of strata may be examined, from the lowest limestone 
 of the Carboniferous Limestone group down to the beds which abut 
 against the great fault. We do not see at this point the base of tho 
 series, for the effect of the dislocation has been to throw it out ; nor is 
 it possible to estimate exactly the amount which may be absent. I do 
 not believe it exceeds a depth of 500 feet, which may be supplied from 
 the Whiteadder sections. Taking the section as it stands, we find that 
 its strata, owing to the fault, are nearly vertical throughout. Those 
 nearest the fault are actually reversed, so as to dip in a westerly direc- 
 tion at an angle sometimes as low as 55°. Between the village of Ross 
 and Ross Point they become vertical, and then incline at high angles 
 towards the east. Hence the length of a horizontal section, measured 
 across the edges of the beds at a right angle to the strike, very nearly 
 represents their actual thickness. They run in long parallel covirses, 
 the harder sandstones forming lines of reef along the shore, while tho 
 softer marly beds are occupied by pools of sea-water, or covered with 
 tangle and stones. 
 
 Beginning then at the beds which seem to dip at the fault behind the 
 village of Burnmouth, we meet with some bands of reddish white and grey 
 sandstone, separated by zones of greenish and reddish marly shales. The 
 latter are occasionally of a dark grey colom-, and contain fragmentary 
 plants, spirorbis carbonarius, and scales of amblypterus and palcBoniscus. 
 These strata are well exposed on the steep bank overhanging the harbour, 
 and also on the beach at the pier. There the marly shales, with their 
 associated seams of cement-stone, are seen graduating into shaly sand- 
 stones, followed by some distinct bands of white sandstone with shale- 
 partings, on which the Burnmouth houses are built. The zone of 
 marly shales which succeeds contains a thin seam of impure limestone 
 (full of anthracomya, Edmondia, &c.), which may be traced along 
 the shore, its vertical edge forming a narrow and scarcely perceptible 
 ridge in the softer strata, until it ascends the cliff at the west end of 
 the village of Ross, where its weathered surface exposes its fossil 
 contents. 
 
 From this limestone a continuous ascending section can be examined 
 eastward, both along the face of the cliff and on the beach, up to the 
 base of the Carboniferous Limestone. It consists of the same alter- 
 nation of green, grey, and reddish mudstones, or marly shales and 
 cement-stones, with bands of hard grey, reddish, and white sandstone. 
 These mudstones exhibit here, in a characteristic way, the features 
 which distinguish them from the ordinary shales of the Carboniferous 
 group of the Lothians. They are exceedingly fine-grained, compact, 
 shivery, breaking into the rudely spheroidal nodules, and with the semi- 
 conchoidal fracture peculiar to such bands of non-fissile argillaceous 
 matter. They rapidly alternate in beds of varying colours and hard- 
 ness. Sometimes thin partings of sandstone, from two or three lines to 
 two or three inches in thickness, occur in the marl. Such interrup- 
 tions, however, are not frequent ; the strata are mainly argiUaceous, 
 though they often become sandy in texture and full of mica, especially 
 m the greenish bands. Thin veinings of gypsum occur sometimes 
 parallel and at other times oblique to the planes of bedding. These 
 strata, whether marls, cement-stones, or sandstones, are, as a whole 
 singularly destitute of fossijs. ' 
 
44 GEOLOGY OF EASTERN BERWICKSHIEE. 
 
 I cannot quit the description of this group of strata without alluding 
 to one of the best inland sections in which they are displunged. It 
 occurs at a bend of the Whiteadder at Eaven's Knowe, about a mile 
 due south from Mordington Church. A thick mass of sandstone, 
 forming the eastern bank of the river on which the ruins of Edrington 
 Castle stand, begins in its lower part to be seamed with layers of grey 
 and dark red ferruginous marly shales, and then it slowly passes down 
 into a thick shaly or mudstone series, like that along the "Whiteadder at 
 Edrom and Chirnside, or like parts of the Burnmouth coast-section. 
 This set of beds consists for the most part of a dull grey sandy mud- 
 stone, arranged in thin bands from a foot or so in thickness down to 
 the merest films. Some bands contains numerous plants, others of the 
 sandier kind are full of vertical worm tubes, while some abound in 
 cyprides and the little spirorbis carbonarius, anthracomya, and frag- 
 ments of Rhizodus Hibberti. Pale yellowish bars of a fine shivery 
 mudstone, others of an earthy cement-stone, run along the cliif. Towards 
 the base of the series green and pm-plish tints become conspicuous, the 
 beds there are thinner, and the different tints alternate more rapidly. 
 Seen from a little distance nothing can be more striking than the perfect 
 ribbon-like regularity of the bedding of these pale grey and yellowish 
 strata, and the sharpness with which it is marked off by the alternating 
 colours. The section has a strong resemblance to those vast groups of 
 calcareous lacustrine strata which are laid open in the numerous river- 
 courses round Le Puy en Velay in Central France. 
 
 More may be expected to be known of the origin and fossil contents 
 of this series of rocks when the remainder of the great Berwickshire 
 plain comes to be examined in the course of the Geological Survey. 
 At present the best continuous section with which I am acquainted is 
 that of Burnmouth, but, as above explained, the base of the series is 
 there wanting. If we proceed from the basement beds, as shown in the 
 Whiteadder, we cannot, owing to the undulating nature of the strata and 
 the direction of the river-course, obtain a greater thickness in any con- 
 tinuous sections than about 1,200 or 1,300 feet. That is the probable 
 depth of strata along a line drawn from the Old Red Sandstone, at 
 Foulden Bridge, to near Paxton. The section down Foulden Bum 
 from Foulden Mill to Hutton Bridge shows a depth of strata of about 
 800 feet. From the same Old Red Sandstone boundary, at Cruicksfield, 
 to the bank of the Whiteadder, at the head of Blanerne Haugh, there is a 
 thickness of about 500 feet. So that along the whole course of the 
 Whiteadder, notwithstanding its numerous cliff-sections, the actual depth 
 of Carboniferous strata falls considerably short of 1,500 feet. Of these 
 strata the lower parts are wanting in the Burnmouth section. It seems 
 probable, however, that before we have advanced more than 500 or 600 
 feet upward from the base of the formation, as shown in the localities in 
 the valley of the Whiteadder, we begin to meet with the lower parts of 
 the Burnmouth series. If this be true we cannot add more than about 
 500 feet to that series, and this will give a total of 3,000 feet as the 
 thickness of the Calciferous sandstones, or that lower part of the Car- 
 boniferous formation which underlies the Carboniferous Limestone, and 
 represents the Lower Limestone shales of the English counties. 
 
 Carboniferous Limestone. — ^At Hilton Bay and Lamberton the highly 
 inclined strata which extend eastward from Burnmouth are overlaid by 
 a band of limestone, full of lithostrotion, produetus giganteus, &c., 
 which may be taken as the base of the Carboniferous Limestone group, 
 seeing that it serves to divide two groups of strata very distinct litho- 
 logically, and even capable of separation by a comparison of organic 
 
CAEBONIFEEOtrS FORMATION. 45 
 
 remains. Besting on this bed as a base line lies a thick series of 
 red sandstones, with one or two coal seams in the lower part. These 
 are overlaid by a group of limestones, dark shales, sandstones, and coal 
 seams, of which the lower members occur along the shore at Berwick. 
 But this part of the coast-line is traversed by numerous faults and 
 curvatm-es of the strata, which are beautifully shown on the beach. 
 Hence the detailed order of succession cannot be made out until the 
 limestone series of Northumberland, where the whole order is well 
 exhibited, comes to be worked out in" detail. In the meantime the lower 
 part of the Carboniferous limestone of this district may be classified 
 in descending series, thus : — 
 A thick group of limestones, shales, sandstones, and thin coals, seen at 
 
 Meadow Haven, and between Berwick Pier and the King's Mount, 
 
 whence they undulate northwards to the Sharper Head, and southward 
 
 into the English Border. 
 Red sandstones and bands of shale seen in horizontal beds along the coast 
 
 cliffs from Sharper Head northward to Lamberton. Thickness fully 100 
 
 feet.* 
 Lamberton limestone, 1 to 3 feet thick, full of carboniferous limestone 
 
 fossils. Below this bed comes the thick series of sandstone and marl 
 
 already described as the equivalents of the Lower Limestone Shales. 
 The Lamberton limestone is usually a dull brownish yellow or red- 
 dish iron-stJined rock charged with bunches of lithostrotion junceum, 
 chmtetes tumidus, alveolites depressa, productus giganteus, and other 
 characteristic fossils. As shown in the little gully behind the fishing 
 station, it consists of two bands with at least two seams of coal. But 
 the proximity of the great fault and the quantity of debris which 
 covers the declivity tend to obscure the rocks below. In Hilton Bay 
 the strata are well shown, both on the beach and in a prominent cliff 
 which here protrudes its wasted rocks into the ocean. We see how the 
 fault by which these carboniferous deposits have been depressed has 
 not only tilted them on end, but has actually reversed their inclination, 
 so that the upper surface of one bed rests on the under surface of its 
 neighbour. That this is the true arrangement cannot be better shown 
 than by the band of limestone which runs out as a reef in the centre of 
 the bay. For if this bed be examined it will be found that the bunches 
 of coral are all lying with their roots upward, a position which is only 
 explicable by admitting that the bed itself has been turned over. East 
 from this only a few yards the strata are quite vertical, and then in the 
 outstanding cliff just alluded to they right themselves with remarkable 
 rapidity, so much so that at the seaward end of the cliff the inclination 
 is no more than about 8° or 10°. (See sketch section engraved on the 
 Map.) 
 
 The Lamberton limestone rests on coal, and another coal-seam occurs 
 a few feet lower down. But these seams are not of sufficient value to 
 repay the cost of extraction. Several pits have been sunk to them, 
 and ingoing eyes may be seen at different places along the coast, as at 
 Marshall Meadows Bay and Megs Dub. Mr. Christie, the last tenant 
 who tried to work these coals, and to whom I applied for information 
 regarding them, wrote me as follows : — " You will observe," he says, 
 " a thin coal in the face of the rocks, near the sea mark, opposite 
 " where the pits were sunk. I drove a level in that coal up to the 
 " eastmost pit, and sunk the pit about 20 fathoms to the coal below, 
 
 * It is, I think, this zone of red sandstone which, sweeping to the south-west of 
 Berwick-on-Tweed, forms the prominent ridge to the south of the river at Longrldge, 
 Shoreswood, &c. 
 
ft. 
 
 in. 
 
 - 1 
 
 8 
 
 - 2 
 
 
 
 - 1 
 
 4 
 
 46 GEOLOGY QF EASTERN BERWIOESHIRE. 
 
 " which latter was the only coal we wrought. The seam was divided 
 " into two leaves as follows : — 
 
 Bough coal . , . - 
 
 Fire clay, very fine in quality 
 Hard coal 
 
 Total thickness of working - 5 
 
 " There was no other seam but this wrought on the ground, and as it 
 " had a fire-clay roof of about 6 feet, it was a very troublesome and 
 " expensive coal to work. The quality was a^so inferior, the thick 
 " leaf being mixed with sulphur ; in short, the whole concern turned 
 " out so unprofitable that it had to be abandoned after a considerable 
 " outlay of money. To the west [north] of the colliers' houses, in a 
 " field half-way betwixt the turnpike road and the railway, a yellow 
 " limestone of about 4 feet thick was found and opened up. It proved 
 " to be of good quality, but as the seam did ilot hold regular, it was 
 " also given up." 
 
 There is a belief in the district that these Lamberton Coals ovei'lie 
 those of Scremerston, and that if the pits were sunk to a sufficient depth 
 a valuable coal field might be opened up. But there could hardly be 
 a greater error. The Scremerston seams lie up among the limestones 
 of which the lower part is seen at Berwick, while those of Lamberton 
 lie associated with the very lowest limestone of the series. No pit, 
 therefore, could by any possibility reach the Scremerston Coals at 
 Lamberton. 
 
 There is another misconception, not confined to this district, but 
 common among geologists, that these Berwickshire Coals lie below the 
 true Carboniferous limestone, and so difier from even those of the north 
 of England. This however is disproved by the fact that they lie along 
 with a limestone full of the characteristic fossils of the Mountain Lime- 
 stone. They do not therefore difier in position from the edge coals of 
 Midlothian, or the coals which throughout the whole of central Scotland 
 occur at the base of the Carboniferous Limestone series. So far as I 
 have yet observed the strata below that series in Berwickshire do not 
 contain coal.* 
 
 Advancing southwards fi'om Lamberton along the coast-line we find 
 that the fault retires from the sea, and then runs nearly parallel to the 
 shore at a distance varying up to three quarters of a mile. By this 
 means the strata are allowed to range along the sea margin in beds 
 almost completely horizontal — a position which has given rise to a hne 
 of steep indented chff of neaiiy uniform height. The Lamberton lime- 
 stone thus runs along the face of the escarpment, following all the 
 sinuosities of the coast-line for upwards of two miles. It is especially 
 conspicuous in the magnificent cliff" of Marshall Meadows Bay, which 
 rises perpendicularly for 150 feet from the beach. (See section on 
 Map.) 
 
 The soft shaly strata below the limestone have in some places been 
 undermined, and the overlying red sandstone has slid down in huge 
 masses upon the shore. At St. John's Haven the limestone descends to 
 the beach, where its surface has been well exposed by the surf. From 
 this point the remarkable group of red sandstones which separates this 
 limestone from tliose of Berwick occupies the whole of the cliff". These 
 
 '^ Mr. Milne Home refers to several instances of an vmsuceessful search for coal in 
 the calciferoua sandstone group of Berwickshire. Trans. High. Soc, xi. 199. 
 
IGNEOUS ROCKS. 47 
 
 sandstones are full of false-bedding and have a rich red tint mingled 
 with bars and streaks of a golden yellow. They weather out into 
 every conceivable form of cleft, and cave and creek, basin and skerry, 
 and sea-stack. The process of waste among such strata forms a subject 
 of study by itself, and nowhere could it be more advantageously pursued. 
 We see here how sea and air, frost, and rain and springs have acted to- 
 gether in wearing away the rocks, and how their agency has sometimes 
 been accelerated, sometimes retarded, by the structure of the rocks them- 
 selves ; how the waste has gone on rapidly along joints and bedding 
 planes, splitting up the rock into so many fantastic shapes, and how the 
 fragments that have been detached from the cliffs, by becoming lodged 
 among the ledges below, have been ground into rounded boulders, which 
 have thus eaten their way downward and scooped out for themselves 
 deep and wide cauldrons filled to the brim with clear green water, and 
 each a little world peopled with the plants and animals of the sea. 
 
 About half-way between the perforated cliff called the Needles Eye 
 and the deep creek knovni as Brotherston's Hole, a thin band of coarse 
 red sandy limestone occurs among the sandstones. It seems to die out 
 northwards, and its southern extension cannot be traced owing to the in- 
 tervention of a small fault. It is covered and underlaid by a few feet of 
 light grey sandy shale, with sphenopteris and other plants. From this 
 fault onward by Brotherston's Hole the sandstones again occupy the whole 
 cliff, their false-bedded strata weathering out as usual into picturesque 
 and varied outlines. At the bay of the Burgess Cove, however, an im- 
 portant dislocation takes place. It runs in a W.S.W. direction towards 
 the new Burial Ground, and its effi3ct is to bring in some of the lower 
 greenish sandy marls, sandstones, and bands of cement-stone, such as 
 occur near Burnmouth. These strata dip in a W.S.W. direction, un- 
 dulating at about 5° to 8°. After occupying the cliff and beach for 
 about 280 yards another fault runs in a parallel direction, with the effect 
 of bringing down some red and white sandstones. These are laid bare 
 on the beach, and also along the cliff, which has now greatly diminished 
 in height. 
 
 I believe that these sandstones, which run round the promontory of 
 Sharper Head, are the upper portion of the Burnmouth series, and that 
 the limestone which covers them is a prolongation of the limestone of 
 Lamberton. But in this I may be in error. Hardly have we tui-ned 
 southward round the Sharper Head than another fault runs across the 
 coast-line in a W.N.W. direction. On crossing it we find ourselves at 
 once among the Berwick limestones and shales. 
 
 It is from this point that the Carboniferous limestone group can be 
 consecutively traced up through the workable coals. But the descrip- 
 tion of these strata remains as the subject of a fiiture Memoir. 
 
 CHAPTER Vn. 
 
 Igneous Rocks later than Upper Old Red Sandstone and 
 Carboniferous Formations. Faults. 
 
 Reference has been made in Chapter V. to certain beds of ash and 
 greenstone, the date of which must be assigned either to the close of 
 the Old Red Sandstone or to the beginning of the Carboniferous period. 
 They are truly interbedded or contemporaneous volcanic rocks. But 
 associated witii both the formations just named, there are found in 
 Berwickshire a number of greenstone dykes and iosses of an intrusive 
 6802. D 
 
•is GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 cliaraoter, the date of which caunot be more nearly ascertained than 
 that they are in some cases later than the Mountain Limestone of this 
 district, later even than some of the dislocations by which the Mountain 
 Limestone is traversed. Although, for the sake of convenience in de- 
 scription, these intrusive rocks are here classed together, it is not m 
 any way assumed that they all belong to one geological period. On 
 the contrary^ it is quite possible that some of the dykes and masses in 
 the Upper Old Eed Sandstone may be of earlier date than the Car- 
 boniferous system. This seems by no means unlikely in such a case as 
 that of the great greenstone masses in the neighbourhood of Dunse. 
 We know that this locality was a focus of volcanic action at the close 
 of the Old Red Sandstone period, as shown by the ash of the White- 
 adder and of the Hardens Valley. Hence the basalts and greenstones 
 which now cap Dunse Law, Chapel Hill, and the long back of Borth- 
 wick HiU, may possibly have been ejected among the Old Eed Sandstone 
 strata before any part of the Carboniferous group had been laid down in 
 this part of the country. I shall notice first those igneous dykes and 
 bosses which occur only in the Upper Old Red Sandstone, next those 
 which traverse parts of the Carboniferous series. 
 
 At the lower left-hand corner of the Map a mass of greenstone is 
 shown on the west side of the pond in the park of Dunse Castle. This 
 is the eastern end of Borthwick HUl, which runs westward for nearly 
 a mile and a half. Dunse Law is capped with a similar hard black 
 basalt, though, owing to the amount of debris which obscures the sides 
 of this hUl, the exact area occupied by the basalt cannot at present be 
 determined. In the same neighbourhood a dyke of a remarkably red 
 ferruginous amygdaloidal greenstone occurs in the sandstone and con- 
 glomerate bands of Preston Haugh. It differs from the dark crystalline 
 greenstone of the Carboniferous rocks, and in this respect agrees with all 
 the other greenstone dykes which traverse the Upper Old Red Sand- 
 stone of the Lammermuir range. These wiU be described in the 
 Memoir to accompany Sheet No. 33. Not more than half a mile north 
 from Preston Haugh, a dyke of dark greenstone, weathering out into 
 concentric balls, traverses the granite in the bed of the Whiteadder, and 
 runs westward for nearly a mile and a half. The trend of this dyke is 
 W. 7° S. to E. Y° N., and it will be seen, on comparing the different 
 greenstone dykes on the Map, that this is the prevalent direction, irre- 
 spective altogether either of the formation or of the direction of the 
 beds traversed. 
 
 The dykes in the Carboniferous strata axe well exposed along the 
 coast between Lamberton and the Gull Rock beyond Burnmouth. At 
 the rooky promontory north of Hilton Bay, called Cateairn Bushes, a 
 dyke of greenstone may be seen running in the same W.S.W. direction 
 across the vertical sandstone. It ascends the cliff, adhering to one side 
 like a built wall, aad then actually crosses the great fault, without any 
 symptom of being disturbed by the passage. It is laid open in the 
 railway cutting, where it holds on its course across the contorted Silurian 
 strata with their associated felstones. On the shore at Burnmouth an 
 interesting dyke is visible. It cgnsists of a olayptone passing into basalt. 
 In the thinner parts of the dyke the rook is a dull granular claystone, 
 weathering with a pinkish grey colour ; where the dyke becomes thicker, 
 the central parts pass into a dull blueish sparingly amygdaloidal felspathic 
 basalt. Traced inland, this vein shows a very tortuous course. It dis- 
 appears in an irregular fissure not far from the N.E. corner of the pier, 
 but a similar rock takes its place in a parallel fissure which continues 
 to within a few yards from the pier, beyond which it ceases to be 
 traceable. The amount of alteration produced by the dyke is very 
 
FAULTS. i9 
 
 slight. The sandstones are in places a little hardened, but the shales 
 continue quite soft and unchanged up to the edges of this igneous rock. 
 
 In the glen of Burnmouth a dyke of basalt is seen rising as a wall 
 from near the base of the southern slope, about midway between the 
 top and the bottom of the ravine. Its course is a few degrees north of 
 west, and it traverses the Silurian strata, though possibly it may com- 
 municate underneath with the dyke among the Carboniferous beds on 
 the shore. 
 
 Less than half a mile further north, the beach is marked by a promi- 
 nent reef of black rock, rising as a broken ridge from among the 
 barnacled boulders that strew the shore. This is another dyke of basalt, 
 with the usual W.S.W. direction. It is in the central parts a hard blue 
 rock, in places strongly amygdaloidal, but towards the edges it is pale 
 and dull in texture. It varies in breadth from 20 to 30 feel;, running 
 across the highly inclined Carboniferous strata in a wavy serpentine 
 course, sometimes abruptly ceasing and then beginning anew. It does 
 not cross the fault, but is confined to the Carboniferous beds, which show 
 but little trace of alteration. 
 
 Another dyke of a crystalline greenstone may be ti-aced about a 
 quarter of a mile northward. It descends the cliff among the Silurian 
 grits and shales, and then runs seaward, cutting through two large 
 felstone beds. Whether it enters the Carboniferous series cannot be 
 ascertained, as the coast to the north of this point is entirely occupied 
 by the Silurian rocks. Similar dykes may be seen here and there along 
 the face of the steep cliff which now rises from the sea. One occurs 
 just below the patch of conglomerate which lies on the edge of the 
 precipice at Hawk's Heugh, but it does not reach the sea margin. 
 Again, at the Scout Cave a massive dyke of greenstone traversing the 
 Silurian rocks has at its seaward parts been excavated by the breakers 
 into a deep twilight cavern, the haunt of gulls and rock-pigeons. Some 
 smaller dykes of a similar greenstone may be observed intersecting the 
 grits and shales on the south side of the main mass. Though these 
 igneous intrusions are only seen here among Silurian rocks, I do uol 
 doubt that they are, like those of Burnmouth, later than at least the lower 
 members of the Carboniferous series. The same remark probably applies 
 to the greenstone dyke which has been referred to as having insinuated 
 itself among the felspathic and ashy rooks of Coldingham Shore, and to 
 a smaller one which cuts the ash on the cast side of Bell Hill. 
 
 Faults, —The three most important faults in this district radiate in a 
 southerly or south-westerly direction, from a point in the sea somewhere 
 to the east of St. Abb's Head. It is worthy of note that, in this 
 neighbourhood also, the focus of the Lower Old Red Sandstone 
 volcano appears to have existed. The largest of these faults is pro- 
 bably that which skirts the coast from Burnmouth to Berwick. Its 
 effect has been to depress the Carboniferous against the Silurian 
 series. At Burnmouth it is a low part of the former which is let 
 down next the line of dislocation, but owing to the curvature of that 
 lino, the lower members of the Carboniferous are gradually cut off 
 towards the south, so that the beds which abut against the Silurian 
 grits and shales at Lamberton form a portion of the base of the 
 Carboniferous Limestone. Another bend of the fault in the opposite 
 direction allows the lower members to come to the surface again, and 
 they are well shown on the banks of the Tweed below the western 
 outskirts of Berwick. The effects of this fault are prolonged into the 
 Scrcnierston Coal-field, where the strata along the coast are tilted up, 
 while those in the interior remain undisturbed. 
 
 The two other faults separate the Lower Old Eed Sandstone ashy 
 
50 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 beds from the Lower Silurian rocks. One has been ah-eady described 
 as probably running from Eyemouth in a S.S.W. direction, flanking 
 the high grounds of Lamberton Moor, until it is overlapped by the 
 red sandstones of Edingtonhill. Hence it would appear to be of older 
 date than the Upper Old Red Sandstone. The other skirts the north- 
 west side of the Silurian outlier of Coldingham Bay. It is impossible 
 to determine the extent of displacement produced by these fractures. 
 
 Three faults, two of which must be of considerable magnitude, 
 occur in the south-east corner of the Map. The two larger ones run 
 in a south-westerly direction nearly parallel to each other, and their 
 effect has been to let in a strip of the lower or Burnmouth beds among 
 the red sandstones at the bottom of the Carboniferous Limestone series. 
 Until accurate data can be obtained of the succession and thickness 
 of the various members of these lower parts of the Carboniferous 
 series in this district, it will not be practicable to offer any estimate 
 of the extent to which the faults in question have displaced the strata. 
 
 The third fault at this locality runs from W.N.W. to E.S.E., and 
 brings down some of the Berwick limestones against the red sandstones 
 at the base of this part of the formation. A good many others of 
 smaller size are seen on the shore between this point and Berwick 
 Pier. 
 
 No faults of consequence have been observed among the Silurian 
 districts. The strata there, as already explained, are violently con- 
 torted rather than actually fractured and displaced. 
 
 CHAPTER Vni. 
 
 Drift, Alluvium, Recent Marine Deposits. 
 
 The amount of denudation which the district now under discussion 
 underwent prior to the deposit of the boulder-clay, has been very 
 great. The Silurian rocks were probably tilted on end and worn down 
 to a great extent, before the volcanic ashes and conglomerates of the 
 Lower Old Red Sandstone were produced. Along with these later 
 formations, they were still further abraded previous to the laying down 
 of the Upper Old Red Sandstone and Carboniferous series, which are 
 largely made up of debris from the Lammermuir range. It is impossible 
 to estimate the amount of abrasion that went on during the vast interval, 
 here unrepresented, between the Carboniferous Limestone and the glacial 
 beds. Here and there a patch of old red conglomerate and sandstone 
 clinging to a hill-side reveals the fact that by far the greater part, if not 
 the whole of this district, was once covered with these deposits ; that 
 they stretched round the Lamberton Hills, across the valley of the Eye 
 Water, and away up among, if not over the valleys and hiUs of Lam- 
 mermuir. But before the deposit of the boulder-clay they had been 
 stripped off and left in a fragmentary state. How much of this de- 
 nudation is to be ascribed to the eroding agencies of the Drift Period, 
 it is now impossible to tell. Leaving this part of the question 
 unsolved, however, we can yet glean some interesting facts relative to 
 the form of the ground in some parts of the district, prior to and 
 during the deposition of the boulder- clay. 
 
 As the different Drift-deposits, to be immediately referred to, lie 
 chiefly in the hollows and valleys, it is plain that these depressions 
 must be at least as old as the glacial period. Indeed, it requires little 
 more than a cursory examination of the surface to assure us that 
 
DRIFT, &C. 51 
 
 the general contour of the ground, its hills and valleys, its declivities 
 and vs^atersheds, must have been on the whole the same during that 
 period as they are at present. The valleys have here and there been 
 widened and deepened, and some new ravines may have been eaten 
 out of the rock ; but such changes have been comparatively slight. 
 The framework of the county, so far as we can see, remains the same 
 now as it was when the older members of the Drift were deposited. 
 But as the most ancient of these deposits resulted from an enormous 
 abrasion of the surface of the land, it is quite possible that not a few 
 of the minor valleys of this district were produced at that time. The 
 abrasion, however, was so prolonged and stupendous, that most of the 
 distinctive features of the land-surface appear to have been effaced. 
 The soil, the vegetation, the lakes, the rivers, have been swept away, 
 and a mass of variously formed detritus has been left over their 
 former site.* Nevertheless, there are one or two localities in the 
 district where we seem to get a glimpse of some features of the land- 
 surface during, if not prior to, the earlier part of the Drift period. 
 Along the northern part of the coast-line between Cockburnspath and 
 St. Abb's Head, there are some deep and narrow ravines descending 
 from the high grounds to the sea. With the exception of some re- 
 markable defiles at St. Helen's Church, they are all occupied by tiny 
 rivulets : and their sinuous course, with the continuity of the strata 
 over which they run, proves that they are not mere rents or gaping 
 fissures, but that they have been gradually hollowed out by the power 
 of running water. Now, at the bottom of some of these ravines, in 
 little crannies which have been protected from the streams and runnels 
 that descend the steep banks on either side, there lie here and there 
 little nests of boulder-clay. These are not mere patches which have 
 been precipitated from the cliffs overhead by landslips, for we can see 
 sometimes the cross section where an old ravine is choked up with 
 boulder-clay, and the present rivulet is slowly clearing it out again. 
 Examples may be seen at the Menzie Cleuch, near the Eedheugh 
 Shore, in the deep defile of the Dulaw Dean, and in several other 
 water-courses along this coast-line. These channels are thus evidently 
 older than the boulder-clay which lies in them, and as they are mani- 
 festly the work of streams, they present us with traces of the water- 
 flow of the country during some part of the glacial period, if not prior 
 to that period altogether. There are no localities which promise better 
 to reward a diligent examination of the boulder-clay, than these 
 ancient water-courses. There, if anywhere, we may expect to meet 
 with traces of the plants and animals which inhabited Scotland during 
 the earlier part of the glacial period.f 
 
 But besides the ravines just referred to, which are plainly the work of 
 rivulets, there are certain other narrow glens, defiles, or channels (for 
 they vary not a little in size), in which there are either no streams or 
 runnels so tiny and local that they cannot be imagined capable of 
 
 * I may mention that traces of the old bed of the Whiteadder in glacial times, 
 ■with its gravels and clays lying under the boulder-clay, are to be seen on the bank 
 of the stream between Priestlaw and Cranshaws. The ancient glacial alluTium of the 
 Dye Water has also been partiaUy preserved under the boulder-clay, a short way 
 above the junction of that stream with the Whiteadder. Both these localities occur 
 in Sheet 33 of the Geological Survey. 
 
 t It is a remarkable fact that nearly all the mammalian remains and the vestiges 
 of terrestrial vegetation yet found in the Drift deposits of Scotland have occurred 
 along lines of valley. I have drawn attention to this fact in a paper on the Glacial 
 Drift of Scotland published in the Transactions of the Geological Society of Glasgow. 
 Part II. 1863. 
 
52 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 hollowing out by tlieir own unaesisted operations such marked excava- 
 tions as those in which they now flow. On the south side of St. Helen's 
 Church, for example, there is a deep winding ravine, quite dry, running 
 along the side of the declivity which here descends gently to the edge of 
 the sea-cliif. It is open at both its eastern and western extremity, thus 
 running across the neck of a promontory. With the present configura- 
 tion of the land, no stream could ever have flowed along this ravine. 
 Other but less-marked examples may be seen along the sea- front of the 
 hills eastward towards St. Abb's Head. Along with these features 
 ought probably to be classed those valleys which go right across the 
 watershed in diiferent parts of this district. Reference has been already 
 made to the valley traversed by the North British Railway as affording 
 a good illustration. Another occurs in one of the tributary valleys to 
 the west. The course of the little rivulet of the Pease Burn, when it 
 ascends to within a few yards of the flat watershed, turns sharply round 
 to the north-west, and follows the line of the ravine known as Edmond's 
 Dean. This is a narrow sinuous defile, excavated out of the hard 
 Silurian rocks. In ascending it, We at last cease to be accompanied by 
 the rivulet ; there is a flat meadow for a short distance, but the winding 
 sides of the deU run on as before, until when we again meet with rtuming 
 water, we see that it flows in the opposite direction, or towards the 
 north-west, descending by the farm of Ecclie to the Heriot Water. The 
 water then makes a detour round Ewieside HiU, and eventually i-eaches 
 the Pease Bum just below the bridge, and only about 500 yards from 
 the sea-shore. In such a case as this, it is conceivable that two streams 
 should have eaten their way backward until the neck of land or col 
 separating their water-courses was cut through, and the two united into 
 one ravine traversing the watershed. But over and above the power 
 of running water, and especially in such ravines as that of St. Helen's, 
 where no stream could have come into play, we must have recourse to 
 some other agency. The eroding power of ice, which is so marked in 
 the rounded and mammiUated contour of the ground, was in all likelihood 
 concerned in the hollowing out of these ravines, taking advantage, as it 
 would do, of any water-course or channel already existing, deepening, 
 widening, and extending it, and then leaving it to be subsequently 
 modified by the renewed activity of running water. 
 
 Dressed Rocks. — In what way soever we may explain the gulleys and 
 ravines just described, it requires little more than a casual survey to 
 assure us that the surface of this district, in common with that of the 
 i-est of Scotland, has been ground and shaven down by some agent of 
 enormous magnitude. The vertical strata of Silm'ian grits and shales 
 have their arches and edges as abruptly shorn off as the fibres and knots 
 of a piece of wood are smoothed down under a carpenter's plane. The 
 hills wear a rounded mammUlated look ; the valleys, in certain ti'acts, 
 particiflarly on the comparatively flat moory ground between the Eye 
 Water and St. Abb's Head, have a persistent trend in one direction, 
 which is from N.W. to S.E., even when they contain no running water 
 by which their outlines might have been modified. When the observer 
 places himself on some eminence commanding a view across the Coldingham 
 Moors, or on one of the craggy knolls in the vicinity of Dulaw, tiie fact 
 is vividly impressed upon him that the land ice, which has played so 
 important a part in moulding the present configuration of hill and valler 
 in this country, must here have come in immense force and thickncst^ 
 from the north-west, pressing steadily down the hollows, and taking 
 advantage of any inequality in the texture or surface of the rock eo as to 
 form new channels for itself along the line of its flow, thus smoothing off 
 
BOULDER CLAY. 53 
 
 the knoUa and crags, and communicating to the general surface that 
 rounded and flowing outline by which it is still characterized. 
 
 Although the surface of the country retains the fonn which was given 
 to it by the eroding power of the ice of the glacial period, the nature of 
 the rocks over most of the present district is such that the finer striations 
 by which the course of the icy stream was marked have gradually dis- 
 appeared except where protected by a covering of clay. They are still 
 visible, however, on some parts of the exposed front of the hills over- 
 looking the sea between Cockbumspath and St. Abb's Head. Their 
 direction corresponds with that of the valleys of the same neighbourhood, 
 i.e., from north-west to south-east.* I have not observed them elsewhere 
 in this district. 
 The superficial deposits of Berwickshire may be grouped as under ;— 
 Storm beaches. 
 
 River alluvium, peat and lacustrine marls. 
 Raised beaches ? 
 Drift r Sand and gravel ridges (Kamea), and briok-olays, 
 Series I. Boulder-clay or Till, resting on dressed rook-surfaces. 
 
 Boulder CZay.^This deposit presents here the features which usually 
 characterize it throughout the rest of the country. It is a stiff, sandy, 
 and gritty clay or earth, well charged with small gravel and stones, more 
 rarely, with large boulders. It bears a close conformity in colour and 
 composition with the rock on which it rests. Throughout the Silurian 
 tracts it is of a dull blueish-grey or pale fawn colour, and consists of 
 comminuted Silurian detritus. Eastward, where it lies on the red sand- 
 stone, it shows a bright red tint. It is always thoroughly unstratifled, 
 and so far as I have observed, it does not here contain any intercalations 
 of stratified materials. With the exception of the coast-line near 
 Cockbumspath, in no part of this district does any other deposit inter- 
 vene between the boulder-clay and the underlying rocks. Along the 
 shore, however, where the Pease Burn enters the sea, and also at intervals 
 for some distance towards the north-west, there occurs an irregular band 
 of shingle, frequently bound into a compact mass by cai'bonate of lime. 
 It rests usually upon the red sandstones of the cliff', sometimes upon a 
 sandy clay with scratched stones, and is covered by a similar clay, also 
 containing striated and polished stones. This intercalation of shingle 
 appears and disappears fitfully along the cliff-line. It contains large 
 round boulders and partings of sand, and is nearly as firm and compact as 
 any of the Old Eed conglomerates of the neighbourhood. 
 
 The best sections of boulder-clay in the area embraced in the present 
 map are in the ravines near Cockbumspath, and in the Ale Water about 
 a mile above its junction with the Eye. But the deposit may be examined 
 in some part of almost every water.course. Its absence, indeed, from any 
 part of the surface seems chiefly due to the effects of denudation. On 
 many of the hill-sides in the Silurian district we can trace the gradual 
 disappearance of the clay as it ascends the slopes. In the bottom of the 
 valley, it may be found lying in considerable thickness, and exposed along 
 the banks of a stream. Mounting the hill, however, we find that the 
 surface shows an increasing proportion of angular fragments of the 
 ordinary Silurian rocks of the neighbourhood, the more rounded stones of 
 the boidder-clay become correspondingly fewer, until we at last find the 
 solid rock protruding from the surface, and giving rise by its decom- 
 position to the angular detritus of the declivity. Yet even here we can 
 
 * Sir James Hall was the first to observe them here. My observations give 
 W. 35 N. as their line of bearing. 
 
54 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 detect, scattered over the sui-face, occasional rounded and even striated 
 stones, showing that the boulder-clay once stretched over the hills, from 
 which in the course of time it has been washed off. The clayey matrix 
 has been carried down to augment the alluvium of the valleys, and the 
 stones are thickly dispersed through the soil at the base of the hills. 
 
 Sand and Gravel Mounds and Ridges. Brick Clays. — Overlying 
 the boulder-clay in different parts of Berwickshire are masses of sand 
 and gravel, which occur sporadically, in patches sometimes of extremely 
 limited extent, and without any clearly definable relation to the form of 
 the ground. They lie sometimes along lines of valley, as in the defile 
 of the Pease Burn, sometimes across a valley, as on the north side of 
 Borthwick Hill, near Dunse, sometimes along the side of a hill or sloping 
 ground, as on the coast near Lamberton Toll, and sometimes in straggling 
 patches that run indiscriminately over hillock and valley, as round the 
 village of Cockburnspath. These deposits are usually well stratified 
 and fine in texture ; occasionally they pass into coarse shingle, where the 
 stratification becomes indistinct. Their general outline is that of low 
 mounds and lidges, but in some places they rise up steeply from the 
 boulder-clay surface on which they rest, and then look not unlike 
 artificial embankments or lines of rampart. The best illustration occurs 
 on the north of Borthwick Hill, where a ridge of coarse gravel and 
 sand crosses the road leading from Dunse Castle to Castle Mains and 
 stretches westward for about half a mile. Within a short distance of its 
 western extremity it crosses the valley obliquely, and is cut through by 
 the stream by which the valley is traversed. This is one of the most 
 prominent parts of its course ; a huge mound, or kame, like an artificial 
 rampart, has been laid down across the valley, and through this the stream 
 has cut a narrow passage for itself. Irregular heaps and hillocks of the 
 same materials are conspicuous between the turnpike-road and the edge 
 of the sea-cliffs at Lamberton Toll. The upper part of the ravine of the 
 Pease Burn shows a vast thickness of coarse shingle, and similar deposits 
 occur in the valley of the Eye Water at Houndwood, and along the high 
 grounds on the west side of the same stream, where it is joined by the 
 Ale Water. No organic remains have yet been detected in these 
 
 These masses of sand and gravel appear to a large extent to have resulted 
 from the washing away of the boulder-clay. We might expect therefore 
 that in some parts of the district, the finer argillaceous portions of the 
 boulder-clay ought to occur, filling up hollows of the older deposits, and 
 forming fields of brick-clay. There are almost no brick-works, however, 
 in this part of the country, nor do the streams lay open sections of these 
 finer clays. The only exposures which have occurred in the progress of 
 the Geological Survey are those in the brick and tile works at Linthill 
 on the banks of the Ale Water, and on either side of the Whiteadder at 
 Edrington Castle. At the latter locality a fine reddish clay with a few 
 striated stones scattered through it is worked. No organic remains were 
 observed in it. 
 
 Raised Beaches. — As the greater part of the coast-line rises from the 
 sea in a nearly vertical cliff averaging at least 200 feet in height, the 
 lines of raised beach which occur round the Scottish coast at levels of 
 25 and 40 feet above high-water mark are hardly to be looked for here. 
 The lower terrace, however, is famtly seen in some of the little inlets 
 that vary the outline of these wild shores. At Coldingham Bay, for 
 instance, and in that of Eyemouth, there ai-e tolerably level sandy flats, 
 from which the ground slopes up into the interior, and which may repre- 
 sent the lower raised beach. Nests of shells and sand are occasionally to 
 be seen among the crannies of the cliffs, 100 feet or more above the sea, 
 
LACUSTRINE MARLS. 55 
 
 but these have, in all probability, been swept up by storms. Some of the 
 sea-birds, also, carry littoral shells to their perch upon the cliffs. 
 
 Along some precipitous parts of the coast-line of Scotland, the ancient 
 level of the sea is marked by a line of caves, at a considerable height 
 above the present high-water mark. But in no part of the long line of 
 cliffs from Cockbumspath to Berwick have I detected any cave which 
 distinctly proves a rise of the land. The only instance of a cave above 
 the present sea-line occurs back from the edge of the cliffs between the 
 old church of Lambertou and the sea. There, along the sloping ground 
 that descends to the summit of the sea-cliff, a cave has been excavated, 
 apparently by the sea, out of the Carboniferous sandstones. It has 
 irregular, well- worn pillars and a steep roof, the floor being about 215 
 feet above the mean level of the tides. I could not trace any line of 
 erosion along the coast at the same level as that occupied by this cave. 
 
 Lacustrine Marls, Peat and River-Alluvium. — Several of the areas 
 now occupied by peat mosses appear to have been lakes at a former 
 period. An interesting illustration of this fact was obtained in October 
 1818, when the morass called Middlestot's Bog on the Kimmerghame 
 estate, in the parish of Edrom, was drained. Under the peat moss which 
 was seven feet thick lay a bed of sheU marl, varying in thickness from 
 four to eight feet. Immediately on the surface of the marl, and lying as 
 a thin partition between it and the peat, was a soft whitish layer of 
 various mosses, among which Sphagnum latifolium, S. capillifolium, and 
 Hypnum cuspidatum, could be readily distinguished. In this dividing 
 stratum, and extending partly into the marl below, the skeleton of a 
 beaver was found. Owing to the crumbling condition of the remains, 
 only the hard bones of the cranium and lower jaw could be removed 
 to Edinburgh, where they were deposited in the College Museum. 
 Dr. Neill, who described these interesting relics to the Wernerian 
 Society, remarked that on copaparing the fossil skulls obtained from 
 marl deposits in Scotland, with recent specimens from Hudson's Bay 
 and Canada, although they apparently all belonged to one species, the 
 former bore a much closer resemblance to each other than to any of the 
 four recent skulls with which they were compared. In the fossil speci- 
 mens, in particular, the nasal bones were observed to be proportionally 
 larger than the same parts in the recent ones. Several other heads of 
 the beaver were found about the same time at the same locality, but in 
 less perfect preservation. There was probably a beaver colony inhabiting 
 the Edrom lake before the water was gradually displaced by the accumu- 
 lation of peat.* 
 
 The progress of agriculture has done much to remove the wide 
 dreary expanses of peat which once covered so large a portion of Ber- 
 wickshire. In the north-eastern parts of the county, however, there 
 are still many morasses in the cold barren uplands of the Coldingham 
 Moors. Such are the Long Moss, Drone Moss, Dulaw Moss, Old 
 Cambus Moss, Bellstruther Bog, &c. Many of these appear at one time 
 to have been lakes ; but the only lake still surviving is that of Colding- 
 ham, near St. Abb's Head. 
 
 Alluvial deposits flank the margin of most of the larger streams, and 
 sometimes, as along the course of the Whiteadder, form broad flat 
 meadow lands, which are known as haughs. The best specimen in 
 the present district of this well-marked feature of Scottish scenery, lies 
 between the villages of Chirnside and Allanten, where the Whiteadder 
 
 * See Neill, Edin. Phil. Journ., i. 177 ; Mem. Wer. Soc, iii, 207 ; also Statistical 
 Account of Berwickshire, 1841, p. 267. 
 
 6802. E 
 
56 GEOLOGY OF EASTERN BKRWICKSHIEE. 
 
 and Blackadder waters commingle. A wide, long, and flat meadow, 
 traversed by the united streams, is bounded on either side, but more 
 markedly on the south, by steep banks, by which the edge of the allu- 
 vial plain is sharply defined. These banks are, for the most part, cut 
 out of the finely stratified Carboniferous shales and marls already' 
 described. It is deserving of notice, too, that even the minor streamlets 
 which descend into the Whiteadder have been able to cut for them- 
 selves channels of great depth and precipitousness, out of the same set 
 of yielding strata. This is remarkably exhibited by the streams in the 
 neighbourhood of Foulden and Edrington. The rapid alternation of 
 pale fawn-coloured strata, and the great depth to which these beds 
 have been excavated by even small streams, are appearances which 
 often resemble those of the volcanic districts of Central France, where 
 freshwater strata, not unlike in colour and banded stratification to these 
 Carboniferous shales of Berwickshire, have been similarly worn into 
 deep and wide valleys by the simple effects of running water. 
 
 Marine alluvium of recent origin is but of trifling extent in this 
 district, owing to the greater part of the coast-line being occupied by a 
 precipitous cliff. Banks of sand and shingle driven up by high tides 
 may be seen in some of the smaller creeks, as in the little cove of 
 Pettico Wick on the west side of St. Abb's Head. Almost the only 
 sandy beach along the whole coast is that of Coldingham Bay ; all the 
 rest of the sea-margin, with such trifling exceptions as Killiedraughts 
 Bay, is either strewed with coarse shingle and boulders worn from the 
 rocks above, or is formed by detached reefs, skerries, and sea-stacks, 
 among which the tides are ever breaking as they roll along these wild 
 iron-bound shores. 
 
APPENDIX. 
 
 LIST OP FOSSILS. 
 By J. W. Salter, A.L.S., F.G.S. 
 
 The following list comprises only those fossils which have teen collected by the 
 Geological Survey. For the sake of greater completeness, some of the fossils which 
 were obtained from places bordering the area represented on the accompanying map 
 are here included, but in each case the locality is given. It may also be mentioned 
 that the organic remains found in the Carboniferous beds indicated on the north- 
 western margin of this map are inserted in this list, although, as mentioned in the 
 foregoing pages, the description of these strata is reserved for the Memoir to accom- 
 pany Sheet 33 of the Geological Survey of Scotland. 
 
 LowEK SiLUKiAN (Caradoc). 
 
 GraptoUthus priodon - - ./ Siccar Point ; Old Cambus West Mains ; 
 
 L Jillemford, near Longformacus. 
 Tracks of Crustacea - - EUemford. 
 
 „ of Annelides - - Do. 
 
 Nemertites, wide species Siccar Point. 
 
 „ narrow species Do. 
 
 Old Red Sandstone. 
 Lcywer. 
 
 Linear grass-like plants, not leaves ofl ,, ,,, . , , 
 
 Sigilirm - - . . | Ale Water, near Ayton. 
 
 Pterygotus Anglicus, Ag. Anchencraw Bum. 
 
 Upper, 
 
 ■a ^ r Banks of Whiteadder, near Cockbum 
 
 Boots - - -| jjiii 
 
 n T 4. ■ r Do. do. (found here by 
 
 Cychpteris - -j Mr. Stevenson). 
 
 Annelide tubes - - Cockbum Mill. 
 
 Bothriolepis ornata. Ag. Harelaw quarry, near Chimside. 
 
 Cakboniebeous. 
 
 Calciferous Sandstones. 
 
 o ■ rrni. ■ ■ n„ f Banks of Whiteadder, one mile N.W. of 
 
 Sagenaria Veltheimmna, Gcepp - - -j diimside 
 
 n. 1 ^ ■ r Do. do. shore at Bum- 
 
 Cy'^^Pt^'-^^ - - -{ mouth. 
 
 Coniferous leaves (allied to SaUsburia ?) Hutton Mill, Banks of Whiteadder. 
 
 Sphenopteris - - - Cove, Cockbumspath. 
 
 Lepidophyllum - - Do. 
 
 ^ZfZ ^ui'^'Z"' T:J\- ^ "^"l Do.,atthebottomoftheCarboniferous 
 cadeous plant. (For description see >■ • 
 
 below) - - -J ^^™^- 
 
 Athi/ris amhigua - - Cove, Cockbumspath. 
 
 Modiola - - Do. 
 
 Pteronites - - Do. 
 
 Edmondia unionifmmis - - Do. 
 
 Sanguinolites - Do. 
 
 Aviculopecten - - Do. 
 
 Anthracomya. Sp. - Haven's Kuowe, Banks of Whiteadder. 
 
 Rldzodus Hibherti. Ag, Hutton Mill, Banks of Whiteadder. 
 
 „ Portloclii - - Raven's Knowe, Banks of Whiteadder. 
 
 Fish fragments - - - - Do. 
 
58 GEOLOGY OF EASTERN BERWICKSHIRE. 
 
 CAKBONirERons Limestone. 
 
 r Limestone No. 4, north from Berwick pier ; 
 Lithostrotlon junceum - -i Steps of Grace, three miles north of 
 
 L Berwick. 
 „ irregulare Steps of Grace. 
 
 „ Porilocki - Do. 
 
 Cyathophyllum Do. 
 
 _ , ,. r Limestone No. 4, north from Berwick 
 
 Zaphrentis - -| ^j^^.^ 
 
 Chonetes Hardrensis. Phill. Fisherman's Cove, Berwick. 
 
 „, „ , , r Shale under Limestone No. 2, north from 
 
 Wiyncmdlapkuroden - - -| Berwick pier. 
 
 Productus semireticulatus, var. eoncinnus Do. 
 
 r Limestone No. 4, north from Berwick 
 ,, ., giganteus | ^j^^. 
 
 „ ^ , . , . ,. , . r Shale under Limestone No. 2, north from 
 
 Streptorhyncuscremstna, var. cyanancum -i nprwjck nier 
 
 Lingula squamiformis - Do. 
 
 Spirifer bisuhatus . . - Steps of Grace. 
 
 Edmaadia unioniformis - Bhale under No. 2 Limestone. 
 
 „ „ , , ^ r Fisherman's Cove, and in shale under 
 
 Bellerophon decussatus -j No. 2 Limestone. 
 
 Desceiption oe New Cycadeotis Plant. 
 Cycadites Ccdedonicus, nov. spec. 
 
 Ctcadites Caledokicus, n. sp. 
 
 C. Folia modica semipedaJia, rhachide incurvo crasso, suhtus valde convexo, supra 
 angustato, pinnis crebris approximatis, fere unciam longis, liuearibus, angnstis (iiix ^ 
 linece latis) obliguis, ad basin paullulum tortis, contractis. 
 
 The specimen here noticed was found in a hard micaceous sandstone at the base of 
 the Carboniferous rocks, or rather at the base of that portion of them which 
 immediately overlies the red and yellow sandstones of Berwickshire. It occurs at 
 Cockburnspath a few miles S.E. of Dunbar, and in beds which contain a large Sigillaria, 
 Zepidrodendron, &sh deiences(_Gyracanthus'), and a few Carboniferous shells. They 
 are the very lowest members of the Carboniferous system in Scotland. The sandstone 
 beds in question are of about the age of the building stones of Edinburgh and Leith • 
 and lie far below the true mountain limestone ; in some places 2,000 and even 3,000 
 feet, below the actual limestone beds. These details are given in order to show that the 
 rock in question is much older than the ordinary Coal Measures, and therefore that 
 Cycadeae are very ancient fossils. 
 
 The frond measures 4 inches in length, and consists of a rhachis, 1 line thick, and 
 very convex beneath, and narrow above, on the plane, curved upwards towards the 
 plane from which the pinnae start. These are closely set, not above ^ of an inch 
 apart at their base, which is contracted immediately after the insertion, and somewhat 
 twisted so as to present the blade of the pinnae obliquely forward. Pinnse very 
 numerous, narrow linear, gently curved forwards, about § of a line broad, nearly 
 three-quarters of an inch long, and slightly concave. The foregoing diagnosis compre- 
 hends all that can be made out from the specimen, which in many parts retains the 
 carbonaceous matter of the plant itself. The apices of the pinna: cannot be seen, being 
 imbedded in the coarse grit. 
 
 There is certainly one cycadeous plant if not more, in the tine coal, viz., the 
 Pterophyllum irifiexum, figured by Eichwald on his Lethsea Rossica, from the coal 
 measures of the Altai mountains. But I do not know that any have been described 
 oefore from strata so low as the base of the Carboniferous system. 
 
 LONDON: 
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 Printers to the Queen's most Excellent Majesty. ' 
 [9482.— 500.— 11/63.] 
 
LIST OF GEOLOGICAL MAPS AND SECTIONS OF THE GEOLOGICAL SURVEY 
 
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 57 SW. Part of Cardiganshire. ,. ^ 
 
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 59 NW. Sea. ^ ^ 1,, ■ .^ 
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 60 NW. Part of Montgomerj- and Merioneth. 
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 60 SE. Part of Montgomery, Radnor, and Shropshire. 
 
 61 NW. Part of Shropshire. , „^ „ ... 
 61 NE. Part of Shropshire and Staffordshire. 
 61 SW. Part of Shropshhe. 
 
 61 SE. Part of Shropshire. 
 *62 NE. Lichfield, part of Staffordshire. 
 *62 SE. Birmingham, part of Warwickshire. 
 •62 SW. Partof Staffordshire, including the Coalfield. 
 •62 NW. Part of Staft'ordshire, including the Coalfield. 
 •63 NW. A.shby-de-la-Zoueh, part of Leicestershire. 
 
 63 NE. Leicester. , , , ,„ . , , . 
 
 *63 SW. Hinckley, part of Leicestershire and Warwickshire. 
 *63 SE. PartofLeicester, Warwick, and Northamptonshire. 
 •71 NE. Nottingham. 
 
 71 NW. Nottingham, part of Derbyshire, 
 ♦n SW. Derby. 
 
 71 SE. Part of Nottinghamshire. 
 
 72 NW. Hanley. Part of Staffordshire. 
 
 72 NE. Part of North Staffordshire and of SW. Derbyshire. 
 
 72 SW. Central Part of Staffordshire. 
 
 •72 SE. Part of Staffordshire and SW. Derbyshire. 
 *73 NW. Part of Cheshire. 
 
 73 SW. Part of Shropshire. 
 
 73 SE. Part of Shropshire and Staffordshire. 
 
 73 NE. Crowe. 
 
 74 NW. Part of Denbigh, Merioneth, and Caernarvon. 
 
 74 NE. Part of Denbign, FUnt, Shropshire, and Merioneth. 
 74 SW. Partof Montgomery, Denbigh, and Merioneth. 
 
 74 SE. Partof Shropshire, Montgomery,andDenbigh. 
 
 75 N W, Part of Caernarvon. 
 
 75 NE. Part of Caernarvon, Merioneth, and Denbigh. 
 75 SW. Part of Caernarvon. 
 
 75 SE. Part of Merioneth. 
 
 76 N . Part of Caernarvon. 
 
 76 S. Part of Caernarvon. 
 
 77 N. Part of Holyhead Island. 
 
 78 N W. N. part of Anglesea, and part of Holyhead Island. 
 78 NE. B. corner of Anglesea. 
 
 78 SW. S. of Holyhead Island and of Anglesea. 
 
 78 SE. Part of Anglesea on Menai Straits. 
 
 79 NW. Part of FUnt, Denbigh, and Caernarvon. 
 79 NE. Part of Flint, Cheshire, and Lancashire. 
 
 79 SW. Part of Flint, Caernarvon, and Denbighshire. 
 
 79 SE. Part of Cheshire, Flint, and Denbigh. 
 •80 NE. Altrincham. 
 
 80 SE. Northwich. 
 
 80 SW. Chester, part of Cheshire. 
 
 *80 NW. Part of Cheshu-e and Lancashire. 
 
 •81 NE. Partof Derbyshire and of W.R. Yorkshire. 
 
 81 SE. Part of Derbyshire and of N. Staffordshire. 
 •82 NE. AVorksop. 
 
 82 NW. Chesterfield, part of Derbyshire. 
 •82 SE. Mansfield, 
 
 82 SW. Chesterfield, part of Derbyshire. 
 87 NE. Snaith. 
 
 87 SE. Doncaster. 
 
 88 SW. Oldham and Manchester. 
 •89 SW. Wigan. 
 
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 These Sections are drawn to a scale of six inches to a mile, horizontally and vertically, and describe in detailthe Geolcpr 
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 VBBTICAIi SBCTIOWS, 
 
 npustrative of the Horizontal Sections and Maps of the Geological Survey. 
 
 ITiese Sections are arranged, in the form of Vertical Columns, to a scale of 40 ft. to an inch, and illustrate such details as ■ 
 
 it is impossible to give in the Horizontal Sections above described. In the Coal Measure Sections, for instance, the Thickness 
 
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 memoirs of the C^eological Survey and of tbe BSuseum of Practical Ceologry. 
 
 EEPORT on COENTVALL, DEVON, and WEST SOMEESBT. By Sir H. T. De La Beode, P.E.8., &o. 8vo. 14s. 
 riGITEES and DBSCEIPTIONS of the PALiEOZOIC FOSSILS in the above Counties. By PnoFESSOB Phiilips, F.E.8 
 
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 CATALOGUE OF THE CONSENTS OF THE MINING RECORD OFFICE. Price ad. 
 
 MINEEAL STATISTICS for 1853-1854,1855,1856,1367, 1858, 1859. embracing the produce of Tin, Copper, Lead, Silver, Iron,: 
 
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 the One-inch Scale, and Sheets 84, 86, 92, 93, 100, 101 on the Six-inch Scale, iancashire, (2nd Edition )]Mce Is 
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 COUNTEY around ALTEINCHAM, CHESHIRE. Illustrating 80 N.E. Price Sd. 
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