rk. Ms ww California Academy of Sciences RECEIVED BY PURCHASE a ea . ds | eee ae is Mahe ee yy te , ue. i at f ‘un y } . Digitized by the Internet Archive = in 2011 with funding from California Academy of Sciences Lib’ oes os ’ naeal, go ba to a . " | ae, http://www.archive.org/details/transactionsofge41 geol . [ ' * mi . a a TRANSACTIONS OF THE GEOLOGICAL SOCIETY, ESTABLISHED NOVEMBER 13, 1807. VOLUME THE FOURTH. Quod si cui mortalium cordi et cure sit, non tantum inventis herere, atque iis uti, sed ad ulteriora penetrare; atque non disputando adversarium, sed opere naturam vincere ; denique non belle et probabiliter opinari, sed certo et ostensive scire; tales, tanquam veri scientarum filii, nobis (si videbitur) se adjungant. . Novum Organum, Prefatio. avs LONDON: PRINTED AND SOLD BY WILLIAN PHILLIPS, GEORGE YARD, LOMBARD STREET. ; 1817. F ; es eh ae ‘ a ; a t a) . u ‘ i" . ; “ ‘i ae > enOtto Revi ap F "7 . tee 4 ; r ‘ : pry Oy hed. ey 9 ef Ra 9 P . / ats f i 4 ae -. . ua ee RRR ae OT 4 . Pat ? i rhe ; Vir . J "Oh ‘ Wi : nm ty ar | k ¥ a ae ae as ae y te ee Be i “a a # * hse 8 OG We, of " a fo. ee ae ak, al Re wy -* a ie 7 \ . s t 4 . ’ * gu ~ ae | hf ¥ f a iv) ae Shot er ee Ee hn —- = 4 it he rn ” om a! t ce { ‘ i 1 , “ bs = , 1 5 i 4 my, nase 1 py Hie) eutyee aod (Hasta. faite. iy RYE, Siieas, Seed 'y lt , f ; : ay on eo: eae ; es dis anieyia tt “peael! Vela are) ee ri wea TE RINE AVI Soe fy * ’ * : ‘ ' : Ngo iz L ore i ‘ Spelrhing Ht ae GN Ais spi iF ee ; ‘ail . F A ‘ 4 . 3 ue i i ty ST F re f , “a ai enal'’ ene) WG. Wl ie rte ive ae y \ 5 = vey i ¥ L “ SH : ‘ fey? | S ‘ é . 5 - 1 f = m A bit * a y ‘ - ; os a ihr " wer . { . w , us 4 : 4 ar ake ‘ . a : ¥ * ~ ‘ ; ’ ae OFFICERS AND COUNCIL OF THE GEOLOGICAL SOCIETY, ELECTED FEBRUARY 7, 1817. PRESIDENT; JOHN MAC CULLOCH, M.D. F.L.S. VICE-PRESIDENTS, The Hon, HENRY GREY BENNET, M.P. F.R.S, | The Right Hon. Sir JOHN NICHOLL, MP. F.R.S. WILLIAM BLAKE, Esq. F.R.S. HENRY WARBURTON, Esq. F.R.S. , SECRETARIES, CHARLES STOKES, Esq. FA.& LS. | HENRY JAMES BROORE, Esq. FOREIGN SECRETARY, AUGUSTUS BOZZI GRANVILLE, M.D. F.L.S. © TREASURERS, DANIEL MOORE, Esq. F.R.A. & L.S. | JOHN TAYLOR, Esq. COUNCIL, ARTHUR AIKIN, Esq. HENRY HOLLAND, M.D. ERS. THOMAS COLBY, Esq, Captain of the Royal ASHHURST MAJENDIE, Esq. Engineers. # WILLIAM HASLEDINE PEPYS, Esq. F.R.S. HENRY THOMAS COLEBROOKE, Esq. F.R.S. EDMOND WALLER RUNDELL, Esq. Sir HENRY CHARLES ENGLEFIELD, Bart. F.R A. & R.S. Ed. & A.P. Newc. M.R. Inst. SAMUEL SOLLY, Esq. F.R.S. GEORGE BELLAS GREENOUGH, Esq. F JOHN WHISHAW, Esq. F.R.S. - F.R. & LS, WILLIAM HYDE WOLLASTON, M.D. E.R.S. KEEPER OF THE MUSEUM AND DRAUGHTSMAN, Mr. THOMAS WEBSTER, TRUSTEES OF THE GEOLOGICAL SOCIETY, GEORGE BELLAS GREENOUGH, Esq. Sir ABRAHAM HUME, Bart. M.P. WILLIAM BABINGTON, M.D. ROBERT FERGUSON, Esq. DAVID RICARDO, Esq. SAMUEL WOODS, Esq. ADVERTISEMENT. THE Ediiors of the Transactions of the Geological Society are directed to make it known to the Public, that the Authors alone are responsible for the facts and opinions contained in their respective papers. Geological Socicty, July 1, 1817. It is requested that all letlers and communications to the Secretaries, and presents to the Society, be addressed to the House of the Geological Society, No. 20, Bedford Street, Covent Garden, London. Page 4 line 21 for ib. —— 23 —— 14 —— 24 —— 17 —- 5 ib, —— 14 after 20 —— il for 28 —— 15 67 —— 8 —— 74 -—— 22 —— 106 —— 3 —— 108 lastline —— 109 line 2 —— 110 5 of note — 126 —— 25 —— —— 26 before 230 —— 16 for 290 —— 14 —— 304 —— 14 before $11 Jastline (for 312 line 15 405 (2nd column 406 hei figures ng AQ7 (the sections ERRATA. AQO rechten RON ee otha read 530 Whitby > jo csescte Whitley north. . /steaiateveteietss south “4 Thil-whin’ss2. ose Thil Jameson saree insert ? Lbs wee ere a tee ee read is Paling: 's seis as Felling 1 toda —— 3miles west of Newcastle SONATE Ss cin ceis tee Temming. Hesket, Newmarket —— Hesket-newmarket water course at &c. water course. At of Melmerby. The —— of Melmerby the COUTSE LON aes wie — coarse ETAVETSES!etete oa oloic-bile traverse Often. coven ae insert is MVE nei so creciels be ote read \evel OL tae sat sean elena ees —— at shames’. cyetateracitee insert the ascendd the istance read ascend the distance numulites........ nummulites INCHES 3.4)s aaleienares feet If. III. PV. VI. CONTENTS. PART I. Observations on the Geology of Northumberland and Durham. By N. J. Winch, Esq. F.L.S. Honorary Member of the Geological Society - - - - - - - p. 1 On a Whin Dyke traversing Limestone in the County of Northum- berland. By the Hon. Henry Grey Bennet, M.P. F.R.S. Vice- President of the Geological Society - - - - p. 102 Description of an insulated Group of Rocks of Slate and Greenstone, in Cumberland and Westmoreland on the east side of Appleby between Melmerby and Murton. By the Rev. William Buckland, B.D. Professor of Mineralogy in the University of Oxford, and Member of the Geological Society — - - - - p. 105 PART II. Observations on the Mountain Cruachan in Argyleshire ; with some Remarks on the surrounding Country. By John Mac Culloch, M.D. F.L.S. President of the Geological Society, Chemist to the Ordnance, Lecturer on Chemistry at the Royal Military Academy, and Geologist to the Trigonometrical Survey - Sen ag es Account of some remarkable Disturbances in the Veins of the Mine called Huel Peever, in Cornwall. By John Williams, Esq. Honorary Member of the Geological Society - - -p. 139 Description of the Tunnel of the Tavistock Canal, through Morwel Down, in the County of Devon. By John Taylor, Esq. Treasurer of the Geological Society - - - - - p. 146 b CONTENTS. VII. Corrections and Additions to the Sketch of the Mineralogy of Sky, published in the Third Volume of the Transactions of the Geological Society. By John Mac Culloch, M. iD dara S. ORE a the Geological Society, &c. &c. - p. 156 VIII. On the Strata in the Neighbourhood of Bristol. By Richard Bright, M.D. Member of the Geological Society. With Notes, extracted from the Communications of George Cumberland, Esq. Honorary Member of the Geological Society - - - - p. 193 Note on Magnesian Breccia. By Henry a Ene. Vice- President of the Geological Society ~ - p. 205 IX. On the Magnesian Limestone and Red Marle or Sandstone of the Neighbourhood of Bristol. By W.H. Gilby, M.D. - p. 210 X. On the Strata at Whorlbury Camp, in Somersetshire. By George Cumberland, Esq. Honorary Member of the Geological Society pp. 216 XI. Observations on the Hill of Kinnoul, in Perthshire. By John Mac Culloch, M.D. F.L.S. Biesident of the Geological Society, &c. &e. - - - - . - - p. 220 XII. Account of some attempts to ascertain the angles of the Primitive Crystals of Quartz and of the Sulphate of Barytes, by means of the reflecting Goniometer, together with practical reasons for presuming that the admeasurements assigned by Hauy to several varieties of the parallelopiped and of the octohedron are inaccurate. By William ~ Phillips, Member of the Geological Suciety - = 2 = pede XIII. On the Measurement, by the reflecting Goniometer, of certain primi- tive Crystals ; with Observations on the methods of obtaining them by mechanical division along the natural joints of Crystals. By William Phillips, Member of the Geological Society - p. 241 XIV. Supplementary Observations on Quartz Rock, made in 1814. By John Mac Culloch, M.D. F.Z.S. ‘Penton of the Geological Society, &c. &c. - - - - - - p. 264 XV. Description of a series of Specimens from the Plastic Clay near Reading, Berks. With Observations on the Formation to which those Beds belong. By the Rev. William Buckland, B.D. Member of the. Geological Society, and sister of Mineralogy in the University of Oxford - - - 2.) p. 277 CONTENTS. XVI. On some Beds of Shell Marle in Scotland. By Henry Warburton, Esq. F.R.S. Vice-President of the Geological Society - . p. 305 XVII. Geological Remarks on the Vicinity of Maestricht. By the Rev. W.E. Hony, Fellow of Exeter Shee i ahs Member of the Geological Society - - - - p-310 XVIII. On the Parallel Roads of Glen Roy. By John Mac Culloch, M.D. FLL.S. President of the Geological Society, &c. &c. - p- 514 XIX. On a Shifted Vein occurring in Limestone. By John Mac Culloch, M.D. F.L.S. President of the Geological Society, &c. &c. - p. 393 XX. Luxplanation of a Supplementary Plate to the Paper on Vegetable Remains preserved in Chalcedony, printed in the Second Volume of the Transactions of the Geological Society. By John Mac Culloch, M.D. F.L.S. President of the Geological Society, &c. &c, = p. 3 XXI. On a peculiar Disposition of the Colouring Matters in a Schistose Rock. By John Mac Culloch, M.D. F.L.S. President of the Geological Society, &c. &e. - - - - - p.399 XXII. Memoranda relative to the Porphyritic Veins, &c. of St. Agnes in Cornwall, By the Rev, J.J. Conybeare, Member of the Geological Society - . - - - - - -p. 401 XXIII. On the Stream Works of Pentowan. By Edward Smith, Esq. p. 404 XXIV. Observations respecting the Limestone of Plymouth, extracted from two Letters, dated September 26, 1814, and January 19, 1815, addressed to Henry Warburton, Esq. Secretary. By the Rev. Richard Hennah, junr. Chaplain to the Forces at Plymouth p. 410 XXV. Description of the Paramoudra, a singular fossil body that is found in the Chalk of the North of Ireland ; with some general Obser- vations upon Flints in Chalk, tending to illustrate the History of their kormation. By the Rev. William Buckland, B.D. Member of the Geological Society, and iad of Mineralogy in the University of Oxford - - - p.413 XXXVI. Notice of Fossil Shells in the Slate of Tintagel. By the Rev. J. J. Conybeare, Member of the Geological Society - p. 424 XX VII. Notice of some peculiarities observed in the Gravel of Litchfield. By Arthur Aikin, Esq. Member of the Geological Society, and Secretary to the Society for the Encouragement of Arts, Manu- Sactures, and Commerce - - - . - p. 426 CONTENTS. XXVIII. Analysis of one hundred parts of a dark Bituminous Limestone, from the Parish of Whiteford, in Flintshire, Vth Wales. By Edward Daniel Clarke, LL.D. Professor of Mineralogy in the University of Cambridge, and Honorary Member of the Geological Society - - - - - - - p. 430 X XIX. Barometrical Measurements. By William Allen, Esg. F.R.S. and Samuel Woods, Esq. Members of the Geological Society - p. 434 XXX. Notice concerning the Shropshire Witherite. By Arthur Aikin, Esq. Member of the Geological Society, and Secretary to the Society Jor the Encouragement of Arts, Manufactures and Commerce p- 438 XX XI. Extracts from the Minute Book of the Geological Society - vp. 443 List of Donations - - - - - - - p. 451 Index = = - - = - * - p.459 I. Observations on the Geology of Northumberland and Durham. By N. J. WINCH, Esq. HONORARY MEMBER OF THE GEOLOGICAL SOCIETY, Read March 18th, 1814.* CoNSIDERING the great importance of the coal and lead mines, and of the quarries of Northumberland and Durham, and the oppor- tunities which they offer to geological research, it is rather singular that no history of the physical structure of these counties has yet been laid before the public. It is however well known that much interesting information on these subjects has long been accumulating and is widely diffused among the professional conductors of the mines. I have endeavoured in the following paper to combine some of these scattered materials with the substance of my own observations, and to give a general outline of the several formations that compose our district. I have added short descriptions of the principal rocky strata belonging to these formations, and catalogues of such of their metallic ores, crystallized minerals, and organic re- mains, as have come under my notice. _* This paper was read at the meetings of the Society six months before the publication of the sketch of the same district by Dr, Thomson. See Annals of Philosophy, for November and December, 1814. VOL. 1¥. A “ Mr. N. J. Wincu on the Geology of I. Red Marl or Sandstone. In the south-eastern part of the county of Durham a series of strata occurs, among which a fine grained sandstone of a brick-rell colour, effervescing with acids, predominates. This rock may be seen in the bed of the Tees at the distance of more than a mile west of Croft bridge; thence it follows the course of the river to the sea, and may be traced at some little distance from its northern bank through Hurworth, Nesham, Sockburn, &c. beyond the town of Stockton, forming rocks on the sea shore between Seaton and Hartle- pool. Opposite Sockburn, Mr. Allen of Grange, lately bored in search of coal to the depth of 118 fathoms, without passing through these beds; and at Dinsdale, situated on the northern bank of the Tees, three miles and a half north-east of Croft bridge, in. the year 1789, the late General Lambton. penetrated to the depth of 74 fathoms without better success. I have obtained five sections of the workings at Dinsdale, and have communicated them, together with the present paper, to the Society. The strata are numerous, and consist (as far as one can judge from the miner’s language) of white, grey,, or red sandstone with occasional partings of a more compact nature,, red or blue shale, coaly matter in thin layers, and gypsum in nodules, or in beds; the latter are mentioned in one case as. being three feet: in thickness. ‘The lowest bed in the two deepest workings was: a: strong white rock of a calcareous nature. I should not have inserted these rude sections in the appendix (No. 1), to this paper had it not been for an opinion prevailing in Yorkshire, that coal will be found among these measures, and I hope by the. publication of this document: to prevent. the future waste of capital: on similar trials. Northumberland and Durham. 3 ’ From one of these bore-holes, at a place called Woodhead, near the Tees, a sulphuretted water issued, similar to the Harrowgate spa.* It arose from a bed of blue stone lying beneath a bed of gypsum at the depth of nineteen fathoms two feet six inches from the surface. Another sulphuretted spring rises from similar strata at Croft on the south side of the Tees, where baths have been erected for medical purposes. ) There can be little doubt that the sandstone we have been de- scribing is analogous to that extensive formation of the same sub- stance and colour which is found in Nottinghamshire to the west of the magnesian limestone, and it probably may be traced in continuity from the banks of the Tees through Yorkshire into the neighbour- ing county. Il. Magnesian Limestone. _ To the north-west of the red sandstone the Magnesian’ or Sunder- land limestone is found. In the cliffs at Cullercoats in Northumber- land, a dyke well known by the name of the xinety fathom dyke, is seen dislocating the coal-measures, and passing into the sea. Here” is the northern extremity of the western boundary of the magnesian limestone. A few masses again occur among the rocks of sandstone and slate-clay, upon which Tynemouth castle stands; but it is on _* Mr. Peacock of Darlington published the following analysis of this water. in a pamphlet on the medical virtues of the spring. Contents in 1 quart. . Carbonate of Lime .......... 0200000 c eee eees ..Grains 1.2 SEU DHGE. Of CAINE Vets, asin. uis aot a eSruoems sonery Sasha ouad ord 25. Camiguin Mal Gags, cee ede e ree cee Sulphuretted Hydrogene, containing 24 eae of Silphur. 8.32 Azotic: Gags. sescn fhe «ete h} 19. sidai@h..OEeh... eG rains ts Specific gravity of the water 1.016. Temperature at the well 8° above that of the adjoin- ing springs. AQ 4 Mr. NJ. Wincn on the Geolory of the coast in the neighbourhood. of South Shields in the county of Durham that this formation first becomes extensive. From this point it swells into a range of low round-topped hills, and.is seen stretching towards the south-west, protruding into the Coal-field, and forming an undulating line by Cleadon, Boldon, Clacks Heugh upon the Wear near Hilton castle, Painshaw, Houghton-le-Spring, Sherburn, Coxhoe, Ferry hill on the turnpike road leading from Durham to Darlington, Merrington, Eldon, Brussleton, Morton, Langton, and Sellaby, till it reaches the Tees below Winston bridge thirty miles west-south-west of that river’s junction with the sea, and forty-four miles from the Tyne at South Shields. The sea coast ferms its eastern boundary for twenty-seven miles and a half from © the Tyne to the rocks of Hartlepool, and the red sandstone already mentioned from Hartlepool to the termination of that rock west of Croft bridge. The same bed is afterwards continued through Yorkshire, Derby- shire and Nottinghamshire, to the neighbourhood of Nottingham, where it suddenly terminates. | Of the hills of this rock, protruded into the Coal-field, Painshaw near Lambton appears to be the highest, being probably not less than 400 feet above the level of the sea. Kirk Merrington, situated on one of these hills may also be seen to a considerable distance. . The quarry at Whitby near Cullercoats affords the geologist an excellent opportunity of ascertaining that the magnesian limestone overlies the coal-measures, and that the latter were consolidated before the limestone. was. deposited upon them. I shall therefore describe that curious spot. — A hollow space formed like a basin or trough is filled with the limestone.*. ‘The length of this from east to west is about a mile ; * Plate 4, fig. I, Northumberland and Durham. 5 the breadth from north to south four hundred yards, the depth seventy feet. The beds pass over the ninety-fathom-dyke ; which has oc- casioned in them no confusion or dislocation ; so that there can be little hazard in stating that the beds of the magnesian limestone belong to a more recent formation than those of the Coal-field. The limestone has been quarried across its whole breadth, and a nume- rous set of thin strata are thus exhibited to view. At the surface loose blocks of bluish grey coralloid limestone, the produce of the lead mine district are found imbedded in the soil. Three or four of the uppermost strata of the quarry are of white slaty limestone, which being nearly free from iron, burns into a pure white lime. Below these an ash-grey fine grained stratum is met with, which strongly resembles a sandstone, and seems to contain nearly as much iron as the ferri-calcite of Kirwan, becoming magnetic by the action of the blow-pipe: it produces a brownish yellow lime, less esteemed for agricultural purposes than the former. The beds next in succession are of an ash-grey colour, are compact in texture, and conchoidal in fracture: these afford a buff coloured lime, which sells for nearly the same price as the white. Near the bottom.of the quarry the limestone alternates with shale ; the whole rests upon a stratum of shale on the southern side, and upon a thick bed of sandstone on the northern. ‘The shale has been cut through to a considerable distance from the kilns in the direction of North Shields, for the purpose of laying a rail-way to the Tyne. The thickness of the limestone strata varies from three or four inches to as many feet. Small strings of galena have been found here, and, in one of the strata that was walled up when I visited the quarry, a few organic remains have been noticed. The stone intended to be burnt is detached from the rock by the agency of fire, during which process those portions which contain 6 Mr. N. J. Wincu on the Geology of iron become of a brick-red colour. Considerable quantities of fuel are found necessary at the kiln, and some parts of the rock are too apt to vitrify in the process, an accident to which the crystalline limestone of Sunderland is not liable. Along the coast of Durham from Shields to Hartlepool, the uppermost bed frequently consists of a species of breccia, the cement of which is a marl-like substance consisting chiefly of magnesian carbonate of lime, and with this breccia wide chasms or interrup- tions in the cliff are filled. The next strata are thin and slaty, but lower down the stratification becomes less distinct. The colour of this rock is then light hair brown, the texture crystalline and cellular, from which latter cause it strongly resists the stroke of the hammer. The slaty variety occurs at Bolden hills, Marsden rocks, and numerous other places; its colour is white inclining to buff; dendritical marks may be found between the thin layers into which it easily breaks ; and in Marsden lane and on the sea coast a flexible kind has lately been noticed by Mr. Nichol. In the neighbour- hood of Sunderland* the brown variety is generally quarried ; it partakes of the nature of swinestone, and from containing some inflammable matter requires only a small quantity of coal to be reduced to lime. That worked at Denton, not far from the Tees, and analyzed by the Rev. J. Holme, is, I suspect, of this quality, for he mentions bitumen, as one of its constituents; whereas Sir H. Davy takes no notice of that substance in the rocks of Eldon and Aycliff. ( * The exportation of lime from Sunderland is chiefly to Scotland, and amounts to from forty-two to forty-five thousand chaldrong of 36 bushels each, annually. fe Northumberland and Durham. 4 Analysis of 100 parts of Limestone. By the Rev. J. Holme. By Sir H. Davy. From Denton. From Eldon. From Aycliff, pCarhonate'of Lime) .r. 0/5. rei." F sof GS Sie . sherk.td + « DBT aactd totes 48.9 of Magnesia’ 5... js: crite oat SA le Sh ey Atr nis joisbe AES Dei eg alc, sleka 46.6 “Alumina, Red Oxide ofTrom,)” ©" 9.95 | Tron ..+..:2. SM letciten as 1.66 and Bitumen. DAW DEET? . Foy Site c.0. Maresh plates oct EDN > FOG os ed, | Bs cp ttcre'e 0 6 2.8 100. In a quarry at Hartlepool I have noticed a stratum of hard white eolite, the grains composing it being about the size of a mustard’ seed; but, unlike the Ketton and Riflington roe-stones, it: contains no shells or marine exuvie. TI have found at the same place:a bed: of pale buff coloured limestone of an earthy fracture, punctured’ with holes: not larger than a needle’s point. The ornamental parts of the old exchange at Newcastle were carved’ out of these two varieties of stone. The four lowest strata. of Mr. Goodchild’s quarries at Pallion near Sunderland, constitute another variety. Its colour is a dirty light brown; but taking a tolerably good polish it is sold as a marble. In lustre and hardness it resembles a stalagmite ; it is met with at the depth of eleven fathoms from the surface. In Castle Eden Dean: there are cliffs of this rock well worthy of notice; and the perforated rocks at Marsden and Hartlepool, and the caverns at the latter place, at Black-hall. near Easington, and on the coast near Monk Wearmouth, deserve the attention of the geologist. These curious and picturesque objects appear to have been formed at no very distant date by the action at the sea, which has dissolved and washed out the soft. marly limestone, with: 8 Mr. N. J. Wincu on the Geology of which the cavities of these rocks were once filled. From this cause the promontory, on which Hartlepool stands, is rapidly crumbling away. , It is well ascertained that the magnesian limestone of this district, as is the case with that of Derbyshire and Yorkshire, rests upon the coal-measures. No coal mine however has yet been won in Northumberland or Durham, by sinking a shaft through the lime- stone, although the workings of some collieries situated on its western boundary have been carried underneath it. It is therefore a matter of great importance to those who have royalties within its limits to know under what thickness of limestone the coal measures are buried ; whether after passing under the limestone they continue to dip at the same angle as before, and whether the quality or thickness of the coal-seams is then altered. I have not been able to ascertain what is the total thickness of the limestone ; but at Hart, near to Hartlepool, a bore-hole was made in it to the depth of 52 fathoms, without penetrating through it. This spirited undertaking was then frustrated from the per- foration being filled with sand and water. At Pallion, a little to the west of Sunderland, the limestone was only 12 fathoms thick, below which the coal measures were bored through to the depth of 140 fathoms without finding a coal seam worth working. Along the coast of Durham from Shields to Hartlepool! the lime- stone strata dip to the south-east. At Chapted main near South Shields, the coal measures, although approaching the limestone, rise towards the sea, in conformity to their direction on the north side of the Tyne; but at Painshaw, New bottle, Rainton, &c. they dip to the south-east, the limestone being there protruded into the Coal-field beyond the prolongation of that line, from which the coal measures that are without covering begin to rise in an eastern Northumberland and Durham. 9 direction. It appears therefore that their dip is not affected by the limestone. It is a circumstance however too well ascertained to admit of a doubt, though difficult to be accounted for, that the coal is deteriorated in quality where covered by the limestone. Galena is the only metallic ore that I have observed in this lime- stone. It has been found in small strings at Whitby quarry, Clacks-heugh Blackhall-rocks, Ryehope, and amongst the rocks below Tynemouth castle: at the latter place calcareous spar is the matrix. The crystallized fossils are small crystals of calcareous spar, formed in groups of acute three-sided pyramids; sometimes white and opaque; at other times~yellowish or hair brown and translucent, lining cavities of buff marly limestone; from the cliffs near South Shields and Marsden. Botryoidal masses of fetid limestone devoid of magnesia, in balls varying from the size of a pea to two feet in diameter, imbedded in soft, marly, magnesian limestone, are found at Hartlepool, in the quarry at Building hill, near Sunderland, and on the sea-coast a mile or two north of Monk Wearmouth. These balls are radiated from the center, their colour hair brown, fracture shining, cross fracture splendent approaching to vitreous: white calcareous spar is frequently observed within them. See Sowerby, Brit. Min. tab. 38. Stalactitical fetid limestone. See Sowerby, tab. 148. These cellular masses resemble corallines, and are also met with in the marly limestone above described, Organic remains are rarely met with in this limestone. The most remarkable one was found in a quarry at Low Pallion. It is the im- pression of a fish,* which appears to belong to the genus Chetodon. * See Plate 2. Vou, Iv. B 10 Mr. N. J. Wincw oz the Geology of In length it is about 81 inches, and 45 in breadth. The dorsal fin reaches from the middle of the back to the tail. | From Humbleton quarry, situated a mile from Bishop Wearmouth, on the road to Durham, I have received the following specimens, imbedded in hard buff-coloured crystalline limestone. 1, Casts of the internal part of the vertebral column of the Cap Encrinite. See Parkinson, vol. 2. tab. 10. fig. 4. 2. A species of Donax with hair-like spines. S. Casts of reticulated Alcyonite. Parkinson, vol. 2. tab. 10, fig, 1, 2, 3. 4, Smooth shelled bivalves, from the size of a pea to that of a cockle, resembling those of the genus Donax. 5. Small round bodies, delineated by Parkinson, vol. 2. tab. 8. fig. 10. gi 6. Casts of bivalves, resembling muscles. 7. Casts of Arce and Anomiz. Sowerby, Brit. Min. tab. 55. 8. Impressions of a reticulated marine production resembling the genus Flustra. Ill. Coal Measures. The coal-seams and the rocky strata which together constitute the coal-formation of Newcastle and Sunderland, are in part covered by the magnesian limestone, and rest upon the lead-mine measures. They occupy a hollow, or trough, of which the extreme length from the Aklington colliery, near the Coquet, in the north, to Cockfield, in the neighbourhood of West-Auckland, is 58 miles; and the breadth, from Bywill on the Tyne, to the sea-shore, is 24 miles. This formation first makes its appearance on the south bank. of the Northumberland and Durham. il Coquet, near that river’s junction with the sea, and bounds the coast of Northumberland in a south-south-eastern direction for 23 miles. It then crosses the mouth of the Tyne; after which the magnesian limestone begins to cover a part of it, and continues to intrude more and more upon it until both approach the Tees. The distance from South Shields to Cockfield is 32 miles in a south-westerly direction. The western side of this district cannot be so easily defined, since many of the lead-mine measures strongly resemble those of the coal- field; but when the Mill-stone grit (a coarse-grained sandstone so called) and the Blue Encrinal limestone, are seen cropping out, one may then be sure that the boundary of the coal formation is passed. However, if a line be drawn from the vicinity of Aklington on the Coquet, to cross the Tyne at Bywill, the Derwent near Allansford, and the Wear below Wolsingham, and to terminate at Cockfield, a tolerably correct idea may be formed of its western limits. This district is characterized by low round-topped hills, which rise gently from the sea, and increase in height towards the west. Pontop pike, situated on the Derwent, not far from the western boundary of the coal-field, is reckoned by Mr. Fenwick of Dipton, to be very near 1000 feet high, and a pit sunk near the summit proves that it cannot be much less, That part of Newcastle Leases which lies close to Spring Gardens, and the western turnpike gate, is ascertained to be 190 feet above the level of the Tyne, and 205 above the sea. Ben- well hills to the west, and Gateshead Fell to the south, are some- what higher. The inequality of the surface does not affect the dip or inclination of the coal measures; and when they are interrupted or cut off by the intervention of a valley, they will be found on the sides of the opposite hills at the same levels, as if the beds had been continuous. Thus the Grindstone bed may be seen on Byker hill, Gateshead B2 12 Mr. N. J. Wincn on the Geology of Fell, and Whickham Banks, though no where in the vales of the Tyne and the Team, which severally intersect those elevated por- tions of land. The conclusion is obvious, that the present irregu- larity of hill and dale has been occasioned by the partial destruction and dispersion of the uppermost rocky masses, which constitute the coal formation. That part of the trough in which the greatest thickness of the coal measures is found, seems to lie in the vicinity of Jarrow; and from this point the beds appear to rise to some considerable distance on each side, particularly in a western direction. The average dip of the coal measures is 1 inch in 20; but this inclination is by no means uniform in every part of the district. Thus that seam of coal called the High Main which lies buried at Jarrow, under 160 fathoms of beds of stone, soon rises to the clay in a north-easterly direction, and bassets out in the cliffs between Cullercoats and Tynemouth. In its north-westerly range it reaches Benwell hills, and at Pontop nearly 18 miles due west of the sea shore at Sunderland it is met with at 3814 fathoms from the surface. In a southerly direction it is found at 52 fathoms on Gateshead Fell, but bassets out before it reaches the Wear. | The principal substances besides coal, which constitute the Coal formation, are shale and sandstone ; which as they vary in hardness or colour receive different provincial names from the miners. It is not possible to discover in the Coal measures any regular order of succession, which will apply to the whole Coalfield, and it is even with difficulty that in very limited portions of it the continuity of particular seams can be traced. This arises from the variable thick- ness and the rapid enlargement and contraction of the different beds; that which in one section is scarcely perceptible, having at- tained in a neighbouring pit the thickness of several fathoms. It is Northumberland and Durham. 13 thus that the Five Quarter coal seam of the mines on the Wear is divided into the Metal and Stone-Coal seams of Sheriff Hill, and that the Low-main seam of the Wear becomes the Five Quarter and Six Quarter seams of the Tyne and Gateshead Fell. Thus also in Brandling and Hebburn collieries a parting of stone first divides and afterwards usurps the place of the High Main coal seam ; and thus the two upper coal seams that are well worth working (see the section of Montague colliery north) at Kenton, are no longer so in the neighbouring colliery of Killingworth. ‘The following is an account of a similar occurrence in Montague colliery, abridged from an unpublished Memoir, by Mr. Thomas, of Denton, on the dykes found in that mine. Within the Newbiggin Stone-Coal seam, at 20 inches from the floor, there is a band of a soft clayey substance 13 inch thick: but the band encreasing in thickness to- wards the east, the coal is divided into two distinct seams, whose ageregate thickness is less than that of the original seam. At the distance of 1000 yards to the east, and 300 yards north of the main dyke,* the band is 24 feet thick ; the upper coal seam 6 inches ; the lower 16 inches. The band decreases towards the north at the rate of something more than 1 inch per yard ; and the coal at the same time increasing, the upper and lower parts are so nearly united at the distance of 160 yards, as to form again a workable seam. The upper coal then measures 21 inches, the lower 24, and the band 15. It is useless therefore to attempt any general section of the Coal formation ; and it will be seen in the sections subjoined to this paper, how difficult it is from want of uniformity in the beds to identify the coal seams in the vicinity of Newcastle. I refer to the * The Ninety-fathom Dyke described hereafter. 14 Mr. N. J. Wincu on the Geology of sections of Hebburn and of Sheriff hill, as exhibiting when taken in succession, a series of Coal measures of the thickness of about 270 fathoms. In the former colliery are the beds which lie above the High Main coal; in the latter principally those which lie beneath it ; together they present the entire order of the coal seams, that are best understood in the Newcastle district: but it will be seen even in these two examples, what want of agreement there is in the beds which lie in the two sections above the High Main coal. The most valuable seam in the whole Coalfield in point of thick- ness and quality is that called the High Main, of the mines situated between Newcastle and Shields. It there averages above 6 feet from the roof to the floor, contains a large proportion of bitumen, and is sufficiently hard to bear carriage without breaking into very small fragments. From this the owners of Old Byker, Byker St. Anthony’s, Walker, Walker Hill, Willington, Old Benton, and Flatworth mines, formerly drew their riches; and it continues to supply the present proprietors of Hartley, Blyth, and Cowpen, north of the 90 fathom Dyke; of Heaton, Bigge’s Main, Wall’s End, Pevey Main, Colling- wood Main, and Murton Collieries on the north side of the Tyne, and of Hebburn, Jarrow, and Manor’s Wall’s End, on the south side of that river. I have already described in part the basseting of this coal seam along the course of an eval line, of which Jarrow is the centre; from which some idea may be formed of the extent of country which it underlies north of the 90 fathom Dyke. At a land-sale pit, a little above the Ouse burn Bridge, near Newcastle, this seam was found at 14 fathoms; but on the Town-moor, from the numerous vestiges of ancient pits, it appears to be exhausted. The lower seams under the same lands are without doubt un- touched. Wallis, in the history of Northumberland, gives an account of a fire happening in the High Main coal, about 140 years f. Northumberland and Durham. 15 ago, on the Town-moor and Fenham estates, which continued to burn for 30 years. It began at Benwell about a quarter of a mile north of the Tyne, and at last extended itself northward into the grounds of Fenham, nearly a mile from where it first appeared. There were eruptions at Fenham in nearly 20 places; sulphur and sal-ammoniac being sublimed from the apertures ; but no stones of magnitude ejected.* Red ashes and burnt clay, the relics of this pseudo-volcano, are still to be seen on the western declivity of | Benwell hill, and it is credibly reported that the soil in some parts of the Fenham estate, has been rendered unproductive by the action of the fire. At Byker St. Anthony’s, and at an adjoining ¢olliery, the Low Main coal is found at 59 fathoms below the High Main; but though the seam proved to be 63 feet thick, the workings of it were abandoned as unprofitable ; the coal being extremely fragile, and the mines very subject to the fire damp. On the south side of the Tyne, at Felling, Tyne Main, and Gateshead Fell, the quality of this coal is very much improved, and under the name of the Hutton Main, it forms one of the most valuable seams on the Wear. I must refer to the series of sections for a more complete view of the other coal seams. I now proceed to give a more particular account of the sub- stances that form the coal measures. Of the coal itself three varieties are found ; the common or Slate coal, Cannel coal, here called Splut, or Parrot coal, and Coarse coal, also called Splint. The texture of fine splint is compact, the cross fracture con- choidal, and the fragments are cubical. Coarse coal is slaty in its * See a paper by Dr. Lucas Hodgson, on the Salt sublimed, in the Phil. Trans. No. 130. & 16 Mr. N. J. Wincu on the Geology of texture, and it seems to be intermediate between common and cannel coal. These varieties are not found to occupy separate and peculiar seams of the coal formation, but alternate irregularly with one another, as layers of the same bed. At Wylam they are met with in the following order. Feet { In. At 6 fathoms ....|High main ON, Aver Five quarter..... ae Splint coal is also found at Throckley, Kenton, and some of the Lambton collieries situated on the Wear. Coarse coal occurs at Cockfield and many other places. These two varieties, containing little bitumen and less sulphur, are used in iron founderies, pot- teries, &c.; and splint serves as a material for building cottages and outhouses in the neighbourhood of Throckley Fell. Potters’ clay is found immediately below the vegetable soil. Its colour is blueish or smoke grey, and sometimes yellow approaching to orange, in consequence of a mixture of iron ochre. It is used in the manufacture of coarse earthenware, bricks, and tiles. 2A Northumberland and Durham. 17 Shale or slate-clay is found throughout the Coal field, possessing various shades of colour and degrees of induration. Hard black and dark grey shale is called Black metal by the miners; it is used by the manufacturers of potters’ saggers and fire-bricks, but for the latter purpose Thi/-whin, or hard bituminous shale forming the floor of the coal seams, is preferred.* Shale of a blueish grey colour is called Blue metal. A blue bituminous shale, lying imme- diately below the coal, is called Blue-thil, . Hard blue metal is one of the most common measures in the coal-field ; it is a mixture of shale and sandstone, sometimes con- taining scales of mica; is much harder than Blue metal, and from its waved structure breaks into sharp wedge-shaped fragments. Its colour varies from ash-grey to iron-grey. Clay-stone (of Jameson) is not very common; it varies in colour from black to ash-grey, and is the Black-stone or Blue-stone of the miners, (vide St. Anthony’s section,) it is fine-grained in texture, and breaks into angular fragments. The following are the principal varieties of sandstone that occur. White flagstone plate: a greyish-white argillaceous sandstone, hard and breaking into sharp wedge-shaped fragments. It is quar- ried for flag-stone at Heworth and on Gateshead Fell, where it is about two fathoms thick. Grindstone. sill or post: a light yellowish or buff-coloured fine- grained sandstone, loosely aggregated, and therefore not very hard. It crops out on Byker Hill, Whickham Banks, and Gateshead Fell, where it is about 11 fathoms thick. It is quarried for the well known Newcastle grindstones, and from its softer parts filtering stones are made. In many places the upper part of this bed is * Stourbridge clay is imported for the glass-house pots. VOL. IV. c 18 Mr. N. J. Wincu on the Geology of abundantly impregnated with yellow ochre, which is sold under the name of die-sand. Fire-stone resembles the grindstone in colour and fracture, but is soft when first worked. The best is quarried at Burradon near ‘Killingworth: glass-house furnaces are constructed with it. White post is a fine-grained sandstone, tolerably hard. White post with whin consists of alternate laminz of soft and hard sandstone. Grey post is a fine grained sandstone, containing a large admixture of clay and sometimes of mica. Brown post is a slaty micaceous sandstone. Brown post with Coal pipes is a laminated sandstone traversed by strings of black shale and coal, Brown post with skamy partings is a light brown sandstone with dark brown lamine. Grey whin or Brown whin is a very hard dirty-brown quartzose sandstone, sometimes specked with minute white dots, and at other times containing very small scales of mica: it strongly resembles granular quartz. A bed of this rock may be seen contiguous to the basaltic dyke in Walbottle Dean. What is called by the miners Band in coal is commonly com- posed of bituminous shale, clay and iron pyrites; sometimes of sandstone. Girdle means a thin plate: thus Post girdles are layers of sandstone; Whin girdles in post are layers of hard quartzose sandstone in softer sandstone ; and Whin girdles in shale are thin beds of argillaceous iron ore in shale. The minerals that accompany the coal measures are, Clay ironstone, forming either thin beds or nodules (catheads ) in the shale. Northumberland and Durham. 19 Galena is found together with pyrites in the nodules of clay-iron- stone, that are imbedded in the shale; as at Montagu main, at the depth of 40 fathoms, Iron pyrites is found in great adaiunien crystallized and dis- seminated in the beds both of coal and of shale; it is sold to the manufacturers of green vitriol, Azure iron ore is not uncommon in the potters’ clay at Elswick, and in other brick fields, Calcareous spar is common, either blended with the coal or in the form of stalagmites. The Organic remains found in the coal measures are, Impressions of plants resembling those of the genera fontinalis and equisetum, except that the latter are destitute of the jointed stem of the true equiseta. In shale, A fern, like polypodium filix mas, (Parkinson, vol. i. tab. 4. fig. 7.) Impressions of plants, (vide Parkinson, vol. i. tab. 3, fig. 6, 7.) In shale. A fern, like blechnum boreale, (Parkinson, tab. 4. fig. 1, 2. and Sowerby, tab. 296.) and another like osmunda regalis ; from Kenton colliery, and from the shale contiguous to the Coley hill dyke. In nodules of clay iron-stone. Impressions of cones, (Parkinson, vol. i, tab. 9. fig. 1.) from Urpeth Dean, Durham. In nodules of clay ironstone. Obscure impressions of a fern, from Murton colliery. In nodules of clay ironstone. Large flattened lumps of iron pyrites, bearing the form of the stem and the impression of the bark of a plant resembling an euphorbia; called by the miners fetrified salmon. From the floor of several collieries, c2 20 Mr. N. J. Wincu on the Geology of Impressions of the bark of a plant resembling a cactus or euphor- bia, (Sowerby, tab. 49.) from Murton Main colliery; and (Parkinson, vol. i. tab. 1. fig. G.) from Benwell colliery. In coal. Vegetable impressions (vide Parkinson, vol. i. tab. 3. fig. 1.) from Gateshead Fell. In sandstone. . Cast of a cane-like vegetable, (Parkinson, vol. i. tab. 3. fig. 3.) from near Coley hill dyke; and (Parkinson, vol. i. tab. 5. fig. 8.) from Muston colliery. An aggregate of black quartz crystals diverging from centres ; having the interstices filled with yellow ochre. It is a mineralized tree, and it found at Bigge’s main colliery, and often in large masses on the sea beach. : Bivalve shells * resembling those of the freshwater muscle, in dark-grey ironstone, from Wylam and Muston collieries. Bivalve shells resembling the preceding but much less in size, in a stratum of black shale and ironstone ; from the rocks in the Tyne at Low Lights, and from Heaton Dean, near Busy cottage. Bivalve shells like the last, about half the size of freshwater muscle shells, in black shale, from Hebburn colliery, at the depth of 130 fathoms. ‘These shells are generally less common in the shale than in the ironstone that accompanies it. I have only to remark on the preceding catalogue that it contains no marine genera; and I do not believe that any marine shells, zoophytes, or corallines have ever been detected in the coal mea- sures of this district. ~ * Very similar shells are found in the Clackmannanshire coal-field at North Alloa, in that of Staffordshire at 'Tividale, and ‘in the great coal-field of Derbyshire and Yorkshire, where the bed of ironstone that contains them is called the Muscle band. [Communicated by Mr. Warburton. ] Northumberland and Durham. 21 The dykes of basalt or greenstone, that intersect the coal mea- sures, are among the most remarkable occurrences in the Coalfield. The most considerable basaltic dyke in the immediate neigh- bourhood of Newcastle is that which passes through Coley hill, about 4 miles west of the town. A long range of quarries has here been opened upon it, in some places to the depth of 50 feet, and laying bare the entire width of the dyke, which is 24 feet. The dyke in this place appears to have no hade. The basalt of which it is composed is found in detached masses coated with yellow ochre. The removal of these brings to view thin layers of indurated clay with which the fissure is lined, and which break- ing into small quadrangular prisms is used by the country people for whetstones: in this substance clay ironstone impressed with the figures of ferns is very abundant. The upper seam of coal is here found at about 35 feet from the surface, and where in con- tact with the dyke is completely charred, forming an ash-grey porous mass, which breaks into small columnar concretions, ex- actly resembling the coak obtained by baking coal in close iron cylinders in the process of distilling coal-tar. Calcareous spar and sulphur are disseminated through the pores of this substance. The basalt itself when broken is of a greenish-black colour, and of a coarse grained fracture. It contains quartz, calcareous spar, and another mineral, possessing the following characters. The colour is wax-yellow passing into olive-green; the lustre vitreous, resembling that of glassy felspar; the fracture foliated. It resists the action of the blow-pipe without borax, but with it melts into a white glass. The latter circumstance, and the foliated fracture distinguish this substance from olivine, which gives a dark green bead with borax, and presents a fracture more or less conchoidal. Passing to the east-south-east of the Coley hill dyke in the line 22 Mr. N. J. Wincu on the Geology of of its direction a vein is found traversing Walker colliery, and_ crossing the Tyne at Walker near Mr. Reay’s house, In the latter colliery it has been observed and described by Mr. George Hill, to whose accuracy I owe the plan given in Plate 3, and the following particulars. The dyke is well defined, and the Plate represents its horizontal section taken at the level of the high main coal ]00 fathoms from the surface. It occasions no alteration in the level of the coal- measures, and the depth to which it intersects them is unknown, The dyke has been cut through by horizontal drifts in four places, from which the following sections have been taken, Sections at A. A. the two western drifts. Lieako Nige2.294 a Ls . Gov & arth wetiwe o4 2. Hard greenish rRrratanes firm and ainbeaicon ye 3—-— 3. A fissure filled with nodules of whinstone and sa dnedted inacement ofblue slate ..... 2 —— g 4. Loose fragments of whinstone and post EE: in tals slate but commonly less GeRAmGed. 6 fee ve. he Bye, 3 5. Hard greenish whinstone Sinn to Nols. 2802 OUT? Ge ae 6.iGeak: 22 oc'thal ia) «0 spicleea og oihlideb! Peewee Bi bell 1G Yards 22 1 6 Sections at B. B. the two eastern drifts. Led . Coak very hard ase yas te Oey its oe es 6 w, 1 — 2. A confused mixture of nodules of Laiiene ‘ilinetone pyrites and calcareous spar (the sandstone predominating) cemented together by pieces of blue and black slate. Water was found, > 6 — — and there was a plentiful discharge of inflammable gas, while the drift was being made. . . a of 3. Compact post, with pieces of black sheet eet slate occurring dt-intervals: 257, 4398 Be eT OTP) ASN ia oe 3 BrTTIVG. 4, Hard greenish whinstone,» i) sé, 2/6 Sayih euecpeelie) oad ee @.;CGoak like that of No. lL... 4's eo ee & el ee eee Northumberland and Durham. 23 Further to the south-east and in the line of the direction of the Walker dyke, a ‘small quarry of basalt was formerly worked about 1 mile north of Boldon hills. The rock was fine grained, nearly black, and filled with small globules of milk white chalcedony, not bigger than a mustard seed. With regard to the basaltic rocks of Coley hill, Walker, and Boldon, it is by no means well ascertained that they are portions of the same dyke, connected together below the surface; since no trace of that of Coley hill could be discovered in the very extensive and ancient collieries of Montagu and Kenton, situated in its course at a short distance to the east of it; nor was the Walker dyke found in any other colliery. At Walbottle Dean, 55 miles west of Newcastle, below the bridge on the western road, a double vein of basalt* crosses the ravine in a diagonal direction, passing nearly due east and west. It hades to the north at an angle of 78°, and cuts the coal-measures without altering their dip. On the eastern bank of the ravine it is laid bare from the level of the brook to the height of about 60 feet. The northern and southern basaltic portions of the vein, the one 5 the other 6 feet in thickness, are there 13 feet apart, and are sepa- rated from one another by a confused heap of fragments of sand- stone and shale broken from the coal-measures. With these frag- ments are found balls of basaltic tufa parting into concentric layers, and of a light yellowish brown colour: the balls are most abundant on the sides of the rubble near to the basalt. Where the dyke reaches the surface a quarry of the basalt was formerly worked, which has lately been cleared. A small seam of coal meets the basalt at no great depth from the quarry-head, but * Plate 4, fig. 2. 24 Mr. N. J. Wincu on the Geology of the place of contact is at present inaccessible. In the neighbouring colliery both portions of the vein hold their course through the seam there worked, and the coal is charred by their influence. Some of the blocks from the quarry are quite black, and of an earthy fracture, and contain nodules of quartz and chalcedony, varying in magnitude from the size of a pin’s head to that of a large pea. Other specimens of the rock are hard, coarse grained, and of an iron-grey colour; but in neither varieties have I found the mineral resembling adularia, so abundant in the basalt of Coley hill. A basaltic dyke 6 feet wide may be seen among the rocks of the ccal formation at the south-eastern corner of the promontory on which Tynemouth castle stands. Another, about 3 yards wide, appears in the cliffs near Seaton sluice ; its direction is west-north- west, and it may again be seen in Hartley burn. A small whin dyke was formerly quarried near Bedlington; and another is found in Cowpen colliery, which has charred the coal in contact with it. Passing to the south of Newcastle about 2 miles beyond Durham, a basaltic vein may be seen, when the water is low, at Butterby in the bed of the Wear. This vein is remarkable for a salt spring that issues from its interstices, and for a string of galena (first noticed by Mr. Fenwick of Dipton) that fills a crevice beside it. Two miles further to the south near the junction of the Auckland and Darlington roads, is another dyke, the direction of which is nearly east and west, and on which two quarries are worked, each about 10 feet wide. Of the Cockfield dyke a section and description have been given in the History of Durham, by the late Mr. Dixon, from which work I derive the following particulars. This dyke passes in a north-west and south-east direction from Northumberland and Durham. 25 Cockfield to Botain, situated on the western boundary of the mag- nesian limestone. Its width is 17 feet at the former place, where it hades to the south, and throws up the coal-measures on that side 3 fathoms. The low main coal contiguous to the basalt is only 9 inches thick, but enlarges to 6 feet at the distance of 50 yards from it. The coal is reduced to a cinder, and the sulphur is sublimed from the pyrites near to the dyke. I have never been able to trace any of these basaltic veins into the magnesian limestone, and am almost certain that together with the other members of the coal formation, they are covered by it. Continuing the line of direction of the Cockfield dyke from Botain to the south-east, after passing the eastern boundary of the magnesian limestone, we meet with a dyke on the banks of the Tees a little below Yarm. It there cuts the red sandstone, and continuing its course in the same direction is well known to tra- verse the north-eastern part of Yorkshire. Besides the fissures filled with basalt, others of a very different nature intersect the Coal-field. These if large are also called dykes, but, if inconsiderable, troubles, slips or bitches; and are the same that some geologists have called faults. I have already noticed the main or ninety-fathom-dyke, when speaking of the limestone quarry at Whitley, where it is seen dividing the coal-measures in the cliff, and passing into the sea. It receives its name from the degree of throw which generally attends it in the strata through which it passes, and which are cast down on the northern side about 90 fathoms. At Whitley the same bed of coal which is found at 7 fathoms on the southern side of it, is found at 50 on the northern, the measures being there thrown up on the southern side 43 fathoms. From this point the dyke ranges, though not in a straight line, through that part of VoL. Iv. D 26 Mr. N..J. Wincu on the Geology of the country formerly called Killingworth moor, and. passing: near Gosforth church, Denton hall, and by the north corner of the field east of W. Denton’s house, crosses the Tyne in the direction of Reyton church, and proceeds to the south-west by Greenside and Lead-gate. Farther it has not been traced; but it is highly probable that it traverses the lead mine district; and produces lateral and valuable metalliferous veins therein. It will appear from the two subjoined sections of Montagu Colliery, taken from opposite sides of this fissure, that 11 seams of coal (two of which are worth working) together with their accom- panying strata which are found on the northern side, have dis- appeared on the southern. The exact throw in the measures occasioned by the dyke cannot be ascertained from these sec- tions, one of them being that of a pit near to Scott’s wood close to the Tyne, the other belonging to a shaft sunk in much higher ground 13 mile north of the former. _* The hade of the dyke in this colliery is imperceptible: the space between the cheeks measures about 22 yards, and is filled with soft and hard sandstone. A perpendicular fissure, the sides of which are quite smooth, divides the stony contents of the dyke into two equal parts, and when perforated was found to be filled with soft clay and water. On the south side the coal-measures preserve their usual dip of 5° until close to the dyke: on the northern from the distance of 150 yards they rise to the dyke at an angle of 20°, but at the distance of 600 yards they regain their accustomed position. In some parts the coal is deteriorated in quality to the * I have extracted these particulars from a memoir on the Montagu colliery, by Mr. Thomas, of Denton, in which are described the dykes and slips met with in the workings of that mine. I am partly indebted to the same gentleman for the information on thé. ‘direction of the main dyke. Northumberland and Durham. 27 distance of 20 yards from the dyke ; but in others to that of 3 or 4 yards only. From the southern side of the main dyke two others branch off, one to the south-east, the other to the south-west. The latter is called from its breadth the 70 yard dyke, and is filled with a body of hard and soft sandstone. This intersects the upper or Beaumont seam, which is not thrown out of its level by the interruption. The seam however decreases in thickness from the distance of 15 or 16 yards, and the coal first becomes sooty, and at length assumes the appearance of coak. This phenomenon is ipkhewn elsewhere except in the vicinity of basaltic dykes. The south eastern branch is only 20 yards in breadth, and hard white sandstone together with other rocky fragments fill the cavity, and are in part cemented together by calcareous spar. Although the strata ate thrown up only 20 feet on the north-eastern side of the vein, yet great confusion has taken place in its vicinity, and much water was found to issue froin it. From the northern side of this part of the main dyke many small slips extend, some of which alter the level of the Newbiggin coal- seam without affecting that of the Kenton seam lying only 13 fathoms above it. * The Birtley, Tantoby or Tanfield Brkoct is next in magnitude and length after the main dyke. From Tatfield on the Wear it ranges towards the west, passing through Leefield, Ouston, Birtley Fell, and Urpeth collieries: thence in the direction of Beamish hall it traverses Tanfield Moor, and crosses the Derwent near Derwent- coat Forge. In Tanfield Moor colliery it is in all an upcast on the northern side of 40 fathoms ; but instead of consisting of one strong * Tam indebted to Mr, Fenwick of Dipton for the information which follows, respect- ing the other dykes which traverse the Coal-field. D2 28 Mr. N. J. Wincu on the Geology of vein, it appears to be divided into a number of small branches, some of which are upcasts and some downcasts, which break and rend the coal-measures to the width of 200 yards. In the Wear water mines it is an upcast on the northern side of 30 fathoms. The Thistle pit dyke which is a downcast of eight fathoms to the south, and traverses the Coal-field from west to east, appears to have been as well known to the miners who lived nearly a cen- tury since, as to those of the present day. It was the southern limit of the ancient colliery situated at Heaton and Benton banks, and by perforating it the mine at Heaton was inundated on the 3d of May, 1815, when the viewer and seventy-four men and boys lost their livess—For an account of this catastrophe, see Monthly Magazine and Philosophical Journal. The Heworth dyke is an upcast on the southern side of 25 fathoms, and from the vicinity of Falling hall it stretches towards the west, and enters the main dyke at Ryton. The high-main coal to the south of this dyke is said to lose a strong parting known by the name of Heworth band. At Hebburn, Oxclose, Ravensworth, Lambton, Newbottle, Lum- ley, Raynton, and every other colliery worked in the district, simi- lar dykes occur; and, following the same law as the veins of the Lead-mine district, they elevate the strata on that side towards which they dip. Whatever be the throw or difference of level occasioned in the coal-measures by these dykes, it never happens, as might be expected, that a precipitous face of rock is left on the elevated side; or that the lower side is covered by an alluvial deposit, which connects the inequality of the beds that are in situ ; but the surface of the ground covering the vein is rendered level by the absolute removal of the rocky strata on the elevated side. The same phenomena have been Northumberland and Durham. 29 observed in other parts of the kingdom; and render evident the operation of a most powerful agent employed in tearing up the surface, and in dispersing the fragments of the ruin. In the coal measures near the edges of those dykes rounded pebbles of sandstone and fragments of coal cemented together by sand are sometimes met with; as in Lawson main, Sheriff hill, and Montagu Main collieries. Galena has been found in a dyke in Willington colliery, and a small string of the same ore has been observed in the main dyke at Whitley. A salt spring issues from a slip in Birtley colliery. ‘The dykes are an endless source of difficulty and expense to the coal owner, throwing the seams out of their levels, and filling the mines with water and fire damp. At the same time they are not without their use; when veins are filled, as is often the case, with stiff clay, numerous springs are damned up and brought to the surface ; and by means of downcast dykes valuable beds of coal are preserved, which would otherwise have cropped out and been lost altogether. Thus the high-main, the five-quarter, and the seven- quarter coal seams would not now have existed in the country to the north of the main dyke but for the i depression of the beds occasioned by that chasm. The other irregularities observed in the coal measures are the following : 1. Large wedge-shaped portions of the strata that are occasion- ally found to have sunk from their level. This occurrence was noticed in Cockfield colliery by Mr. Dixon, and a section of it is given in the history of Durham. A much more serious difficulty of the same kind was surmounted within these few years in Hebburn colliery by Mr. Buddle. 2. Fissures that divide the strata, but do not alter their level, 30 Mr. N. J. Wincu on the Geology of and which sometimes do not descend lower than the upper seams of coal. These are called gashes by Williams, and washes by our miners: they are filled with water, clay, sand, and rounded sand- stone sh i similar to those in the beds of rivulets. . Basin-formed depressions in the floors of the mines, edited suiellie by the miners; by which the coal is considerably thickened, the roof of the seam preserving its regularity. These occur when the coal is nearly horizontal. 4. Nips, where the coal nearly disappears, the floor and the roof coming into contact. Near Fawlon Slate in the neighbour- hood of Fenham, 80 acres of coal are said to be lost in this manner. At Hetton and at Hebburn, and in other parts of the Coal-field, the coal-measures are covered by large tracts of quicksand, which appear to have been the beds of ancient lakes. Mr. Fenwick has lately penetrated through a most formidable obstruction of this kind at Hetton by means of a number of cast-iron cylinders. Having now given a general account of the coal beds, and of the derangements to which they are subject, I proceed to the Colliery Sections, with which I commence on the northern side of the main dyke near the sea, and thence pass towards the west: then crossing to the southern side of the main dyke at Montagu colliery and returning to the east, I exhibit the strata pierced at some of the principal collieries on the Tyne, and the lower beds found at Gateshead Fell and on the Wear. Some other examples follow, which are taken from the western and south-western borders of the Coal-field. | Northumberland and Durham. Section of the Strata at Hartley Colliery. Clay, Sand, &c. to the Coal- Post : 4 White post A . . Benton Seam . Clay ° Grounp Coat . Thil of ditto 4 Blue Metal Black ditto Blue ditto Fs ; Black ditto . : Grey ditto with girdles : Blue ditto . > . Merat Coat . : Thil : Grey Metal with post girdles White post : . Whin . . ° White post . ° Blue Metal . . White post . é Grey Metal with girdles White post . . Grey Metal S Blue ditto Mixep Coat and SronE Black Stone White post Grey Metal. Post girdle . Grey Metal Post girdles. Grey Metal : Blue ditto - White post . - Blue Stone Yarp Coats. feel Eri Beebo Ghar ies Ca eee a ees ed ed ee es err ere er rec eon el reser belied prewar br Carried forward Fs. or Nj _ Heacatlatl "|