CHAPTER XXIX The Carboniferous Volcanoes of England | |
| PAGE | |
| The North of England: Dykes, Great Whin Sill—The Derbyshire Toadstones—The Isle of Man—East Somerset—Devonshire | [1] |
CHAPTER XXX The Carboniferous Volcanoes of Ireland | |
| King's County—The Limerick Basin—The Volcanic Breccias of Doubtful Age in County Cork | [37] |
BOOK VII THE PERMIAN VOLCANOES CHAPTER XXXI The Permian Volcanoes of Scotland | |
| Geographical Changes at the Close of the Carboniferous Period—Land and Inland-Seas of Permian time—General Characteristics and Nature of the Materials erupted—Structure of the several Volcanic Districts: 1. Ayrshire, Nithsdale, Annandale; 2. Basin of the Firth of Forth | [53] |
CHAPTER XXXII Permian Volcanoes of England | |
| The Devonshire Centre—Eruptive Rocks of the Midland Coal-fields | [94] |
BOOK VIII THE VOLCANOES OF TERTIARY TIME CHAPTER XXXIII | |
| Vast lapse of time between the close of the Palæozoic and beginning of the Tertiary Volcanic Eruptions—Prolonged Volcanic Quiescence—Progress of Investigation among the Tertiary Volcanic Series of Britain | [107] |
CHAPTER XXXIV The System of Dykes in the Tertiary Volcanic Series | |
| Geographical Distribution—Two Types of Protrusion—Nature of component Rocks—Hade—Breadth—Interruptions of Lateral Continuity—Length—Persistence of Mineral Characters | [118] |
CHAPTER XXXV The System of Dykes—continued | |
| Direction—Termination upward—Known vertical extension—Evidence as to the movement of the Molten Rock in the Fissures—Branches and Veins—Connection of Dykes with Intrusive Sheets—Intersection of Dykes—Dykes of more than one infilling—Contact metamorphism of the Dykes—Relation of the Dykes to the Geological Structure of the Districts which they traverse—Data for estimating the Geological Age of the Dykes—Origin and History of the Dykes | [145] |
CHAPTER XXXVI The Plateaux | |
| Nature and Arrangement of the Rocks: 1. Lavas.—Basalts, Dolerites, Andesites—Structure of the Lavas in the Field—2. Fragmental Rocks.—Agglomerates, Conglomerates, and Breccias—Tuffs and their accompaniments | [181] |
CHAPTER XXXVII | |
| The Several Basalt-Plateaux and their Geological History—Antrim, Mull, Morven and Ardnamurchan | [199] |
CHAPTER XXXVIII | |
| The Basalt-Plateau of the Parish of Small Isles—Rivers of the Volcanic Period | [215] |
CHAPTER XXXIX | |
| The Basalt-Plateaux of Skye and of the Faroe Isles | [249] |
CHAPTER XL | |
| The Modern Volcanoes of Iceland as illustrative of the Tertiary Volcanic History of North-Western Europe | [260] |
CHAPTER XLI The Eruptive Vents of the Basalt-Plateaux | |
| Vents filled with Basalt or other Lava-form Rock—Vents filled with Agglomerate | [270] |
CHAPTER XLII | |
| The Basic Sills of the Basalt-Plateaux | [298] |
CHAPTER XLIII The Bosses and Sheets of Gabbro | |
| Petrography of the Rocks—Relations of the Gabbros to the other members of the Volcanic series—Description of the Gabbro districts—Skye | [327] |
CHAPTER XLIV | |
| The Bosses and Sheets of Gabbro in the Districts of Rum, Ardnamurchan, Mull, St. Kilda and North-East Ireland. History of the Gabbro Intrusions | [349] |
CHAPTER XLV The Acid Rocks | |
| Their Petrography—Their Stratigraphical Position and its Analogies in Central France | [364] |
CHAPTER XLVI | |
| Types of Structure in the Acid Rocks—Bosses | [378] |
CHAPTER XLVII | |
| The Acid Bosses of Mull, Small Isles, St. Kilda, Arran, and the North-East of Ireland | [395] |
CHAPTER XLVIII | |
| The Acid Sills, Dykes and Veins | [430] |
CHAPTER XLIX | |
| The Subsidences and Dislocations of the Plateaux | [447] |
CHAPTER L | |
| Effects of Denudation | [455] |
CHAPTER LI | |
| Summary and General Deductions | [466] |
LIST OF ILLUSTRATIONS
| FIG. | PAGE | |
| 176. | Section from the great Limestone escarpment on the west to the Millstone Grit hills east of Teesdale | [4] |
| 177. | Sections of the Carboniferous Limestone series of Northumberland showing the variations in the position of the Whin Sill. By Messrs. Topley and Lebour | [6] |
| 178. | View of two volcanic necks in the Carboniferous Limestone series, at Grange Mill, five miles west of Matlock Bath, from the north | [14] |
| 179. | Plan of necks and bedded tuff at Grange Mill, five miles west of Matlock Bath | [15] |
| 180. | Section across the smaller volcanic neck and the stratified tuff in Carboniferous Limestone, Grange Mill | [15] |
| 181. | Section of vesicular and amygdaloidal diabase resting on Carboniferous Limestone, Peak Forest Limeworks, Great Rocks Quarry | [19] |
| 182. | View of the superposition of Carboniferous Limestone upon toadstone, Raven's Tor, Millersdale (length about 100 feet) | [19] |
| 183. | Section at lime-kiln, south of Viaduct, Millersdale Station | [20] |
| 184. | Limestones passing under stratified tuffs, Poyll Vaaish, Isle of Man | [24] |
| 185. | Section of tuff, showing intercalations of black impure chert, west of Closenychollagh Point, near Castletown, Isle of Man | [25] |
| 186. | Section of intercalated dark limestone, shale and chert in the tuff south of Poyll Vaaish Bay, Isle of Man | [26] |
| 187. | Section of part of a volcanic neck on shore to the south-east of Poyll Vaaish Bay, Isle of Man | [29] |
| 188. | Section of successive discharges and disturbances within a volcanic vent. Scarlet Point, Isle of Man | [29] |
| 189. | Section of dyke and sill in the tuffs west of Scarlet Point, Isle of Man | [30] |
| 190. | Section on south side of vesicular sill west of Scarlet Point | [31] |
| 191. | Bands of vesicles in the same sill | [31] |
| 192. | Croghan Hill, King's County, from S.S.W. | [38] |
| 193. | Section in quarry on roadside east of Limerick, close to viaduct of the Limerick and Erris Railway | [44] |
| 194. | Section of the volcanic escarpment, east of Shehan's Cross-roads, south of Limerick | [45] |
| 195. | View of Derk Hill, a volcanic neck on the south side of the Limerick basin | [47] |
| 196. | Section across the Limerick volcanic basin | [48] |
| 197. | Section of a bed of volcanic breccia in the Carboniferous Slate; White Bull Head, County Cork | [50] |
| 198. | Volcanic breccia invading and enclosing Carboniferous slate, White Bull Head | [50] |
| 199. | General section across the Permian basin of Ayrshire | [59] |
| 200. | Section of lavas, east side of Mauchline Hill | [60] |
| 201. | Section of the top of the volcanic series near Eastside Cottage, Carron Water, Nithsdale | [60] |
| 202. | Section of two outliers of the Permian volcanic series at the foot of Windyhill Burn, Water of Ae, Dumfriesshire | [61] |
| 203. | The Green Hill, Waterside, Dalmellington, from the south; a tuff-neck of Permian age | [62] |
| 204. | Patna Hill from the Doon Bridge, Ayrshire; a tuff-neck of Permian age | [63] |
| 205. | Ground plans of Permian volcanic vents from the Ayrshire Coal-field. On the scale of six inches to a mile | [64] |
| 206. | Section of sills traversing the Permian volcanic series. River Ayr, Ballochmyle | [66] |
| 207. | Section showing the relations of the later rocks of Arthur Seat | [68] |
| 208. | Section in brooks between Bonny town and Baldastard, Largo | [70] |
| 209. | View of Largo Law from the east | [71] |
| 210. | View of small neck in Calciferous Sandstones, on the shore, three miles east from St. Andrews | [72] |
| 211. | Ground-plan of Permian volcanic vents | [73] |
| 212. | Small neck in Calciferous Sandstones a little east from the "Rock and Spindle," two and a half miles east from St. Andrews | [74] |
| 213. | Plan of volcanic necks at Kellie Law, East of Fife, on the scale of three inches to one mile | [75] |
| 214. | Plan of the craters in Volcanello, Lipari Islands | [75] |
| 215. | Section of the strata at the edge of the volcanic vent on the east side of Elie Harbour | [76] |
| 216. | Agglomerate of neck on shore at Ardross, two miles east from Elie | [77] |
| 217. | Ground-plan of volcanic neck, Elie Harbour, showing circular disposition of the stratification | [80] |
| 218. | Section across the great vent of Kincraig, Elie, on a true scale, vertical and horizontal, of six inches to a mile | [81] |
| 219. | Dyke in volcanic neck, on the beach, St. Monans | [82] |
| 220. | Section of part of crater rim, Island of Volcano | [83] |
| 221. | Dyke rising through the agglomerate of a volcanic vent; Kincraig, Elie | [84] |
| 222. | Radiating columnar dyke in the tuff of a volcanic vent. Rock and Spindle, two and a half miles east from St. Andrews | [86] |
| 223. | View of part of the shore front of the great vent at Kincraig, looking westward, with the columnar basalt in front | [88] |
| 224. | Plan of volcanic neck on beach near St. Monans | [89] |
| 225. | Columnar basalt in the neck of Kincraig, Elie, seen from the west | [90] |
| 226. | Section across Largo Law | [91] |
| 227. | Vein of "white-trap" cutting black carbonaceous shales, a little west from St. Monans Church | [92] |
| 228. | Section at Belvedere, S. W. of Exeter | [97] |
| 229. | Diagram to show the unconformability and overlap of the Permian rocks in the Crediton Valley | [97] |
| 230. | Section of the volcanic series at Kellerton, Devonshire | [98] |
| 231. | Section of agglomerate overlain with sandstone and andesite, Posbury, Crediton | [99] |
| 232. | Diagrammatic section across Titterstone Clee Hill | [102] |
| 233. | Dyke on the south-east coast of the Island of Mull | [119] |
| 234. | Fissure left by the weathering out of a dyke | [120] |
| 235. | Plan of basalt-veins with selvages of black basalt-glass, east side of Beinn Tighe, Isle of Eigg | [126] |
| 236. | Arrangement of lines of amygdales in a dyke, Strathmore, Skye | [130] |
| 237. | Systems of joints in the dykes | [132] |
| 238. | Section of cylindrical vein or dyke, cutting the bedded lavas, east side of Fuglö, Faroe Islands | [133] |
| 239. | Joint-structures in the central vitreous portion of the Eskdale Dyke (B. N. Peach) | [133] |
| 240. | Microscopic structure of the vitreous part of the Eskdale Dyke | [136] |
| 241. | Section along the line of the Cleveland Dyke at Cliff Ridge, Guisbrough (G. Barrow), scale, 12 inches to 1 mile | [147] |
| 242. | Section along the course of the Cleveland Dyke, at the head of Lonsdale, Yorkshire (G. Barrow, in the Memoirs of the Geol. Survey, Geology of Cleveland, p. 61) | [148] |
| 243. | Section across the extreme upper limit of Cleveland Dyke, on the scale of 20 feet to one inch (Mr. G. Barrow) | [149] |
| 244. | Upper limit of Cleveland Dyke in quarry near Cockfield (after Mr. Teall) | [149] |
| 245. | Section along the course of the Cleveland Dyke across the Cross Fell escarpment (scale of one inch to one mile) | [150] |
| 246. | Branching portion of the great dyke near Hawick (length about one mile) | [153] |
| 247. | Branching dyke at foot of Glen Artney (length about four miles) | [153] |
| 248. | Basic veins traversing Secondary limestone and sandstone on the coast cliffs, Aidnamurchan | [155] |
| 249. | Section showing the connection of a Dyke with an Intrusive Sheet, Point of Suisnish, Skye | [156] |
| 250. | Section to show the connection of a Dyke with an Intrusive Sheet, Stirlingshire Coal-field | [157] |
| 251. | Intersection of dykes in bedded basalt, Calliach Point, Mull | [158] |
| 252. | Basalt veins traversing bedded dolerites, Kildonan, Eigg | [159] |
| 253. | Ground-plan of intersecting dykes in Lias limestone, Shore, Harrabol, East of Broadford, Skye | [159] |
| 254. | Compound dyke, Market Stance, Broadford, Skye | [162] |
| 255. | Section of coal rendered columnar by intrusive basalt, shore, Saltcoats, Ayrshire | [164] |
| 256. | Dolerite dyke with marginal bands of "white trap," in black shale, Lower Lias, Pabba | [166] |
| 257. | Map of the chief dykes between Lochs Ridden and Striven (C. T. Clough, Geological Survey, Sheet 29) | [170] |
| 258. | Basalt-veins traversing granophyre, St. Kilda | [173] |
| 259. | Section of scoriaceous and prismatic basalt, Camas Tharbernish, north shore of Canna Island | [187] |
| 260. | Banded amygdaloidal basalt showing layers of elongated and steeply inclined vesicles, Macleod's Maidens, Skye | [191] |
| 261. | Termination of basalt-beds, Carsaig, Mull | [193] |
| 262. | Breccia and blocks of mica-schist, quartzite, etc., lying between bedded basalts, Isle of Mull | [197] |
| 263. | Section of Knocklayd, an outlier of the Antrim basalt-plateau lying on Chalk | [202] |
| 264. | Diagram-Section of the Antrim Plateau | [203] |
| 265. | View Of Basalt escarpment, Giant's Causeway, with the Amphitheatre and Chimneys. (From a photograph by Mr. R. Welch) | [207] |
| 266. | Basalt-capping on the top of Ben Iadain, Morven | [209] |
| 266a. | View of the south side of Staffa, showing the bedded and columnar structure of the basalt | [210] |
| 267. | View of Rum from the harbour of Canna | [216] |
| 268. | Section of the cliffs below Compass Hill, Isle of Canna | [218] |
| 269. | Lava cutting out conglomerate and shale. Shore below Canna House | [224] |
| 270. | Section of shales and tuffs, with a coniferous stump lying between two basalt-sheets, Cùl nam Marbh, Canna | [225] |
| 271. | Dùn Mòr, Sanday. (From a photograph by Miss Thom) | [226] |
| 272. | View of the Dùn Beag, Sanday, seen from the south. (From a Photograph by Miss Thom) | [230] |
| 273. | View of Dùn Beag, Sanday, from the north. The island of Rum in the distance. (From a Photograph by Miss Thom) | [231] |
| 274. | Section of eastern front of Dùn Beag | [232] |
| 275. | Enlarged section on the western side of Dùn Beag | [233] |
| 276. | Geological map of the Island of Eigg | [235] |
| 277. | Section of the geological structure of the Island of Eigg | [236] |
| 278. | View of the Scuir of Eigg from the east | [237] |
| 279. | Natural section at the cliff of Bideann Boidheach, north-west end of the Scuir of Eigg | [239] |
| 280. | View of the Scuir of Eigg from the south | [242] |
| 281. | View of the Scuir of Eigg from the south-west of the Loch a Bhealaich, showing the bedded character of the mass | [243] |
| 282. | Section at the base of the Scuir of Eigg (east end) | [244] |
| 283. | Terraced hills of basalt plateau (Macleod's Tables), Skye | [250] |
| 284. | "Macleod's Maidens" and part of basalt cliffs of Skye | [251] |
| 285. | Intercalated group of strata between Basalts, An Ceannaich, western side of Skye | [252] |
| 286. | Escarpment of Plateau-basalts, Cliffs of Talisker, Skye | [253] |
| 287. | Section of the largest of Macleod's Maidens | [254] |
| 288. | Dying out of lava-beds, east side of Sandö, Faroe Isles | [257] |
| 289. | Lenticular lavas, western front of Hestö, Faroe Isles | [257] |
| 290. | Lenticular lavas, east side of Svinö, Faroe Isles | [258] |
| 291. | Section at Frodbonyp, Suderö, Faroe | [258] |
| 292. | Fissure (gjá) in a lava-field, Iceland. (From a photograph by Dr. Tempest Anderson) | [262] |
| 293. | Cones on the great Laki fissure, Iceland. (From a photograph by Dr. Tempest Anderson) | [263] |
| 293a. | Plan of small craters along the line of great Laki fissure, Iceland. (After Mr. Helland, reduced) | [264] |
| 294. | Slemish, a volcanic neck or vent on the Antrim plateau, seen from the north | [272] |
| 295. | Section of volcanic vent at Carnmony Hill (E. Hull) | [272] |
| 296. | Section of the east side of Scawt Hill, near Glenarm | [273] |
| 297. | Section of Neck of basalt, Bendoo, Ballintoy | [273] |
| 298. | Volcanic Neck of dolerite near Cushendall | [274] |
| 299. | Section of Volcanic Neck at 'S Airde Beinne, near Tobermory, Mull | [274] |
| 300. | Interior of the Volcanic Neck of 'S Airde Beinne, near Tobermory, Mull | [275] |
| 301. | Diagram to show the probable relation of the Neck at Carrick-a-raide, Antrim, to an adjacent group of tuffs | [277] |
| 302. | Section of agglomerate Neck at Maclean's Nose, Ardnamurchan | [279] |
| 303. | Diagram to show the probable relations of the rocks on the southern flank of Beinn Dearg Bheag | [282] |
| 304. | Section of Volcanic Vent and connected lavas and tuffs, Scorr, Camas Garbh, Portree Bay, Skye | [284] |
| 305. | Section of the Volcanic Series at Ach na Hannait, south of Portree, Skye | [288] |
| 306. | View of part of a Volcanic Neck at the eastern end of the island of Canna. (From a photograph by Miss Thom) | [289] |
| 307. | Columnar Basalt invading agglomerate of Volcanic Vent, Coroghon Mòr, Isle of Canna. (Height above 20 feet) | [291] |
| 308. | Columnar Basalt invading Volcanic conglomerate, north side of Alman Islet, Canna | [291] |
| 309. | View of neck-like mass of breccia, Brochel, Raasay | [292] |
| 310. | View of Volcanic Neck piercing and overlain by the Plateau-Basalts, Stromö, entrance of Vaagöfjord, Faroe Islands. (From a photograph by Colonel Evans) | [294] |
| 311. | Section of the same Neck as that shown in [Fig. 310] | [295] |
| 312. | Volcanic Neck close to that shown in Figs. [310] and [311] | [296] |
| 313. | Section of wall of another Neck of agglomerate in the same group with those represented in Figs. [310], [311], and [312] | [296] |
| 314. | View of "Segregation-Veins" in a dolerite sill, Portrush, Antrim | [300] |
| 315. | View of Fair Head, from the east, showing the main upper sill and a thinner sheet cropping out along the talus slope | [301] |
| 316. | View of Fair Head from the shore. (From a photograph by Mr. R. Welch) | [302] |
| 317. | Section at Farragandoo cliff, west end of Fair Head, showing the rapid splitting up and dying out of an Intrusive Sheet | [304] |
| 318. | View of the Trotternish Coast, showing the position of the band of Sills | [305] |
| 319. | Columnar Sill intrusive in Jurassic Strata east of Kilmartin, Trotternish, Skye | [306] |
| 320. | View of the northern precipice (500 feet high) of the largest of the Shiant Isles. (From a photograph by Colonel Evans) | [308] |
| 321. | Section of thin Intrusive Sheets and Veins in carbonaceous shales lying among the Plateau-basalts, cliffs north of Ach na Hannait, between Portree Bay and Loch Sligachan | [311] |
| 322. | Upper part of Sill, Moonen Bay, Waternish, Skye, showing the divergence of veins | [313] |
| 323. | Section of the base of the Basalt-plateau with sill and dykes, Sound of Soa, Skye | [314] |
| 324. | Section of Dolerite Sill cut by another sill, both being traversed by dykes, Rudh' an Iasgaich, western side of Sleat, Skye | [316] |
| 325. | Section to show Bedded and Intrusive Sheets, Eigg | [318] |
| 326. | Ground plan of Sills at Ben Hiant, Ardnamurchan | [321] |
| 327. | Section of two Sills in schistose grits, west end of Beinn na h-Urchrach, Ardnamurchan | [322] |
| 328. | Sill traversing bedded Basalts, cliffs of Stromö, at entrance of Vaagöfjord | [323] |
| 329. | View of the same Sill seen from the channel opposite the island of Kolter | [324] |
| 330. | Granulitic and coarsely foliated Gabbro traversed by later veins of felspathic Gabbro, Druim an Eidhne, Cuillin Hills, Skye | [331] |
| 331. | Scuir na Gillean, Cuillin Hills, showing the characteristic craggy forms of the Gabbro. (From a photograph by Mr. Abraham, Keswick) | [335] |
| 332. | Section across Glen Brittle, to show the general relations of the Bedded Basalts and the Gabbros | [336] |
| 333. | View of the crest of the Cuillin Hills, showing the weathering of the Gabbro along its joints and of a compound basic dyke which rises through it. (From a photograph by Mr. Abraham, Keswick) | [338] |
| 334. | Section across the Coire Uaigneich, Skye | [341] |
| 335. | Banded and puckered gabbro, Druim an Eidhne, Glen Sligachan, Skye | [342] |
| 336. | Banded structure in the Gabbro, from the ridge of Druim an Eidhne, between Loch Coruisk and Glen Sligachan | [343] |
| 337. | Banded and doubly folded Gabbro, Druim an Eidhne, 10 feet broad | [345] |
| 338. | Sketch of banded structure in the Gabbros of the hills at the head of Loch Scavaig | [347] |
| 339. | Outline of the hills of the Island of Rum, sketched from near the Isle of Eigg | [350] |
| 340. | View of Allival, Rum, sketched from the base of the north-east side of the cone | [352] |
| 341. | Section of foliated Gabbros in the Tertiary volcanic series of Allival, Rum | [353] |
| 342. | Altered Plateau-Basalts invaded by Gabbro, and with a Dyke of prismatic Basalt cutting both rocks, north slope of Ben Buy, Mull | [357] |
| 343. | Theoretical representation of the structure of one of the Gabbro bosses of the Inner Hebrides | [362] |
| 344. | Section through the Puy de la Goutte and Puy de Chopine | [374] |
| 345. | View of the Huche Pointue and Huche Platte west of Le Pertuis | [376] |
| 346. | View of Glamich, 2537 feet, Glen Sligachan. (From a photograph by R. J. A. Berry, M.D., lent by the Scottish Mountaineering Club) | [380] |
| 347. | Section across the north slope of Beinn an Dubhaich, Skye | [383] |
| 348. | Section from Beinn Dearg to Beinn an Dubhaich, Skye | [385] |
| 349. | Section at north end of Beinn na Cro, Skye | [388] |
| 350. | Ground-plan of basic dyke in Cambrian limestones truncated by granophyre which encloses large blocks of the dyke, Torrin, Skye | [393] |
| 351. | Section on south side of Beinn an Dubhaich, Skye, showing the truncation of a basalt-dyke | [394] |
| 352. | View of the hills on the south side of the head of Loch na Keal, showing the junction of the Granophyre and the bedded basalts | [396] |
| 353. | Section on south side of Cruach Tòrr an Lochain, Mull | [398] |
| 354. | Section at head of Allt na Searmoin, Mull | [398] |
| 355. | Section on south side of Beinn Fhada, Mull | [399] |
| 356. | Section to south of Loch na Dàiridh, Mull | [400] |
| 357. | Section of junction of south side of Loch Ba' Granophyre boss, with the bedded basalts, Mull | [401] |
| 358. | Mass of dark gabbro about two feet in diameter traversed by pale veins of Granophyre, lying on north slope of Creag na h-Iolaire, Mull | [402] |
| 359. | Section at Creag na h-Iolaire, Glen More, Mull, showing basalts and gabbros resting on and pierced by Granophyre | [402] |
| 360. | Section on north side of Orval, Rum | [404] |
| 361. | Junction of Quartz-porphyry (Microgranite) and basic rocks, south-east side of Orval, Rum | [404] |
| 362. | Junction of Granophyre and gabbro, north side of St. Kilda | [410] |
| 363. | Veins of Granophyre traversing gabbro and splitting up into thin threads, north side of St. Kilda | [411] |
| 364. | Pale Granophyre injected into dark basalt, South Bay, St. Kilda | [412] |
| 365. | Veins of Granophyre traversing a fine-grained gabbro and scarcely entering a coarse-grained sheet, west side of Rueval, St. Kilda | [413] |
| 366. | View of sills and veins of pale Granophyre traversing sheets of gabbro, west side of St. Kilda. (From a photograph by Colonel Evans) | [414] |
| 367. | Section of the sea-cliff below Conacher, St. Kilda, showing basic dykes in Granophyre | [417] |
| 368. | Triple basic dyke, sea-cliff, east side of St. Kilda | [417] |
| 369. | Jointed structure of the Granite near the top of Goatfell, Arran. (From a photograph by Mr. W. Douglas, lent by the Scottish Mountaineering Club) | [419] |
| 370. | Intrusive Rhyolite in the lower basalt group of Antrim, Templepatrick | [427] |
| 371. | Section across the southern slope of Carnearny Hill, Antrim | [427] |
| 372. | Section across the Granophyre Sills at Loch a' Mhullaich, above Skulamus, Skye | [433] |
| 373. | Section to show the connection of a sill of Granophyre with its probable funnel of supply, Raasay | [436] |
| 374. | Granophyre sill resting on Lower Lias shales with a dyke of basalt passing laterally into a sill, Suisnish Point, Isle of Raasay | [436] |
| 375. | Weathered surface of spherulitic Granophyre from dyke in banded gabbros, Druim an Eidhne, Meall Dearg, Glen Sligachan, Skye. Natural size | [438] |
| 376. | Plan of portion of the ridge north of Druim an Eidhne, Glen Sligachan, Skye, showing three dykes issuing from a mass of Granophyre | [439] |
| 377. | Weathered surface of spherulitic Granophyre, from dyke in banded gabbros, Druim an Eidhne, Meall Dearg, Glen Sligachan, Skye. Natural size | [440] |
| 378. | Plan of pale Granophyric dyke, with spherulitic and flow-structure, cutting and enclosing dark gabbro, Druim an Eidhne | [441] |
| 379. | Dyke (six to ten feet broad) proceeding from a large body of Granophyre and traversing gabbro, from the same locality as Figs. [375] and [377] | [442] |
| 380. | Section of intruded veins of various acid rocks above River Clachaig, Mull | [443] |
| 381. | Pitchstone vein traversing the bedded basalts, Rudh an Tangairt, Eigg | [445] |
| 382. | Reversed fault on the eastern side of Svinö, Faroe Isles | [454] |
| 383. | Reversed fault on the north-east headland of Sandö, Faroe Isle | [454] |
MAPS
| V. | Map of the Permian volcanic districts of Scotland | [To face p. 106] |
| VI. | Map of the Tertiary volcanic region of the West of Scotland | [To face p. 296] |
| VII. | Map of the Tertiary volcanic district of the North-East of Ireland | [To face p. 446] |
CHAPTER XXIX
THE CARBONIFEROUS VOLCANOES OF ENGLAND
The North of England: Dykes, The Great Whin Sill—The Derbyshire Toadstones—The Isle of Man—East Somerset—Devonshire
1. THE NORTH OF ENGLAND
The volcanic intercalations which diversify the Lower Carboniferous formations of Southern Scotland extend but a short way across the English Border, and although, over the moors and hills of the north of Cumberland and Northumberland, the Carboniferous sandstones, limestones and shales are well exposed, they present no continuation of either the plateau or puy-eruptions which play so prominent a part in the geology of Roxburghshire and Dumfriesshire. This deficiency is all the more noticeable seeing that the Carboniferous system is exposed down to its very base, in the deep dales of the North of England. Had any truly interstratified volcanic material existed in the system there, it could hardly fail to have been detected.
But while contemporaneous volcanic rocks are absent, the northern English counties contain many intrusive masses of dolerite, diabase, andesite or other eruptive rocks, which may be found traversing all the subdivisions of the Carboniferous system. These eruptive materials have taken two forms: in some cases they rise as Dykes, in others they appear as Sills.