ii. 59, 98

Sandwich Islands, lava-cones of, i. 10 Sanidine ejected from volcanic vents, ii. 58, 79 Sanquhar, Silurian volcanic rocks at, i. 192, 195, 199; Permian volcanic rocks at, ii. 62 Santorin, ii. 134 Saponite, ii. 79 Scenery, origin of, i. 8, 100 Schalstein, i. 262; ii. 36 Schists, primeval, i. 110, 114, 118, 119; produced by deformation of igneous rocks, 75, 114, 118, 119, 121, 162, 240, 249, 252, 261 Schmidt, Dr. C. W., ii. 266 Scoriaceous structure, i. 15, 16, 282, 327, 339 Scorpions, fossil, i. 174, 356, 466 Scotland, lines of fault in, i. 11; Vesuvian cones of, 42; plateaux of, 43; puys of, 46; submarine lavas of, 48; Carboniferous vents of, 55; volcanic scenery of, 104; pre-Cambrian rocks of, 111; Cambrian rocks of, 112; Lewisian gneiss of, 114; Dalradian rocks of, 121; Arenig rocks of, 123, 191; Old Red Sandstone of, 266, 273, 281, 291; Carboniferous geography of, 356; Carboniferous volcanoes of, 359; Carboniferous plateaux of, 367; Carboniferous puys of, 414; Permian volcanoes of, ii. 55; Tertiary dykes of, 122; Tertiary basalt-plateaux of, 208, 274, 304; Tertiary gabbros of, 327; Tertiary acid rocks of, 379 Scrope, G. P., i. 27, 82, 45, 116; ii. 373, 374, 381 Sedgwick, A., i. 142, 166, 175, 218, 227, 257; ii. 1, 2, 3, 5, 113, 139, 153, 157 Segregation (_see_ Differentiation) Segregation-veins, i. 84, 92; ii. 66, 130, 300, 303 Selwyn, Mr. A. C. R., i. 143, 175, 208, 221 Semi-opal, ii. 79 Sepulchre Mountain, i. 79 Serpentine, i. 195, 293 Shale, alteration of, i. 72, 451; ii. 164 Shap, granite of, i. 236, 238, 271, 290 Sheets, intrusive (_see_ Sills) Shelve, i. 176, 190 Shetland, i. 271, 289, 292, 293, 345 Shiant Isles, ii. 307 Shineton Shales, i. 144 Shore-lines, traces of ancient, i. 295, 305 Shropshire, ancient volcanic rocks of, i. 129, 189; latest eruptive rocks of, ii. 101 Sicily, i. 26 Sidlaw Hills, i. 286, 294, 303 Sills, vitreous margins of, i. 18; tectonic relations of, 77, 83, 451; origin of name, 83; differentiation (segregation) in, 81, 450; ii. 476; ordinary stratigraphical position of, i. 85; considered as parts of incompleted volcanoes, 86; metamorphism by, 87, 94, 451; ii. 299, 303, 310; conditions for injection of, i. 97, 98, 99, 458; columnar structure of, ii. 187, 291, 301, 306, 308, 319; amygdaloidal structure in, 299, 312; banding of, 309; split by later sills, 310, 316; extreme subdivision of, 311; slaggy surface in some, 312; give off veins, 313; double and multiple, 318, 434; connection with vents, 322 ---- pre-Cambrian, i. 118, 124; Cambrian, 155, 170, 171; Silurian, 187, 195, 206, 216, 237, 249; Devonian, 261; Old Red Sandstone, 277, 291, 321, 335, 343, 345; Carboniferous, 408, 446, 472; ii. 2, 21, 30, 48; Permian, 64, 66; of Midlands, 102, 103; Tertiary, (1) Basic, 298; (2) Acid, 366, 430 Silurian system, i. 173; vegetation of, 174; geography of, 263; volcanoes of, 175; classification of, 175; two volcanic series of, 177 ---- volcanoes in Shropshire, i. 189; in Scotland, 191; at Builth, 203; in Pembrokeshire, 205; in Caernarvonshire, 207; in the Berwyn Hills, 218; in Anglesey, 219; in the Lake District, 227; in Gloucestershire, 238; in Ireland, 239, 254 Skae, H. M., i. 294, 299, 306, 375; ii. 57 Skiddaw, i. 228; granite of, 236 ---- Slate, i. 229 Skomer Island, i. 207 Skye, spherulitic dykes and sills of, i. 20; ophitic structure from, 20; basalt-terraces of, 24; metamorphism by granophyre of, 95, 96; volcanic scenery of, 103, 105; dykes of, ii. 123, 124, 129, 139, 140, 146, 150, 152, 154, 160, 162, 164, 165, 173, 269; bedded basalts of, 192, 249, 269; tuffs of, 251; connection of dykes and superficial lavas in, 269; vents in, 280; sills of, 304; gabbro bosses of, i. 116; ii. 334; acid bosses of, 379; acid sills of, 431; acid dykes of, 437; pitchstone veins of, 445; subsidence of, 447 Slaggy structure, i. 16, 33, 59, 282, 327, 339; ii. 98, 187 Slane, volcanic rocks near, i. 244 Slate-tuffs, i. 180, 213, 234 Slemish a volcanic neck, ii. 271 Slieve Foye, ii. 421 ---- Gallion, ii. 200 ---- Gullion, ii. 422 Small Isles, basalt-plateau of, ii. 215; vents of, 288; sills of, 318; acid bosses of, 403; acid sills of, 431 Small, Mr. E. W., i. 207 Smaragdite found in volcanic vents, i. 62 Snowdon, volcanic rocks of, i. 20, 42, 47, 102, 175, 208, 209, 210, 211, 212, 213, 218, 226 Soda-felsites, i. 183, 196, 247 Solfataric action, i. 71; ii. 185, 205, 388 Sollas, Prof., i. 96; ii. 175, 293, 415, 421, 422 Solway, Carboniferous volcanic plateau of, i. 375, 385, 413 Somerset, volcanic rocks of, ii. 32 Somma, denudation of, i. 3, 100 Spheroidal structure of dolerite, i. 456 Spherulitic structure, i. 19, 20, 95, 120, 130, 155, 162, 184, 211, 232, 235, 346; ii. 369, 381, 392, 432, 435, 437, 441, 446 Spilosite, i. 262 Springs, mineral, connected with volcanic action, i. 390, 445 St. Abb's Head, i. 338 Staffa, i. 25; first notice of, ii. 109; columnar basalts of, 186, 188, 210; basalt conglomerate of, 195 Staffordshire, latest eruptive rocks of, ii. 101, 103 St. Andrews, old volcanoes near, ii. 71, 73, 87 St. David's, Cambrian volcanic rocks of, i. 145 ---- Head, i. 205 Steam in volcanic action, i. 13, 15, 16, 71 Stecher, Dr., i. 421, 451; ii. 165 St. Kilda, dykes of, ii. 173, 416; gabbro of, 358; general account of geology of, 405; granophyre of, 408 Stocks, or bosses, i. 78, 88 Strahan, Mr. A., i. 171; ii. 10, 12, 23, 28, 32 Strathaird, ii. 123, 140, 164, 269 Strathbogie, i. 344; ii. 121 Strathmore, i. 304 Stromboli, i. 4 Sublimations, traces of ancient, i. 445 Submarine eruptions, i. 48 Sub-ophitic structure, i. 417 Subsidence and volcanic action, i. 295, 297, 444, 463; ii. 42, 205, 447, 470 Subterranean igneous injections, i. 77 (_see_ Bosses, Dykes, Sills) Suess, Prof. E., ii. 474 Sun-cracks, i. 342 Sweden, Archæan volcanic rocks of, i. 120 Syenite, ii. 366 Symes, Mr. R. G., i. 311, 343, 369; ii. 201, 428

Tate, G., ii. 3, 113 ---- R., ii. 204 Tatlock, Mr. R. R., i. 273, 278 Tawney, E. B., i. 157 Teall, Mr. J. J. H., i. 90, 114, 116, 117, 118, 119, 120, 156, 192, 194, 200, 207, 210, 275, 277, 290, 311, 336, 338, 346, 407, 449; ii. 2, 3, 5, 7, 11, 32, 44, 113, 131, 134, 135, 137, 138, 140, 144, 149, 292, 293, 329, 367, 368, 369 Teesdale, i. 228 Termier, M. P., ii. 375 Terrestrial volcanic eruptions, i. 50 Tertiary Volcanic Series, ii. 181 Subaerial character of eruptions, ii. 103, 198 Scenery of, ii. 255, 256, 349, 391, 405, 408 The Plateaux, ii. 183, 249; lavas of, 183, 218, 236, 256; thickness of individual sheets, 192, 206, 254, 257; lenticular character of lavas of, 193, 257; greatest depth of, 210, 211, 213, 260; tuffs and clays of, 194, 202, 204, 211, 222, 225, 251, 258, 277, 284, 287; non-volcanic fragments in, 196, 211, 213, 219; lignites of, 198, 203, 208, 213, 251; gravels and conglomerates of, 198, 212, 238, 256; coal of, 213, 251, 256, 287; leaf-beds of, 204, 212, 222, 225, 288; carbonaceous nature of the upper parts of intercalated sediments in, 223, 226, 227, 229, 232, 251, 288; evidence for intervals between the eruptions in, 203, 205, 208, 221, 228, 240, 245, 251, 254, 288; no evidence of great central vents in, 208, 214, 255, 258, 260, 267; faulted condition of, 200, 208, 209, 452; subsidences of, 205, 208, 209, 214, 447; ancient river channels of, 217, 228, 231, 234, 456; volcanic cones of, 202, 218, 230, 277, 281, 285; paralleled by the modern Icelandic eruptions, 260; vents of, 202, 218, 230, 270, 276 The Basic sills, ii. 298, 304 The Gabbro bosses, ii. 327, 349, 355, 358; history of the gabbro intrusions, 359 The Acid rocks, ii. 364; petrography of, 366; history of their investigation, 371; analogies with trachytes of Central France, 373; intruded at base of the gabbros or of the bedded basalts, 337, 353, 357, 431, 432, 444; bosses of Skye, 378; of Mull, 395; of Small Isles, 405; of St. Kilda, 405; of Arran, 418; of Carlingford, 420; of Slieve Foye, and Barnavave, 421; of Slieve Gullion, 422; of Antrim, 426; acid sills, 430; acid dykes and veins, 437 Metamorphism of the basalts, ii. 272, 276, 337, 339, 340, 347, 355, 356, 357, 358, 362, 378, 383, 386, 397, 399, 400, 404, 413 Texture, varieties of, in igneous rocks, i. 78, 449; ii. 5, 299, 360 Tholeiites, ii. 137, 158 Tholeiite type of basalt, i. 419, 421 Thornhill, volcanic rocks of, ii. 60 Thoroddsen, Th., ii. 261, 262, 263, 264, 265, 266, 278 Thrust-planes, i. 229 Time in geological history, ii. 107, 461, 465 Timmins, J. H., i. 133 Tinto, i. 278, 288, 329 Titterstone Clee Hill, ii. 101 Toadstones of Derbyshire, i. 359; ii. 8 Topley, W., i. 147; ii. 3, 5, 7 Torridonian rocks, i. 111, 112, 113, 120; ii. 350 Tortworth, volcanic rocks at, i. 238 Tourmakeady, volcanic rocks of Bala age at, i. 251 Townson, R., i. 363 Trachyte, i. 183, 230, 246, 273, 276 (analysis), 379 (analysis), 386, 403, 407, 421; ii. 36, 47, 96, 138, 152, 184, 236 Traill, Mr. W., ii. 175, 421, 422 Traprain Law, i. 372, 380, 403, 405 Traquair, Dr. R. H., i. 266 Tremadoc group, i. 144, 177 Trevelyan, W. C., ii. 3 Triassic eruptive rocks, i. 29; geography, ii. 108 Trichites, i. 19; ii. 136 Troctolite, ii. 332 Tuffs, i. 31; association of, 33; composition of, 34; alternations of, 34, 61; blending of, with non-volcanic sediment, 35, 437; fossiliferous, 36; without lava, 36; necks of, 58; relation of, to lavas, 61; metamorphism of, ii. 224 ---- pre-Cambrian, i, 125, 135; Cambrian, 147, 151, 155, 163, 165, 167; Silurian, 178, 189, 190, 195, 205, 209, 212, 213, 222, 224, 229, 232, 241, 245, 246, 254, 255; Devonian, 262; Old Red Sandstone, 279, 281, 289, 337, 339, 351; Carboniferous, 381, 384, 387, 399, 422, 427, 429, 432, 436, 466;