Melting of rocks by igneous intrusions, i. 82, 84, 85, 96, 99; ii. 163, 392, 415, 422, 433
Menai Strait, i. 159
Menevian group, i. 114
Merse, volcanic plateau of the, i. 375
Metamorphism of tuffs, i. 157;
of lavas (see under Lavas)
—— by lavas, i. 27;
by sills and bosses, 87, 94, 95, 216, 236, 331, 338, 431; ii. 7, 22, 36, 131, 148, 163, 299, 300, 310, 337, 339, 340, 347, 355, 356, 357, 358, 362, 378, 383, 386, 397, 399, 400, 404, 413
—— in vents, i. 67, 71, 82, 93, 399, 404; ii. 39, 78, 292
—— around vents, i. 72, 349, 350, 352, 399, 404, 432; ii. 76, 272, 273, 276, 280, 292
—— regional, i. 121, 123; ii. 35
Mica, ejected crystals of, in volcanic breccias, ii. 49, 58, 79, 80
Mica-porphyrite, i. 277, 338
Michel Lévy, M., i. 18, 21, 46, 88; ii. 373, 374
Microgranite, i. 131, 215, 235, 249; ii. 367, 437
Microlites of igneous rocks, i. 18, 21, 33; ii. 135, 275
Micropegmatitic structure, i. 20, 418, 449; ii. 5, 368, 437
Microscopic examination of rocks, i. 18, 21
Midlands, eruptive rocks of English, ii. 100
Midlothian, Carboniferous volcanic plateau of, i. 373, 385, 387;
sills of, 446
Miller, Hugh, ii. 237
—— Mr. H., i. 336
Mills, Abraham, ii. 109
Millstone grit, i. 358, 360, 366
Minette, i. 277, 278, 291, 293
Minto Crags, i. 375, 397
Mitchell, Rev. Hugh, i. 301
Moel Siabod, i. 175
—— Wyn, i. 175, 176, 184, 185
Monckton, Mr. H. W., i. 449; ii. 224
Montana, lava-fields of, ii. 115, 267
Montrose, volcanoes of, i. 299
Moray Firth, basin of, i. 271, 343
Morton, Mr. G. H., i. 189
Morven, basalt-plateau of, ii. 208
Mountain-chains, origin of, i. 11, 12, 98
Mourne mountains, granite of, i. 93; ii. 124, 366, 367, 420
Muck, Isle of, ii. 215
Mud-lava, ii. 85
Mudstone, volcanic, i. 423, 436, 440, 444, 466; ii. 86, 222, 258
Mull, branching amygdales of, i. 17;
perlitic glass from, 19;
pale lavas of, ii. 184, 213;
basalt of, 188, 192, 193;
breccias of, 196;
plateau of, i. 24, ii. 208;
non-volcanic breccias in, 196, 211;
flint gravel in, 211;
leaf-beds of, 212;
vents in, 274, 278;
gabbro of, 355;
acid bosses of, i. 20; ii. 395;
acid sills of, 430;
acid dykes and veins of, 443;
enormous denudation of, 457, 461
Murchison, R. I., i. 113, 121, 129, 142, 173, 175, 189, 204, 205, 207, 238, 257; ii. 56, 95
Mynydd-mawr, i. 209, 211, 216
Mythology, influence of earthquakes and volcanoes on, i. 2

Nant Francon, i. 161
Naples, puys of, i. 100, 429
Napoleonite, i. 22
Necker, L. A., ii. 112, 123, 139, 140, 146
Necks, volcanic, i. 56;
of fragmentary materials, 56;
of non-volcanic detritus, 57, 289, 343, 426;
of agglomerate, 58; ii. 276;
internal stratification in, i. 63; ii. 80, 294;
with central lava-plug, i. 64, 430;
with dykes and veins, 66, 430; ii, 291;
of lava-form material, i. 67, 430; ii. 271;
parasitic, i. 69;
connection of, with cones, 70, 435; ii, 70, 89, 277, 281, 290;
metamorphism of, i. 67, 71, 82, 93, 399; ii. 39, 78;
metamorphism of rocks around, i. 72, 349, 350, 352, 399, 404, 432; ii. 76, 272, 273, 274, 276, 280, 292;
inward dip of rocks towards, i. 73, 352; ii. 80;
connection of, with bosses, i. 93; ii. 276, 284;
entombment and exposure of, i. 434;
connection of with valleys, 272, 366, 375; ii. 61, 65;
relation between their size and the character of the agglomerate, 76;
connection of, with sheets of tuff or lava, 70, 89, 277, 284
—— Silurian, i. 215, 235;
Old Red Sandstone, 277, 288, 293, 311, 318, 323, 328;
Carboniferous, 394, 399, 400, 404, 406, 424, 465; ii. 13, 28, 47;
Permian, ii. 62, 67;
Tertiary, ii. 202, 270, 276
Neptunist and Plutonist controversy, i. 363; ii. 67, 95, 110, 112
New Mexico, necks in, i. 68
Newry granite, i. 290
Nicholson, Prof. Alleyne, i. 228, 229
Nicol, James, i. 311, 369
—— W., ii. 238
Nigrine, ii. 79
Nithsdale, Permian volcanic rocks of, ii. 58, 60, 62, 65
Nodular structure of lavas, i. 20, 162, 204, 206, 207, 211, 232, 247, 255, 274, 346
Nolan, Mr. J., i. 240, 251, 315; ii. 423, 424, 425
Non-volcanic debris, among volcanic rocks, i. 31, 57, 289, 313, 345, 381, 399, 402, 422, 426, 437; ii. 18, 27, 28, 58, 64, 76, 78, 99, 195, 196, 281, 423;
indicates comparatively feeble eruptions, i. 57, 289, 345, 426, 438; ii. 293;
points to earliest eruptions of a vent, ii. 76
Nordenskjöld, Mr. O., i. 120
North Berwick Law, i. 371, 373, 403
North, Mr. Barker, ii. 244
Norway, eruptive rocks of, i. 28
Nuneaton, i. 171

Obsidian, i. 18, 19; ii. 370
Ochil Hills, i. 274, 276, 277, 279, 281, 286, 287, 288, 293, 303, 308, 311
Oil-shales of the Lothians, i. 361, 362, 462
O'Kelly, J., i. 349; ii. 49
Oldham, T., ii. 299
Old Red Sandstone, lines of vents in, i. 69;
granite protrusions of, 236, 272, 277, 290, 337;
of County Waterford, 251;
distribution in Britain, 257;
an exceptional stratigraphical type, 258;
conditions of its deposit, 259, 263, 297;
original scenery of, 265;
vegetation of, 265;
isolation of the water-basins of, shown by fossil evidence, 265;
classification of, 260;
history of the investigation of, 268;
volcanic centres in, 271;
nature of volcanic products in, 273;
structure of lavas and tuffs of, 281;
volcanoes of, 259, 263, 294, 303, 323, 325, 337, 341, 343, 346, 348, 352;
subdivisions of, 297;
thickest conglomerates of, 301;
composition of conglomerates of, 302, 315, 341;
unconformabilities in, 267, 328, 333;
Upper division of, 348, 375, 383; ii. 42
Olenellus-zone, i. 112, 130, 132, 140, 144
Olenus-zone, i. 144
Olivine, i. 154, 418, 420; ii. 58, 135
Omagh, i. 315
Ophitic structure, i. 21, 417; ii. 136, 184, 274
—— type of dolerite, i. 418, 421
Oregon, crater lake in, i. 58
Orkney Isles, i. 271, 344, 350; ii. 121
Orthoclase, ejected crystals of, ii. 79
Orthophyre, i. 273, 276, 277, 308
Osann, A., ii. 191
Oyenhausen, C. von, ii. 112, 280, 333, 340, 367, 372, 381

Palæopicrite, i. 261
Palæozoic systems, i. 139;
volcanic rocks resemble modern, i. 30
Palagonite, i. 33, 61, 151, 180, 246, 422, 423; ii. 44, 46, 57, 223
Paradoxides-zone, i. 144
Paramorphism, i. 249
Peach, Mr. B. N., i. 114, 128, 147, 168, 191, 192, 195, 196, 197, 198, 199, 200, 216, 240, 277-294, 307, 308, 329, 331, 344, 345, 369, 375, 425, 426, 476; ii. 133, 145
Pebidian, i. 145
Pegmatite, i. 20, 119, 127, 418, 449; ii. 5, 368, 437
Pembrokeshire, volcanic rocks of, i. 145, 159, 205
Penmaen-mawr, i. 209, 215
Pennant, T., ii. 109
Pennine chain, ii. 8
Pentland Hills, volcanic series of the, i. 102, 269, 273, 276, 279, 281, 285, 287, 289, 291, 311, 317
Perlite, i. 130
Perlitic structure, i. 19, 196, 199, 206, 211, 216, 232, 274
Permian system, geographical conditions accompanying the deposition of, ii. 53, 97;
subdivisions of, in S. W. England, 94;
volcanic phenomena of, i. 46; ii. 55;
lavas and tuffs of, 57, 58;
vents of, 62, 67, 70, 96;
sills of, 91, 100
Permo-carboniferous strata, ii. 54
Petersen, Dr., i. 275, 336
Phillips, J., i. 133, 170, 205, 238; ii. 3
—— J. A., i. 260, 261
—— W., i. 171; ii. 95
Phonolite, i. 380 (analysis); ii. 375
Phyllite, i. 162, 222
Picrite, i. 377, 417, 420, 448, 450; ii. 57
—— type, i. 418
Pillow-structure in lavas, i. 26, 184, 193, 201, 240, 244, 252; ii. 189, 259
Pitchstone, i. 18, 19, 130; ii. 134, 174, 204, 238, 242, 246, 370, 437, 444
Plagioclase, ejected crystals of, ii. 79
Plants fossil, in tuffs, i. 392; ii. 113, 198, 212, 222
Platania, G., i. 26
Plateau-type of volcanoes, i. 42, 100, 308, 341, 364
Plateaux, Carboniferous, of Scotland, i. 364;
distribution of, 367;
composition of, 377;
structure of, 383;
lavas and tuffs of, 383;
vents of, 394;
dykes and sills of, 406;
close of eruption of, 410;
Tertiary, ii. 181;
formation of modern Icelandic, 265
Player, Mr. J. H., analyses by, i. 377, 381; ii. 138, 330
Playfair, John, i. 363; ii. 110
Plinthite, ii. 197
Pliocene (supposed) of Lough Neagh, ii. 449
Plutonic operations of volcanoes, i. 77;
granite, 88
Plutonists and Neptunists, i. 363; ii. 67, 95, 110, 112
Pomeroy, volcanic series near, i. 315
Porphyrite, i. 190, 193, 207, 229, 240, 252, 273, 274, 377, 379
Porphyritic structure, i. 19, 274; ii. 128
Portlock, J. E., ii. 110, 111, 113, 199, 201, 299, 364
Portraine, conglomerates at, i. 244
Portrush, shells in supposed basalt at, ii. 110, 299
Potstone, i. 125
Pre-Cambrian rocks, i. 111, 121, 126
Pressure, experimental proof of effects of, i. 24
Prestwich, Sir J., ii. 103
Propylites, ii. 185, 388
Proterobase, i. 247
Pterygotus, i. 265
Pumice in tuffs, i. 244, 422; ii. 17, 27, 28, 32, 44, 46, 286, 288;
in volcanic necks, i. 60, 180; ii. 17, 39, 195
Pumiceous structure, i. 15, 33, 34, 60
Puys, as a type of volcano, i. 10, 44, 100, 414;
probable subærial nature of some, 432;
Carboniferous, 308, 364, 414, 424, 463; ii. 13, 28, 34, 47;
Permian, ii. 62;
Tertiary, 271, 276
Puy de Chopine, i. 32; ii. 374
—— Dôme, ii. 373
—— Montchar, i. 32
—— Pariou, i. 66, 70; ii. 31, 281
Pyroclastic detritus, i. 31, 58, 61
Pyromeride, i. 211
Pyrope, ii. 58, 79
Pyroxene, ii. 135

Quartz-porphyry, i. 19, 156, 159, 160, 161, 165, 277, 291, 314; ii. 96, 369, 420, 423, 430, 431
Quartz-trachyte, ii. 371
Quartzite, i. 112, 170

Raasay, basalt of, ii. 192;
neck-like breccias in, 293;
acid sill of, 430
Raddling or red-staining of rocks, i. 250, 261
Radiolarian cherts, i. 123, 167, 169, 173, 174, 184, 196, 201, 244
Rain-pittings in strata, i. 342
Raisin, Miss, i. 161, 163, 164, 165, 210
Ramsay, A. C., i. 126, 142, 143, 144, 145, 158, 159, 168, 175, 176, 177, 178, 179, 180, 182, 183, 204, 205, 208, 210, 212, 214, 223, 237, 364
Ratho type of dolerite, i. 418, 421
Red Head, section at, i. 300
Red Hills, Skye, scenery of, i. 105; ii. 379
Reed, Mr. Cowper, i. 205
Reid, Mr. Clement, ii. 449, 450
Renard, Prof. A., i. 148, 149
Renfrewshire, Carboniferous volcanic rocks of, i. 368, 385, 397, 400, 404, 408, 416, 430, 447