ii. 124, 125, 126, 129, 130, 139, 144, 146, 160, 162, 163, 164, 174,

185, 189, 190, 223, 224, 247, 269, 281, 284, 285, 309, 310, 318, 320, 334, 339, 347, 348, 368, 382, 384, 385, 387, 389, 392, 407, 408, 409, 413, 415, 433, 434, 437, 441, 446 Harkness, R., i. 228; ii. 56 Harlech anticline, i. 159, 179, 187; group, 176 Hatch, Dr. F. H., i. 183, 184, 187, 188, 229, 230, 246, 247, 248, 249, 261, 277, 278, 306, 377, 380, 381, 417, 419, 420; ii. 57, 96, 184, 274, 276, 299, 319, 332, 367, 368, 369, 370, 388, 398 Haughton, Prof. S., i. 346; ii. 422 Hawaii, lava-fountains of, i. 12; differentiation in lavas of, 27; lava-cauldron of, 58 Haworth, Mr. E., ii. 96 Hay Cunningham, R. I., i. 269, 317, 363, 372, 373, 449, 451; ii. 237, 238, 244 Heaphy, Mr. C., i. 432 Hebrides, basalt-sheets of, i. 24, 47, 52, 102; acid rocks of, 95, 102; gabbros of, 84, 90, 102; scenery of, 105; pre-Cambrian rocks of, 112, 114, 117, 121; Cambrian land of, 141; early observations on the Tertiary volcanic rocks of, ii. 109, 110, 111; dykes of, 118, 146, 158, 174; basalts of, 181, 186, 215; pitchstone lava of, 238, 246; plateau-scenery of, 249; Tertiary rivers and lakes of, 217, 228, 231, 234, 252; vents of, 274; basic sills of, 304; gabbro intrusions of, 327; acid intrusions of, 364, 379, 430, 437; dislocations of, 452; denudation of, 455 Heddle, Dr., i. 274, 302; ii. 78, 79, 246, 307, 406 Helland, Prof. A., ii. 191, 261, 263, 264 Henderson, Mr. J., i. 449 Henry Mountains, laccolites of, i. 86; ii. 362 Henslow, J. S., ii. 22, 224 Heterogeneity in volcanic magmas, i. 85, 90; ii, 190, 334 Hett Dyke, ii. 1, 7, 147 Hibbert, S., i. 46 Hicks, Dr. H., i. 126, 145, 154, 158, 159, 166, 206 Hill, Mr. J. B., ii. 140 Hill, Rev. E., i. 135 Hinde, Dr. G. J., i. 198; ii. 35 Hinxman, Mr. L., i. 114, 344; ii. 121 Hobson, Mr. B., i. 260; ii. 23, 27, 96, 99 Holden, Mr. J. S., ii. 204 Holl, H. B., i. 133, 134, 170 Holland, Mr. P., i. 177, 178, 179; ii. 23 Hollybush Sandstone, i. 133, 170 Holocrystalline structure, i. 78; ii. 136, 184 Hopkins, W., ii. 177, 179, 268 Hornblende, ejected crystals of, i. 178, 181; ii. 49, 51, 58, 79 Hornblende-schists formed from basic igneous rocks, i. 75, 114, 118, 119, 124, 129 Horne, Mr. John, i. 114, 196, 199, 200, 344, 345, 375; ii. 23, 144, 292 Hornito of a lava-stream, i. 55; ii. 264 Hornstone, i. 131, 136, 277, 278 (analyses), 324 Houston Marls, i. 423, 436, 440, 444, 466 Howard, Mr. H. T., i. 207 Howell, Mr. H. H., i. 294, 307, 364 Hoy, Island of, i. 350 Hughes, Prof. T. M'K., i. 126, 144, 160, 161, 166, 168, 220, 222, 223, 227 Hull, Mr. E., ii. 42, 95, 103, 272, 421, 426, 449 Hurlet Limestone, i. 360, 366, 394, 410, 415, 444, 452, 456, 467, 470, 474 Huronian rocks, i. 111 Hutchings, Mr. W. M., i. 227, 230, 233 Hutton, James, i. 363; ii. 9, 110 Hutton, W., ii. 3 Hyperite, i. 279 Hysgeir, pitchstone of, ii. 246

Iceland, Tertiary basalts of, ii. 182, 260; Tertiary gabbros and liparites or granophyres of, 261; continuity of volcanic phenomenon of, 261; lava-fields of, i. 24, 42, 53, 100; ii. 260; lava-domes of, i. 10; ii. 265; fissures of, i. 70; ii. 262, 271, 454; dykes of, 122, 261; cinder cones of, 264, 271; subsidence of, 447 Idaho, lava-fields of, ii. 267 Iddings, Prof., i. 28, 29, 30, 78, 79, 82, 84, 90; ii. 128, 178 Idiomorphic crystals, i. 21, 417, 420; ii. 40 Index Limestone of the Scottish coal-fields, i. 360, 444, 452 India, fissure-eruptions of, i. 10; volcanic plateau of, ii. 180 Intermediate volcanic rocks, silica-percentage of, i. 14 Intersertal structure, i. 417; ii. 136 Intrusive rooks, defined, i. 14; occasional cellular character of, 16; flow-structure in, 22, 161; varieties of, 77; textures of, 78, 449; ii. 274, 360, 392; in sheets, sills, and laccolites, i. 83; melting of rocks by, 82, 84; ii. 129, 163, 392; consolidation of, i. 84; banding of, 84, 450; ii. 329, 342; heterogeneity of, i. 85; ii. 344; metamorphism by, i. 94, 451; influence of surrounding rocks on, 95; conditions of their intrusion, 97; columnar structure in, ii. 187, 291, 301 ---- Pre-Cambrian, i. 116; Cambrian, 156; Silurian, 187, 195, 206, 216, 235, 237, 248, 249; Devonian, 261; Old Red Sandstone, 277, 291, 321, 335, 338, 343, 345; Carboniferous, 406, 408, 420, 446; ii. 1, 21, 30, 33, 40, 48; Permian, 58, 64; Tertiary, 270, 298 Ireland, submarine eruptions of, i. 48; Dalradian rocks of, 122, 123, 126; Arenig rocks in, 123; Silurian volcanic rocks of, 239, 251; granites of, 290; Old Red Sandstone volcanic rocks of, 346, 348; Carboniferous volcanic rocks of, 359; ii. 37; early observers among the Tertiary volcanic rooks of, 109; Tertiary basalt plateau of, 364, 370, 371; gabbros of, 359; acid rocks of, 420 Iron-ore, pisolitic (Arenig), i. 181, 208; Tertiary, of Antrim, ii. 204 Irvine, Mr. D. R., i. 294, 299 Irving, Rev. A., ii. 95 Isogeotherms, shifting of, i. 98 Italy, old volcanoes of, i. 4; ii. 474, 477

Jack, Mr. R. L., i. 294, 308, 369, 375, 396, 404; ii. 57, 145 Jameson, Robert, i. 268, 269, 317, 363; ii. 109, 161, 244, 333, 355, 364 Jan Mayen, ii. 182 Jedburgh type of dolerite and basalt, i. 418 Jennings, Mr. C. V., i. 176, 177, 179, 180, 181, 184, 185, 186, 187, 188 Johnston-Lavis, Dr., ii. 261 Joints in dykes, ii. 132 Judd, Prof. J. W., i. 157, 275; ii. 115, 116, 134, 137, 162, 185, 209, 211, 245, 247, 267, 274, 278, 280, 303, 307, 309, 315, 316, 319, 322, 328, 329, 332, 333, 349, 356, 360, 372, 388, 410, 439 Jukes, J. B., i. 143, 171, 175, 208, 218, 219, 245, 246, 250, 254, 316;