452 INDEX. 
Diabase, Olivine-free, Characteristics of, 61-66. 
———, Color of, 62, 63. 
—— —, Constituents of, 63. 
ae , augite, 63. 
-—----—— , Magnetite, 63. 
——— , plagioclase, 63. 
—— — of Copper Creek 67, 254. 
—— — — Eagle River Section, 66, 67, 170. 
———— Fond du Lac mine, 67, 251. 
——~-—, Frequency of, 65, 66. 
———, Localities for, 65. 
———, Modes of occurrence of, 62. 
——— of Montreal River, 67, 68, 227. 
———, Pseudamygdaloidal, alteration in, 63, 64. 
———, Pseudomorphism in, 64. 65. 
———, Pumpelly’s description of, 61-66. 
——-—, Tabulation of observations of, 66-68. 
———, Texture of, 63. 
—— —, Types of, 61. 
——— of Union mine, 67, 219. 
Diabase Orthoclase-free, (coarse-grained). See Gabbro, 
Orthoclase-free. 
Diabase-porphyrite and ashbed-diabase, 77-87. 
——, Amygdaloids of, 79. 
——near Baptism River, 85, 326, 440. 
——, Base of, 78, 79. 
—— of Beaver Bay, 84, 305. 
—— —— River, 83, 308. 
——— Bohemian Range, 81, 183, 
——— Cascade River, 85, 295. 
——, Characteristics of, 77. 
——, Color of, 77, 78. 
——, Constituents of, 78-80. 
———-—, apatite, 79. 
————, calcite, 79. 
———~—, chlorite, 79. 
———— , epidote, 79. 
———~—, oligoclase, 78, 79. 
—— ——, orthoclase, 78, 79. 
———-— silica content, 79, 440, 442. 
——, Copper in, 422. 
——, Distribution of, 155. 
—— of Duluth, 80, 83, 275-277. 
——— Eagle River, 171-173. 
——— Encampment Bluff, 84, 285. 
——— French River, 83. 
——near Great Palisades, 84, 316, 442. 
——, Grain and texture of, 77. 
—— of Knife River, 84, 279. 
—— — Lester River, 279, 280. 
——— Little Carp River, 82, 215, 217. 
——, Localities for, 80. 
— — of Michipicoten Island, 85, 87, 344-346. 
——— Porcupine Mountains, 82, 215-220, 440. 
——— Portage Bay Island, 85, 296-298. 
——— Potato River, 83, 231. 
——— Red Rock Bay, 85, 323. 
— —, Relations of, to ashbed-diabase, 78. 
————— olivine-diabase, 78. 
—-—---—— orthoclase-gabbro and quartzless porphyry, 79. 
——near Split Rock River, 84, 301, 303. 
—— of Suffolk mine, 81, 176, 177. 
——, Tabulation of observations on, 83-87. 
Diallage. See Augite. 
Dieffenbach, O., Publication of, 19. 
Dikes, 143, 144. 
Dikes of Agate Bay Group, 287, 293, 294. 
— of Animikie Group, 144, 367, 368, 372, 373. 
—— Basic Rocks, 143. 
—— Beaver Bay Group, 299, 306, 307, 320-323. 
—— Big Trout Bay, 371, 372. 
—— Black and Nipigon Bays, 334. 
—— Chester Creek, 278. 
—— Duluth Group, 278. 
—— Grand Portage Bay, 367. 
—— Hat Point, 368. 
—, Huronian, 389. 
—of Kaministiquia River, 374. 
—— Lester River Group, 283. 
— — Mamainse, 143. 
—— Minnesota Coast, 143, 278, 283, 294, 301, 306, 307, 320-323, 
829, 384. 
—— Pigeon Bay, 372, 373. 
—— Pigeon Point, 370. 
—— Pigeon River, 371. 
— — Porcupine Mountains, 223. 
—— Red Rock Bay, 322, 323. 
—— Saint Louis River, 384. 
—— Silver Islet, 378. 
~—— Silver Islet Landing, 379. 
—— Split Rock River, 301. 
—— Temperance River Group, 329. 
'—— Thunder Bay, 370. 
—— Thunder Cape, 376. 
—— Victoria Islands, 372. 
—— Wauswaugoning Bay, 368, 369. 
Diorites, 393, 400. 
Dog Lake, Schists of, 396. 
Doré River, Huronian Rocks of, 401. 
Douglas, J., Paper by, 21. 
Douglas County Copper Range, 250-259. 
———— on Aminicon and Middle Rivers, 255-257. 
———— in Bayfield County, 257, 258. 
———w—on Black River, 251-255. 
or Copper Creek, 254, 255. 
————, Copper of, 251, 428. 
———-—, Lower Division on, 159. 
———~—, Relation of, to Keweenaw Series, 251. 
————, sandstone of, Age of, 259. 
———_— , Western sandstone on, 259, 366. 
Douglas Houghton River, Eastern Sandstone on, 185, 355, 356. 
——-—, Wadsworth on rocks of, 255, 363. 
Duluth, Diabase-porphyrite of, 80, 83, 275-247. 
—, Granitic porphyry of, 116, 119, 263, 270-272, 435. 
— Orthoclase-gabbro of, 51, 53, 55, 269. 
— Orthoclase-free gabbro of, 44, 46, 277. 
—, Quartzless porphyry of, 95. 
—, Western Sandstone absent at, 412. 
Duluth Group, 155, 275-279. 
——, Absence of copper from, 426. 
— —, Characteristics of, 266. 
—— on Chester Creek, 275. 
——, Dikes of, 278. é 
——at Eastern end of Minnesota coast, 294. 
——, Origin of rocks of, 277. 
——. See Duluth. 
Dupes, J. A., Publication of, 18. 
Dutton, T. R., Publication of 15. 
Eagle Harbor, 413. 
——, Sandstone of, 128. 
——, Topography at, 17%. 
Eagle Mountain, Granitic porphyry of, 116, 124, 145, 273, 274 
ae 
