Bulletin of the Geological Society of America, Volume 13The Society, 1902 - Geology Vols. 1-44 include Proceedings of the annual meeting, 1889-1933, later published separately. |
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Common terms and phrases
Alaska Algonkian Anaktoovuk andesite anticline argillite arkonensis Arundel basin beds belt boulders calcareous California canyon Carboniferous clays cliff coast Colorado conglomerate coral layer creek Cretaceous crystalline rocks deposits Devonian east elevation Encrinal limestone erosion exposed fault fauna feet feldspar fold formation fossils Geol geologists glacial glacier gneiss granite gravel Hall hills horizon igneous inches Inyo county Iowa kilometer Koyukuk lake Lewis range limestone Livingston range loess lower Maryland meters miles moraine Mount mountains mucronatus Negatives in United Newark northern occurs Paleozoic Parahyba Patapsco Patuxent Pennsylvania Pernambuco Photographed plain plate plateau Potomac quarry quartz quartzite railway range region Report river sand sandstone schists seam sediments shales Silurian slope species specimens Spirifer station strata stratigraphic stream structure surface terrane Tertiary Thedford thickness tion U. S. Geological Survey unconformably United States Geological Upper valley Virgilina Virginia York
Popular passages
Page 525 - The Auditing Committee reported that the accounts of the Treasurer had been found correct, and the Society adopted the report. The Council submitted its report on the matter of the proper pronunciation of the name " Cordilleran," which had been referred to the Council at the Washington meeting, 1899.
Page 293 - The outlet of the valley is 624 feet above lake Superior, according to the railway levels, though only 7 miles in a straight line from the shore, and there is a fall of 126 feet in less than 300 yards to Talbot lake, which represents the general level of the neighboring valleys. The Helen Mine valley is a narrow trough, three-quarters of a mile long and less than a quarter of a mile wide, running about east and west and opening northwest toward lake Talbot. The walls of the valley rise steeply to...
Page 7 - ... copper range. The north slope of this ridge is abrupt, and its summit is 100 to 300 feet above the plain. The plain is underlain by the Lake Superior sandstone in horizontal beds, and the ridge consists of lava flows dipping steeply toward the south. The sandstone in general is not firmly cemented and is easily eroded, while the traps or lava flows are much more resistant to erosion. The abrupt northward slope of the trap ridge functions as a fault scarp, although by this statement it is not...
Page 119 - INVESTIGATIONS To one of the nestore of American geology, the immortal William B. Rogers, we owe the first description of the Kanawha black flint of West Virginia. In his " Fourth Annual Report of Progress '' of the Geological Survey of Virginia for the year 1839 he gives such a full and minute description of this remarkable stratum that little has been added by any subsequent observer. He did not define its exact place in the stratigraphic column, but by making it the dividing line between what...
Page 353 - The strata are occasionally disrupted by dikes; about half a mile from the Gillis, and dipping eastward to it, is a dike bearing N. 20 E., containing abundant sprigs and grains of disseminated native copper. Epidote occurs both in the trap rock and in the quartz, and in the slate strata near the dike, which seems to indicate that the trappean rock is of the...
Page 322 - ... beds. They are named the Kintla formation from their occurrence in mountains on the 49th parallel, northeast of Upper Kintla lake. They also form conspicuous peaks west of Little Kootna creek. The Kintla formation closely resembles the Grinnell, and represents a recurrence of conditions favorable to deposition of extremely muddy, ferruginous sediment. The presence of casts of salt crystals is apparently significant • of aridity, as the red character is of subaerial oxidation.
Page 358 - At a subsequent date, when the rocks were brought near the surface, they were further changed by weathering. The mineral products resulting from the alteration are strongly in evidence. Epidotization and chloritization are manifested on a considerable scale. The greenstones are cut in several places by diabase dikes of later geological age. One of these dikes, 12 feet wide, is exposed in the Blue Wing mine at the 100-foot level, where it is observed to cut across the schistosity of the rocks. These...
Page 122 - Freeport coal and its associated strata from the Pennsylvania line along their eastern outcrops across to the Kanawha valley. In this I was entirely successful, and the result is a complete confirmation of my original conclusion with reference to the horizon of the Upper Freeport coal on the Great Kanawha, namely, that it is the first one below the black-flint stratum, and hence this latter member belongs near the base of the...
Page 315 - Walcott's columnar section of the terrane is that given in Col. 9, of Table VIII. . In 1902 Willis stated in the following words his correlation of the Lewis series as exposed in the Clarke and Lewis ranges: ' The oldest formation of the series, the Altyn limestone, is assigned to the Algonkian period on the basis of fossils discovered by Weller in its characteristic occurrence at the foot of Appekunny mountain near Altyn, Montana. These fossils are fragments of very thin shells of crustaceans [chiefly...
Page 253 - Alaskan ranges lie outside the region under discussion and will not be further considered. The so-called Coast Range extends from near the boundary of Washington northward through British Columbia into southeastern Alaska. In British Columbia it has a width of about 100 miles, which decreases to the northward. Its peaks vary in altitude from 7,000 to 8,000 feet. Following the coast line for nearly 000 miles.