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Alaska Algonkian andesite anticlinal argillite basal basin beds belt Big Bad lands boulders California Cambrian canyon Carboniferous Chouteau clays cliff coal Colorado conglomerate creek Cretaceous crystalline deposits Devonian diabase dike east erosion fault fauna feet feldspar fold formation forms fossils Geol glacial glacier gneiss granite gravel hills igneous inches Inyo county Iowa kilometer Kinderhook Koyukuk lake Lewis range limestone Livingston range looking Lower Maryland meters miles Missouri moraine mount mountain Muir glacier Negatives in United northern occur Paleozoic Patuxent peak peneplain Pennsylvania Photographed plain plate Potomac quarry quartz quartzite railway region Report ridge river rocks sand sandstone schists sediments shales shore showing Silurian Siyeh slope South Dakota southwest Spirifer strata stratigraphic stream structure summit surface Survey of Pennsylvania syncline terrace Tertiary thickness thrust tion U. S. Geological Survey unconformably United States Geological Upper valley Virgilina Virginia volcanic Yellowstone York
Seite 499 - In 1873 he was appointed geologist and botanist to Her Majesty's North American Boundary Commission, which had been constituted to fix the boundary line between British North America and the United States, from the Lake of the Woods to the Rocky mountains, and which had been carrying on its labours for about a year.
Seite 527 - 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.
Seite 504 - Preliminary report on the geology of the Bow and Belly River region, Northwest Territory, with special reference to the coal deposits.
Seite 376 - Virgilina district. 3. The rocks are pre-Cambrian in age and represent an area of ancient volcanics similar to others described as occurring along the Atlantic Coast region from eastern Canada to Georgia and Alabama and in the Lake Superior region. 4. The rocks are cut by numerous approximately parallel quartz veins which contain workable copper deposits. The veins have been described as true fissure veins, and the ore is glance and bornite, without chalcopyrite and pyrite.
Seite 117 - Not merely the earth's crust, but the whole of earth-knowledge is the subject of our research. To know all that can be known about our planet, this, and nothing less than this, is its aim and scope. From the morphological side geology inquires, not only into the existing form and structure of the earth, but also into the series of successive morphological states through which it has passed in a long and changeful development. Our science inquires also into the distribution of the earth in time and...
Seite 376 - ... as indicated in the prevailing schistose structure, and the large development of the secondary minerals, chlorite, epidote and hornblende ; and smaller amounts of others. The alteration has advanced sufficiently far in the more schistose phase to destroy, in most cases, the original structure and minerals of the rock. 2. From structural, petrographic and chemical evidence, it is shown that the rocks are derived from an original andesite. The altered andesite is intimately associated with the...
Seite 499 - ... should be — scientific facts being clearly and succinctly stated and the conclusions logically drawn. The main geological result arrived at was the examination and description of a section over 800 miles in length across the central region of the continent, which had been previously touched upon at a few points only, and in the vicinity of which a space of over 300 miles in longitude had remained even geographically unknown.
Seite 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...
Seite 376 - Watson states his conclusions'' as follows : "1. The rocks of the area here described have been greatly altered through pressure and chemical metamorphism, as indicated in the prevailing secondary schistose structure and the abundant development of the secondary minerals — chlorite, epidote, and hornblende — and small amounts of others. The alteration has advanced sufficiently far in the schistose phases to destroy in most cases the original structure and minerals of the rock. "2. From structural,...
Seite 357 - Types of copper deposits of the Southern United States," and in it gave the first detailed account of the geology of the district. Weed, so far as the writer is aware, was the first to recognize the true character of the rocks in which the deposits occur. He says, in this connection :c •'The rocks are all of igneous origin — even the softest and most shaly show this character in thin sections under the microscope. But in a few instances only, is the igneous nature of the schists recognizable...