Report of Progress in the Geological Resurvey of the Cripple Creek District, ColoradoU.S. Government Printing Office, 1904 - 36 sider |
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amount anticline Baculites Bearpaw shales Belly River Birdsville blende bluff bodies breccia calcite Canadian Palæont carbonate cent Claggett formation clay coal bank Cochran Mills Company Conemaugh Cope Cow Creek Cretaceous Crooked Creek crystals deposits depth described dike district Elders Ridge quadrangle exposed farm fault planes fauna feet thick field fluorite fluorspar fossils galena Genevieve limestone genus Geological Survey Girty Hill horizon Illinois inches thick Judith River beds Karbers Ridge Kittanning coal known Laramie lignite Louis limestone Lower Freeport material mile east Milk River minerals mines Missouri Montana mouth northeast occurs outcrop Pittsburg Pittsburg coal Plum Creek Pope County portion present probably region Rept Roaring Run Rosiclare Run anticline sand sandstone seam shaft shows spar species specimens strata sulphides surface syncline teeth thin U. S. Geol Upper Freeport coal Valley Vanport vein vicinity West Lebanon zinc
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Side 54 - Ashbaugh analysis shows next the highest amount of combustible matter of any locality in the field. The coal of the Ewing bank in all the different benches is slaty and poor. Some of it is overloaded with iron pyrites, and none of it in its raw state could be considered marketable fuel, except for local supply. Although not the lowest in total amount of combustible matter, it is the lowest in fuel ratio, and carries so high a percentage of sulphur as to make it unsalable for many purposes.
Side 26 - ... its fauna rather than separate successive epochs of time in the geological period which is represented by the whole great group. The proof of the identity of these widely separated portions of the Laramie group consists in the recognition of various species of fossil mollusks in all of them that are found in some one or more of the others, thus connecting the whole by faunal continuity. Similar proof has. also been obtained by Professor Cope in the discovery of certain species of vertebrate fossils...
Side 24 - Tertiary" — here and in previous announcements designated as the Belly River series — must be relegated to a position below the Pierre shales, or at least to one below an upper portion of these shales. The beds thus separated as the Belly River series, were, in 1875, by me correlated with the Judith River series of the Missouri.^ Additional and extensive collections of fossils since obtained, and now being worked out, confirm and strengthen this correlation, and lead to the presumption that the...
Side 68 - X 4. are the extremities of low ridges, which are arranged nearly at right angles to a wide longitudinal elevated half of the osseous base. They are separated by shallow grooves from each other and are not continuous with the basis just mentioned, which rises abruptly above them. They are smooth. The ‘handle' above alluded to is triangular in section having two bevels on the side supporting the tooth ridges.
Side 101 - When considered in its entirety, the vertebrate fauna of these beds is remarkably similar to, though distinctly more primitive than, that of the Laramie. Almost or quite all of the Laramie types of vertebrates are present, though, as a rule, they are represented by smaller and more primitive forms. The similarity between this fauna and that of the Laramie contrasts strongly with the great dissimilarity between the vertebrates of the Judith River and those of the Atlantosaurus beds, the next older...
Side 67 - The association of the minerals and the common phenomena of marked silicification of the hanging wall are interpreted as indicating deposition from heated ascending solutions carrying fluosilicates of zinc, lead, copper, iron, barium, and calcium. These are believed to have been broken up and precipitated by descending cold waters, which possibly also furnished the sulphur to combine with the metals, though it is not improbable that sulphur was an original constituent of the rising solutions.
Side 32 - Walls," which are composed of a basis strata upon which the estuary deposits of the "Bad Lands" of the Judith rest, which are doubtless of the age of Cretaceous formation No. 1, or upper Jurassic. - In the above description there are some errors relating to the geography, such as the statement that Musselshell River rises near the Judith Mountains; and the sandstones ("Stone Walls" of Lewis and Clarke) upon which, according to Hayden's statement, the estuary deposits of this region rest, were erroneously...
Side 11 - ... Niobrara, and as there is no evidence of an erosion interval or unconformity, it is probably represented by shales or sandstones. The paleontologic indications are that in this region the Niobrara is represented by dark shales not separable stratigraphically from the Benton. If this be true the Benton shales of the upper Missouri represent more than the formation known by the same name in Nebraska, in Colorado east of the Front Range, and at other places, and really include the whole of the Colorado...
Side 22 - A subtype comprises lodes in which the sheeted zone follows "basalt" or phonolite dikes. 2. Irregular bodies adjacent to fissures and formed by replacement and recrystallization of the country rock — usually granite. These types are not always sharply distinct, but may be connected by deposits of intermediate character. All the ore bodies, of whatever type, exhibit certain common features which serve to distinguish the deposits of Cripple Creek from those of most other mining districts. In the...
Side 21 - ORES. 21 sphalerite occur in small quantities in many of the mines, but rarely contain enough of the precious metals to form ore. Native gold appears to be absent from the telluride ores, except as it may be set free by the oxidation of these tellurides. The usual gangue minerals of the ores are quartz, fluorite, and dolomite. Roscoelite and rhodochrosite are also found in places. Celestite, or sulphate of strontium, while never present in large amount, frequently occurs as little acicular crystals...