Browsing by Author "Sinclair, William John, 1877-1935."
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Item Eocene and Oligocene of the Wind River and Bighorn basins. Bulletin of the AMNH ; v. 30, article 7.(New York : Published by order of the Trustees, American Museum of Natural History, 1911) Sinclair, William John, 1877-1935.; Granger, Walter, 1872-1941.Item A new fossil crocodilian from the Paleocene of New Mexico. American Museum novitates ; no. 1189(New York City : The American Museum of Natural History, 1942) Mook, Charles Craig, 1887-1966.; Granger, Walter, 1872-1941.; Sinclair, William John, 1877-1935.; Olsen, George, d. 1939.Item Notes on the Tertiary deposits of the Bighorn Basin. Bulletin of the AMNH ; v. 31, article 5.(New York : Published by order of the Trustees, American Museum of Natural History, 1912) Sinclair, William John, 1877-1935.; Granger, Walter, 1872-1941."1. The Lower Eocene sediments of the Bighorn Basin represent the alluvial filling of an intermontane trough of downwarp. 2. They have been transported from the surrounding mountains as shown by the lithology of the gravels, sands and clays. No volcanic ash occurs. 3. They are stream transported and have been deposited in stream channels or spread over flood plains. No evidence in favor of wind transportation has been observed. 4. The Eocene clays are banded in more or less regular alternation, red and blue. This may be due to climatic causes leading to concentration of iron salts and their oxidation. 5. The beds are divisible into three formations, the Knight, Lysite and Lost Cabin, readily separable by their fossils, but not differing lithologically and conformable throughout. The Wind River (comprising the Lysite and Lost Cabin) is confined to the southwest portion of the basin (McCulloch Peak possibly excepted) and has been removed elsewhere by erosion. 6. The Lower Eocene formations are overlain conformably by another set of beds, containing much lignite, the Tatman Formation, in which determinable vertebrate fossils have not yet been found. Invertebrate fossils suggest that it may be of Eocene age, possibly Bridger. 7. The Tatman Formation is overlain by andesitic gravels of doubtful age, of which but a remnant on the top of Tatman Mountain is preserved in place. 8. Deformative stresses have acted on the basin filling after the deposition of the Tatman formation, flexing it into marginal anticlines and synclines and increasing the centripetal dip of the beds. 9. The major dissection of the basin is, probably, a comparatively late event, geologically speaking, perhaps referable, in part, to the Pleistocene"--P. 66-67.Item On the names of Lower Eocene faunal horizons of Wyoming and New Mexico. Bulletin of the AMNH ; v. 33, article 15.(New York : Published by order of the Trustees, American Museum of Natural History, 1914) Granger, Walter, 1872-1941.; Sinclair, William John, 1877-1935.Item Paleocene deposits of the San Juan Basin, New Mexico. Bulletin of the AMNH ; v. 33, article 22.(New York : Published by order of the Trustees, American Museum of Natural History, 1914) Sinclair, William John, 1877-1935.; Granger, Walter, 1872-1941."The more important stratigraphic results may be summarized as follows: 1. Separation of the pre-Puerco beds into several members which are, in descending order, a heavy conglomeratic sandstone with much fossil wood, a series of clays with channel sandstones, a conglomerate and a series of dove-colored clays, red-banded near the top. The two conglomeratic members have disconformities at their bases. Dinosaurs occur, especially at two levels separated by the lower conglomerate. More or less of this series of beds may be correlateable with the Animas formation. 2. Complete confirmation of Barnum Brown's observation regarding the unconformable relationship of the Puerco with respect to the conglomeratic sandstone with fossil logs on which it rests. A topography in low relief was developed on the surface of this sandstone previous to the deposition of the Puerco clays, which cover up these hills and valleys. 3. Accurate location of the two Puerco fossil levels and demonstration of the fact that Polymastodon is confined to the uppermost of the two levels. For their position see sections A and B, Fig. 2. 4. Measurement of the thickness of the Puerco on continuous exposures from the unconformity at its base to the level of the first occurrence of Torrejon fossils. 5. Discovery of fossil plants in the Puerco. 6. Accumulation of data which seem to prove the fluviatile origin of the Puerco sediments. 7. Discovery of a new fossil horizon in the Torrejon, 100 feet below the horizon from which fossils had hitherto been obtained. 8. Finding of Torrejon fossils at still lower levels (see sections). 9. Location of the Torrejon levels with reference to those of the Puerco (see actions A and B, Fig. 2). 10. Correlation of the Rio Puerco and Arroyo Torrejon sections published by Dr. Gardner of the U.S. Geological Survey with the sections measured by the American Museum party. 11. Accumulation of data which seem to prove the fluviatile origin of the Torrejon sediments"--P. 314-315.Item A revision of the bunodont Artiodactyla of the Middle and Lower Eocene of North America. Bulletin of the AMNH ; v. 33, article 21.(New York : Published by order of the Trustees, American Museum of Natural History, 1914) Sinclair, William John, 1877-1935.Item Volcanic ash in the Bridger beds of Wyoming. Bulletin of the AMNH ; v. 22, article 15.(New York : Published by order of the Trustees, American Museum of Natural History, 1906) Sinclair, William John, 1877-1935.; Granger, Walter, 1872-1941.Item The Washakie, a volcanic ash formation. Bulletin of the AMNH ; v. 26, article 4.(New York : Published by order of the Trustees, American Museum of Natural History, 1909) Sinclair, William John, 1877-1935.; Granger, Walter, 1872-1941."The difference in petrographic character between the Bridger and Washakie has an important bearing on the problem of correlation in time. The Bridger rocks are rhyolite tuffs containing glassy sanidine while the Washakie rocks are andesitic with soda-lime feldspar. From the absence of agglomerates and the fine-grained character of much of the ash it seems probable that it was transported mainly by the wind, and as the prevailing winds are at present from the west and had probably the same direction in Tertiary time, the centers of eruption should be located somewhere in the west or southwest. The absence of agglomerates does not favor the idea of local contemporaneous vents discharging rhyolitic and andesitic ash respectively and the great thickness and uniform petrographic character of each formation is opposed to the conception of rapid variation in the chemical composition of the ash at a single center of eruption. Assuming contemporaneous deposition from two centers of eruption it seems probable, in view of the comparatively short distance separating the areas occupied by the two formations (about 50 miles)¹ that some intermixture of the two types of ash should be found, but the conspicuous absence of plagioclase feldspar from all the Bridger tuffs and its presence in all those of the Washakie shows that this has not occurred. The lithologic evidence, therefore, does not favor the idea of contemporaneity for any part of the Bridger or Washakie. The faunistic evidence of contemporaneity of the lower Washakie and Upper Bridger is therefore in contradiction to the lithological evidence. ¹Estimate based on map of Fourth Parallel Survey"--P. 26-27.