. The age of mammals in Europe, Asia and North America. Mammals, Fossil; Paleontology. EOCENE DEPOSITS. VOLCANIC ERUPTIVE AREAS IN THE SAME REGIOM Fig. 23. — [To left] Chief Eocene fossil-mammal-bearing Formations (larjicly volcanic tuffs) in the Mountain Region of North America, and [to right] areas of \()lcanic rock (lavas) in the same geographic region. 1. Puerco and Torrejon, N. Mex. 2. Wasatch, Utah and Wyo. 3. Big Horn (Wasatch), Wyo. 4. Wind River, Wyo. 5. Huerfano, Col. 6. Bridgcr, Wyo. 7. Washakie, Wyo. 8. Uinta, Utah and Col. 9. (?) Fort Union, Mont. Oligocene deposits of the John Da
. The age of mammals in Europe, Asia and North America. Mammals, Fossil; Paleontology. EOCENE DEPOSITS. VOLCANIC ERUPTIVE AREAS IN THE SAME REGIOM Fig. 23. — [To left] Chief Eocene fossil-mammal-bearing Formations (larjicly volcanic tuffs) in the Mountain Region of North America, and [to right] areas of \()lcanic rock (lavas) in the same geographic region. 1. Puerco and Torrejon, N. Mex. 2. Wasatch, Utah and Wyo. 3. Big Horn (Wasatch), Wyo. 4. Wind River, Wyo. 5. Huerfano, Col. 6. Bridgcr, Wyo. 7. Washakie, Wyo. 8. Uinta, Utah and Col. 9. (?) Fort Union, Mont. Oligocene deposits of the John Day Basin, the next important step was the recognition by Sinclair - (1906) that the deposits of the Bridger Basin (Middle Eocene) were also chiefly of volcanic nature, or tuffs. The same author ' in 1907 proved that the successive Washakie Basin deposits were likewise of ash. This led to a thorough examination by the United States Geological Survey through Albert Johannsen of samples of rock from the entire Eocene Series, with the most interesting and conclusive results.^ The manner of deposition of the volcanic ash in these various basins, ' Merriam, J. C, A Contribution to the Geology of the John Day Basin. Univ. Cal., Bidl. Dept. GeoL, Vol. II, 1901, p. 26!). 'Sinclair, W. J., Volcanic Ash in the Bridger Beds of Wyoming. Bull. Amer. Mas. Nat. Hist., Vol. XXII, Art. xv, 1906, pp. 273-280. ?'Sinclair, W. J., Science, Vol. XXVII, no. 685, Feb. 14, 1908, p. 254. ?* Johannsen, .\lbert, in lilteris, Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Osborn, Henry Fairfield, 1857-1935. New York, The Macmillan Company
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectpaleontology, bookyea
