Page:Popular Science Monthly Volume 67.djvu/573

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EXPLORATIONS FOR FOSSIL VERTEBRATES.
567

A third American Museum party was in the heart of the Laramie plains of Wyoming, where in 1898 the ruins of a sheep herder's cabin composed entirely of dinosaur bones led to the discovery of an extraordinarily rich deposit of the great amphibious dinosaurs and other reptiles of the Upper Jurassic age, which is roughly estimated as 6,000,000 years distant. The museum has been working in this same quarry six years, and each year has taken out a very large freight carload, yet the deposit is still far from being exhausted.

Stratified Deposits in the Bridger Basin, Southwestern Wyoming.

A fourth expedition was in southwest Wyoming, just north of the Uintah Mountains, nor far from the once famous Fort Bridger, a now deserted army post. This middle eocene flood plain or lake basin dates back about 2,500,000 years in its fauna, which embraces small ancestors of the horses, about the size of a whippet hound, a great variety of monkeys, hundreds of small quadrupeds remotely related to the tapirs, including one especially large type. Also of the great Uintatherium or Uinta beast, a very archaic type of quadruped, the discovery of which between 1870 and 1873 aroused widespread interest in this country. The museum party was very fortunate also in this region and brought back remains of about five hundred individuals. In this collection were one hundred and twenty-one turtles, chiefly found by Dr. O. P. Hay, both river and land forms, some ancient, some surprisingly modern in type, including species which are now only represented in South America.

During the summer of 1904 three expeditions went out from the