The Deseado Formation of Patagonia

The material described and the conclusions drawn in the following pages are the results of the Amherst Expedition to Patagonia in 1911; an expedition organized and sent out by t...

The locality worked by the Amherst party is situated about three miles east of the Chico River, just across the line of the homestead of D. J. Venter as plotted on the Plano de...

The exposure of the Deseado, which the Amherst party worked, yielded 293 specimens, each presumably representing an individual. (There were besides these a few that were indeter...

The systematic arrangement of the South American ungulates is of such a nature that scarcely two students of these forms have agreed. I feel that the Pyrotheridae are proboscide...

In the Deseado beds this group of running and hopping animals is well represented, making about 14% of the Amherst collection, and varying in size from a little larger than a ra...

The teeth are simple, with but a shallow external furrow near the anterior margin of the premolars and molar. A film of cement covers each tooth and extends to the top of the cr...

The toxodonts of the Deseado are much more varied than those of the Santa Cruz, and less so than those of the Casamayor; the teeth less hypsodont than in the Santa Cruz, and mor...

This family was established to include a group of large, heavily built ungulates, not unlike rhinoceroses in form, which have rooted teeth, the molars being similar to those of...

This family is characterized by the teeth being hypsodont, the second upper incisor and the third lower incisor being enlarged into caniniform teeth, the upper molars complicate...

by the incisors, canine and premolar 1 all being of subequal size, by all the teeth being brachydont, and by the crescents of the lower premolars and molars being modified. On t...

The forms making up the _Homalodontotheria_ are characterized by a dentition which is clearly a derivative of that of _Toxodontia_, but is distinguished by the teeth being brach...

This group is composed of large, long limbed creatures, with a highly specialized dentition, in which the canines of the upper jaw are developed into great curved tushes, resemb...

This suborder was established by Ameghino to receive the peculiar genus _Pyrotherium_ and related forms. These animals are of large size, massive build, with narrow elongated sk...

While all of small size, numerically the rodents make about a third of our collection, the number of genera and species being, however, relatively small. All are hystricomorphs...

The scarcity of edentates in the Deseado beds is in striking contrast to their abundance in the Santa Cruz formation. Whereas in this latter horizon over half of the finds are e...

In our collection, the marsupials are represented, unfortunately, by but a few specimens; though this Deseado fauna included, as is shown by the fragmentary remains, a wide rang...

In the Deseado beds, birds occur in small numbers, Ameghino having described four species. The remains are generally found as isolated bones, and it is hard to associate the sep...