EXTINCT VERTEBRATE FAUNA OF THE BRIDGER TERTIARY 

 FORMATION OF WYOMING TERRITORY. 



INTRODUCTION. 



The following pages contain a description of fossil remains of vertebrated 

 animals collected in the vicinity of Fort Bridger, a military post situated in 

 the southwest corner of Wyoming Territory. 



Many of the specimens were obtained during Professor Hayden's geological 

 explorations of 1869 and 1870, but the greater part of them were collected 

 during the same years and the succeeding one by Dr. James Van A. Carter, 

 residing at Fort Bridger, and by Dr. Joseph K. Corson, United States Army, 

 the surgeon of the post. These gentlemen have diligently explored a wide 

 extent of country in their immediate neighborhood in the search for fossils 

 with the most intelligent interest. The results of their explorations they 

 have liberally placed at the service of naturalists by voluntarily donating 

 all the more characteristic portions of their collections to the Academy of 

 Natural Sciences of Philadelphia.* 



After the present work was supposed to be nearly ready for the press, and 

 the accompanying plates from I to XXII were complete, the last summer, the 

 writer received a pressing invitation from his friend Dr. Carter to visit him 

 at Fort Bridger. As the invitation was accompanied with liberal facilities 

 and offers of aid in exploration, the author availed himself of the opportunity 

 of visiting a region of so much interest, and accordingly spent the summer 

 vacation in a trip to the locality. 



Fort Bridger occupies a situation in the midst of a wide plain at the base of 

 the Uintah Mountains, and at an altitude of nearly seven thousand feet above 

 the ocean-level. The neighboring country, extending from the Uintah and 

 Wahsatch Mountains on the south and west to the Wind River Range on the 

 northeast, at the close of the Cretaceous epoch, appears to have been occupied 



* Iu speaking of this institution hereafter I shall briefly refer to it as the Academy, 

 or the Academy of Philadelphia. 



