2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I3I 



of this age. Misunderstandings in the past as to the characteristics and, 

 in some instances, the age of related types, largely from inadequate 

 original descriptions of forms in these two ungulate groups, early 

 confused the picture and resulted in incorrect identifications and evi- 

 dently misleading conclusions as to the horizon represented by the 

 Badwater assemblage. It is hoped that the present review and revision 

 will clarify the record and render more useful the information to be 

 derived from this occurrence. 



ACKNOWLEDGMENTS 



I am particularly indebted to Dr. G. Edward Lewis of the U. S. 

 Geological Survey for relinquishing to me for restudy this very inter- 

 esting assemblage, and assuring me that no embarrassment would 

 ensue. I wish also to acknowledge the helpful information furnished 

 me by Harry A. Tourtelot both in the office and in the field. Tourtelot, 

 obligingly and with contagious enthusiasm, showed me the more sig- 

 nificant and likely collecting sites during our 1946 field exploration. 



Investigation was immeasurably aided by my being permitted to 

 examine and study related materials in universities and other museums, 

 and by the loan of pertinent specimens in these collections for direct 

 comparison. Acknowledgment is particularly due Dr. J. LeRoy Kay at 

 the Carnegie Museum, Dr. Glenn L. Jepsen at Princeton University, 

 Dr. George G. Simpson at the American Museum, and Dr. Joseph T. 

 Gregory at Yale Peabody Museum. Dr. H. E. Wood, II, aided in 

 furnishing information on materials in the original Badwater col- 

 lection. 



The exquisite pencil drawings depicting selected materials shown in 

 plates 1-3 were prepared by Lawrence B. Isham, staff artist for the 

 Department of Geology in the U. S. National Museum. Mr. Isham 

 also prepared the chart showing the tapiroid sequence. 



HISTORY OF INVESTIGATION 



Discovery of upper Eocene vertebrate materials in the Badwater 

 area was made by Wood, Seton, and Hares, as reported by them in 

 1936. Moreover, this would appear to be the first record for the oc- 

 currence of upper Eocene on the north side of the Wind River Basin. 

 Recognized by Wood, Seton, and Hares were Ainynodon advcnus, 

 Tchnatherium, cf. cidtridcns, and a crocodile. Collections later (1942) 

 secured by J. D. Love and G. E. Lewis from Lysite Mountain to the 

 north of Badwater Creek, for Yale University, include remains iden- 

 tified by Lewis as TelmatJierium, cf, cultridens, and an indeterminate 



