NO. 8 UPPER EOCENE ARTIODACTYLA — GAZIN 3 



study type and certain other specimens of upper Eocene artiodactyls. 

 It was also thus possible to make direct comparisons and correctly 

 identify the rather large collection of Uinta C artiodactyls in the 

 U. S. National Museum. 



Through the courtesy of Dr. Joseph T. Gregory the Uinta artiodac- 

 tyls described by Marsh were made available. Drs. George G. Simpson 

 and Edwin H. Colbert kindly permitted me to study various specimens 

 in the American Museum collections described by Osborn, Granger, 

 Scott, and Wortman. Materials described by Scott, or by Scott and 

 Osborn, as well as more recently acquired collections at Princeton 

 University were turned over to me for this investigation by Dr. 

 Glenn L. Jepsen. Pertinent materials in the large upper Eocene col- 

 lections at the Carnegie Museum were lent through the kindness 

 of Dr. J. LeRoy Kay, these being essentially the specimens studied by 

 Peterson. 



The photographs used in plates 1-3, 6-7, and 13-18 were made 

 through the kindness of Dr. G. Arthur Cooper, with a background 

 overlay prepared by William D. Crockett. Those in plates 4, 5, and 

 8-12 were made by the photographic laboratory of the Smithsonian 

 Institution. Charts i and 2 were prepared by Lawrence B. Isham, staff 

 artist for the department of geology. Acknowledgment is also due the 

 Committee on "Nomenclature and Correlation of the North American 

 Continental Tertiary" of the Society of Vertebrate Paleontology for 

 use of terms and composition of ages and subages of the Eocene 

 employed in the charts. These are to be defined in the committee's 

 forthcoming report. 



HISTORY OF INVESTIGATION 



Undoubtedly the earliest exploratory work in the upper Eocene of 

 North America was Marsh's trip of 1870, which resulted in the dis- 

 covery of fossil remains in the now well-known Uinta formation in 

 northeastern Utah. Marsh gave the name Uinta Basin to this area 

 of Eocene deposition, and from it the designation Uinta was subse- 

 quently applied to the beds that, overlying the Green River forma- 

 tion, are well exposed throughout the basin. Materials from here, 

 collected by Marsh in 1870 and by his parties in following years, par- 

 ticularly 1874 and 1877, included the Artiodactyla that he referred to 

 by the generic names Eomeryx, Parameryx, and Oromeryx in a 

 lecture delivered and published in 1877. Inasmuch as the descrip- 

 tions were inadequate, without figures, and no types were designated, 

 the names were invalid. However, in 1894 he described and figured 

 species of each, adding Hyomeryx to the list. 



