PALEOCENE PRIMATES OF THE FORT UNION, WITH DIS- 

 CUSSION OF RELATIONSHIPS OF EOCENE PRIMATES. 



By James Williams Gidley, 



Assistant Curator, United States National Museum. 



INTRODUCTION. 



The first important contribution to the knowledge of Fort Union 

 mammalian life was furnished by Dr. Earl Douglass and was based 

 on a small lot of fragmentary material collected by him in the au- 

 tumn of 1901 from a locality in Sweet Grass County, Montana, about 

 25 miles northeast of Bigtimber.* The fauna described by Douglass 

 indicated a horizon about equivalent in age to the Torrejon of New 

 Mexico, but the presence of unfamilar forms, suggesting a different 

 faunal phase, was recognized. 



A few years later (1908 to 1911) this region was much more fully 

 explored for fossil remains by parties of the United States Geological 

 Survey and the United States National Museum. Working under 

 the direction of Dr. T. W. Stanton, Mr. Albert C. Silberling, an ener- 

 getic and successful collector, procured the first specimens in the 

 winter and spring of 1908, continuing operations intermittently 

 through the following years until the early spring of 1911. The 

 present writer visited the field in 1908 and again in 1909, securing a 

 considerable amount of good material. The net result of this com- 

 bined field work is the splendid collection now in the National 

 Museum, consisting of about 1,000 specimens, for the most part 

 upper and lower jaw portions carrying teeth in varying numbers, 

 but including also several characteristic foot and limb bones. 



Although nearly 10 years have passed since the last of this collec- 

 tion was received, it was not until late in the summer of 1920 that 

 the preparation of the material for study was completed. This task 

 was especially tedious and difficult owing to the small size and exceed- 

 ingly fragile condition of most of the specimens, it being necessary 



1 Douglass, Proc. Amer. Philos. Soc, vol. 41, No. 170, 1902, pp. 216-224, pi. 29 ; Annals Carnegie Mus., 

 vol. 5, No. 2, 1908, pp. 11-26, pis. 1, 2. 



No. 2469.— PROCEEDtNGS U. S. NATIONAL MUSEUM, VOL. 63, ART. I. 



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