PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



SMITHSONIAN INSTITUTION 



U. S. NATIONAL MUSEUM 



Vol. 83 Washington : 1935 No. 2981 



NEW PALEOCENE MAMMALS FROM THE FORT UNION 



OF MONTANA 



By George Gaylord Simpson 



American Museum of Natural History, New York City 



In 1901, Earl Douglass, working for Princeton University, dis- 

 covered and collected mammal remains in the Fort Union Group east 

 of the Crazy Mountains in central Montana, and Princeton expedi- 

 tions under Dr. M. S. Farr also made small collections in 1902 and 

 1903. A. C. SiJberUng, now of Harlowton, Mont., accompanied these 

 expeditions, and ever since then he has continued to collect in this 

 field. Some of his earlier material went to the Carnegie Museum, 

 and recently some has been acquired by the American Museum of 

 Natural History, but most of it is in the United States National 

 Museum. The largest collections were made by him from 1908 to 

 1911, under grants from the United States Geological Survey and the 

 National Museum. The result is one of the richest, most varied, and 

 most important Paleocene mammal collections ever made. 



The late Dr. James W. Gidley, assistant curator of fossil mammals 

 in the National Museum, visited the field in 1909. Concurrently 

 with his other duties and interests. Dr. Gidley set about the long 

 task of preparing the specimens in the National Museum, and essen- 

 tially completed it in 1920. He published four papers based on or 

 including part of this material, ^ and he planned to publish a memoir 



' Notes on the fossil mammalian genus Plilodus, with descriptions of new species. Proc. U. S. Nat. Mus. 

 vol. 36, pp. 611-626, 1909. 



An e.xtinct marsupial from the Fort Union with notes on the Myrmecobidae and other families of this 

 group. Proc. U. S. Nat. Mus., vol. 48, pp. 395-402, 1915. 



New species of claenodonts from the Fort Union (Basal Eocene) of Montana. Bull. Amer. Mus. Nat. 

 Hist., vol. 41, pp. 541-555, 1919. 



Paleocene primates of the Fort Union, with discussion of relationships of Eocene primates. Proc. U. S. 

 Nat. Mus., vol. 63, art. 1, pp. 1-38, 1923. 



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