DISCOVERY OF THE TITANOTHERES AND ORIGINAL DESCRIPTIONS 



151 



AMERICAN MUSEUM AND OTHER EXPLORATIONS OF THE 

 EOCENE BASINS (1891-1895) 



The problems relating to Palaeosyops and its 

 allies, which had been barely made evident by the 

 pioneer discoveries and had now been partly formu- 

 lated by Earle, were of course only particular results 

 of the general explorations of the fossil-bearing forma- 

 tions of the West. The early explorations had been in 

 part reconnaissances, and their results were accordingly 

 incomplete as regards both the nature of the material 

 and the records of the stratigraphic levels at which the 

 specimens were found, both absolutely prerequisite to 

 a detailed knowledge of the phylogeny. 



exhibit a mounted composite skeleton of this animal. 

 Much other material was also collected by the same 

 party. All this material has been used profitably in 

 the present monograph, especially the specimens 

 representing the "prophet-horn stage," to which 

 Doctor Wortman in a letter from the field applied the 

 name Manteoceras. 



Another American Museum expedition, under Mr. 

 O. A. Peterson, went into the Uinta Basin in 1894 

 and examined two hitherto unexplored horizons (Uinta 

 B 2 and Uinta B 1 of this monograph), which underlie 

 the true Uinta (Uinta C). This expedition collected 

 many new forms and worked out the faunal sequence 

 of the three horizons indicated. Among the results 



Figure 86. — Osborn's first restoration of Palaeosyops paludosus Leidy 

 This restoration is a composite one— the skull from the fine specimens in the Academy of Natural Sciences of Philadelphia, and the axial 



skeleton from the material in the Princeton Museum, 

 twelfth natural size. 



The fore feet were afterward referred to Mesaiirhinus peterst 



The founding (in 1890) of the department of verte- 

 brate paleontology in the American Museum of 

 Natural History by Prof. Henry Fairfield Osborn and 

 the consequent establishment of continuous and syste- 

 matic exploration began a new era of exact investiga- 

 tion not only of the titanotheres but of the whole 

 series of vertebrate remains to be found in the Rocky 

 Mountains and Great Plains regions, as well as the 

 stratigraphic horizons at which they occur. 



The first of these expeditions, led by Dr. J. L. 

 Wortman, procured some important skeletal material 

 of "Palaeosyops" horealis from the Wind River forma- 

 tion. Another expedition, sent out under Doctor 

 Wortman in 1893, procured from the Bridger and 

 Washakie Basins extensive material of the true 

 Palaeosyops, enabling the American Museum to 



of this expedition, as reported in 1895, were the discus- 

 sion by Osborn and Peterson (Osborn, 1895.98) of the 

 three faunal levels (Uinta B 1, B 2, and C) and the 

 description by Osborn of the specialized and interest- 

 ing titanotheres named " TelmatotJierium" diploconum 

 and T. cornutum. Wortman's "prophet-horn" skulls 

 were referred to " Telmatotherium vallidens," so that 

 animals showing a wide range of form were here 

 erroneously included under a single genus. The 

 very aberrant form SpJienocoelus was also described, 

 but its ordinal and family positions were left "Incertae 

 sedis," on account of the lack of the teeth in the type 

 and the peculiar characters of the base of the skull. 



In the same year (1894) Mr. J. B. Hatcher, of the 

 Princeton Museum, also went into the true Uinta 

 area and discovered specimens representing the very 



