LOXOLOPHODON AND 



UINTA THERI UM. 



13 



which the waters occupied as they slowly retired ? King leaves the matter in 

 doubt, expressing however, the opinion that it is improbable that erosion 

 could have totally removed all traces of the Bridger rocks from the country 

 lying between the Washakie and Bridger basins. He therefore rather favors 

 the view that the waters in which the Bridger beds were formed were not con- 

 tinuous. This view, it appears to the writer, may be sustained on two 

 grounds. First, the nature of the rocks in the Washakie and Bridger basins is 

 somewhat different ; secondly, the character of the fauna is more dissimilar than 

 we should expect to find it at opposite ends of a continuous shore. The prevail- 

 ing colors among the Bridger Basin strata are light grays and drabs, with an 

 occasional green. In the Washakie beds the colors are much more brilliant; 

 many of the strata are a very brilliant green, others have a brownish-red hue. 

 The manner of weathering is dissimilar ; in the Washakie basin the occasional 

 beds of harder rock form bold cappings for the softer strata beneath, result- 

 ing in mushroom-like forms, which are rarely seen in the Bridger basin. 

 More important is the evidence derived from the character of the fauna, found 

 in the deposits of the two basins. During the summer of 1877 the Princeton 

 party collected wholly in the Bridger-basin area. The dominant species 

 were Palceosyops and Hyrachyus. The remains of Uintatherium (Dinoceras) 

 were quite abundant ; and two species of the Camivora, a small rodent, and 

 numerous quadrumanous forms were obtained. A doubtful Artiodactyle form 

 was secured, referred to the camel tribe. A second tour through these beds, 

 in the following summer, resulted in the collection of other individuals belonging 

 to the same orders. In the summer of 1878, the party spent six weeks in 

 the Washakie Basin beds. Here the number of Loxolophodon remains was sur- 

 prising, especially in the upper strata. Not a single specimen of the allied 

 genus, Uintatherium, was obtained. Prof. Cope has, however, reported a single 

 species of Uintatherium from these beds, on a rather doubtful determination. 

 He found here several species of Loxolophodon. It certainly appears that the 

 latter genus ranged exclusively in this region, while it is possible that some 

 species of Uintatherium found their way here, but not in great numbers. In 

 the lower Washakie-basin strata, in a matrix quite different from anything 

 found in the Bridger, we discovered the skeleton of an Achcenodon, one of 

 the Bunodont Artiodactyla, and an unspecialized member of the Rhinoceros 

 family. Palceosyops was rarely found. Hyrachyus has been obtained by Cope 

 in these beds. It is unfortunate that the localities in which the Bridsfer- 

 group fossils have been discovered have not been more frequently published, 

 as data of this description would greatly aid in determining the extent of the 

 third Eocene lake, as well as giving a clue to the migrations of these forms. 

 Our own discoveries point to the distribution of several genera over the region 



