244 



DOUGLASS — FOSSIL MAMMALIA 



Besides the above there are at least three localities where fragments of fossils that are 

 almost certainly White Eiver have been collected. They are north of Avon in Deer 

 Lodge county, at Glendale in Beaverhead county, and west of Puller Springs near the 

 Ruby river in Madison county. 



In Montana vertebrate fossils of the Tertiary have not been found in anything like 

 abundance except at two or three restricted localities, and these long distances apart, 

 though a few have been found in as many as twenty different places. In the White 

 River they were the most numerous on Pipestone creek, but they are mostly isolated 

 teeth, jaws and other bones of small animals. Certain strata are quite rich in fossils, 

 but on account of their dip and their being, as a rule, covered with vegetation or debris, 

 they are exposed for only short distances. It is curious, though, that in all the; beds m 

 which collecting has been done surprisingly few duplicates have been obtained, and few 

 of the things have been found anywhere else. The White River collection, as it has been 

 studied and compared with those of other regions, has caused continual surprise on account 

 of its great difference from them. The explanation seems to lie partly in the fact that in 

 Montana we have quite a rich fauna from a horizon nearly or quite corresponding to 

 the lower White River or Titanotherium beds of South Dakota, where few fossils except 

 Titanotheres have been found. Though the fossils were scattered over a large area 

 (about 150 by 170 miles) and were not especially abundant, yet during the six years 

 that I spent in Montana a good-sized collection was secured. 



Most of my time while in the field has been employed in the search for fossils, and I 

 have never seen the corresponding Tertiary formations in other regions, yet I have made 

 some observations that may be interesting. W. I). Matthews' paper, "Is the White 

 River Tertiary an iEolian Deposit ?" (Amer. Nat., May, 1899), has added new interest 

 to the study of these so-cdled lake bed deposits. There certainly is much mystery con- 

 cerning their origin and the way in which the animal remains became fossilized. The 

 fossils from Montana are different in appearance and are enclosed in a different matrix 

 from those that are found in South Dakota. As has been said of the former (referring 

 to color, etc.), "They do not look like White River fossils." 



Most of the material in the bids that are undoubtedly White River is light colored, 

 line grained, and soft, though thjre are some layers of coarser and harder material. 

 The same is true of the beds that, from their Lithological characters and imperfect fossils, 

 have been supposed to belong to the same horizon. The nearness or distance! of the shore 

 or the mountains and the character of the contiguous rocks seem to have little influence 

 on the character or composition of the sediments. 



1 have made microscopic examination of samples from the several fossil-bearing beds, 

 and all contain minute' fragments (indistinguishable from the glass fragments from the 



