17 



which are very okl in appearance and remarkably distorted, twisted, and 

 broken. 



The principal growth of the plains consists of sage-l>ushes {Arteiiiesia tri- 

 dentatii) curiously distorted and split, so as to I'eniind one of the cedars just 

 mentioned. In some places the sage-bushes are mingled witii or replaced I>y 

 the gi-ease-wood, {Sarcobatus vermiculatus.) Wide, bare, path-like intervals 

 surround the bushes, or the spaces are occupied by scanty grass, which 

 formerly furnished food to the buffalo, now become extinct in this region 

 and elsewhere west of the Rocky Mountains.* 



The fossils which form the subjects of our communication for the most 

 part were derived from tire more superficial deposits of the great Uintah basin, 

 which Professor Hayden has distinguished as the Bridger group of beds. 

 These compose the terraces or table-lands in the neighborhood of Fort 

 Bridger, and consist of nearly horizontal strata of variously colored indurated 

 clays and sandstones. As the beds wear away, through atmospheric agencies, 

 on the naked declivities of the flat-topped hills, the fossils become exposed to 

 view and tumble down to the base of. the hills among the crumbling debris 

 of the beds. 



The flat-topped hills or terraces of the Bridger basin, rising from Ijroad 

 valleys and extended plains, form the most conspicuous objects of the land- 

 scape. A similar condition of the country, alternating with boundless plains 

 and great mountain heights, forms a charactei'istic feature of a great part ol 

 the region west of the Mississippi. 



The flat-topped hills, table-lands, bench-lands, or terraces, as they are 

 variously named, seen from lower levels, are usually called "buttes," especially 

 when they are of limited extent. The name is of French origin, and signifies 

 a bank of earth or rising ground. The name is likewise applied in a more 

 restricted sense to the prominent irregularities of the deeply eroded and 

 naked declivities of the more extended terraces. The buttes therefore vary 

 in extent from a mere mound rising slightly above the level of the plains to 



* It has already become a question whether the buffalo existed west of the Eocky 

 Mountains at a couiparativelj' recent period. That it did so was amply proved to the 

 writer from his having noticed rem.ains of the animal in a number of places, from ravines 

 skirting the Union Paciiic liailroad to the forests high up in the foothills of the Uintali 

 Mountains. Judge W. A. Garter, of Fort Bridger, informs us that some of the old trap- 

 pers iuid hunters of the district had told him that in their early days they had seen the 

 buffalo in abundance in that country. 



