328 ELIOT BLACKW ELDER 



of the Gros Ventre Range, two well-defined lateral moraines, with- 

 out any terminal junction, have been beheaded upstream by the 

 excavation of the inner valley of the modern Shoal Creek. On 

 account of the much more rapid destruction of lateral moraines 

 where they rest on steep slopes in soft rocks, the old lateral moraine 

 at Sunday Peak on the Gros Ventre River has been almost com- 

 pletely destroyed by the development of numerous short ravines 

 in the Cretaceous shale. 



Some of the best examples of the Bull Lake moraines are to be 

 found near the mouth of Crystal Creek (Fig. 43), and near the 

 mouth of Fish Creek (Fig. 44) in the Mount Leidy quadrangle, 

 along Green River south of Kendall in the Gros Ventre quadrangle, 

 and the older moraines of Bull Lake, DuNoir River, and Dinwoody 

 Creek in the Wind River basin. At the mouth of Teton canyon, 

 on the west slope of the Teton Range, distinct lateral moraines 

 have been cut into short lengths and yet they are still connected 

 downstream by the eroded remains of a bulbous terminal moraine. 

 On the basis of similarity of conditions these deposits are corre- 

 lated with the moraines of the Bull Lake glacial stage. 



The glaciers of the Bull Lake epoch were in most instances 

 longer than those of the Pinedale epoch. Thus, on Crystal Creek 

 the difference in length was about four miles, on the Gros Ventre 

 River about nine miles, and on Green River apparently twenty-five 

 miles. On the north slope of the Wind River Range, however, 

 there seems to have been but little difference in length, and the 

 Pinedale moraines in the valleys of Bull Lake and Dinwoody Creeks 

 were even advanced a fraction of a mile farther than the older 

 terminal moraines. 



Buffalo stage: Certain other glacial deposits, which are evi- 

 dently very much older, are readily differentiated. These may 

 be called the Buffalo drift, from their typical occurrence along 

 Buffalo Fork of Snake River. The deposits which appear to repre- 

 sent this stage now exist only in the form of remnants on flat-topped 

 divides or isolated hills, or on spurs along valley slopes. Such sur- 

 faces have already (p. 312) been correlated as belonging to the Black 

 Rock cycle of stream erosion. The grouping of these remnants 

 suggests that they are parts of originally more extensive bodies 



