70 APPENDIX TO THE EEPORT OF THE SECRETARY. 



the east side at tbe sources of Torrey's Creek, presented most interesting 

 examples of many of the associated phenomena connected with the gla- 

 cier. But compared with their former extent these are but the merest 

 vestiges of the ice masses which flowed down and polished the canon- 

 walls of all the drainage courses which penetrate the range, and in the 

 amount of glaciation and the piled-up debris strewn along the sides of 

 the debouching valleys something like an adequate conception of their 

 former extent and comparatively recent dissipation may be formed. 



A few miles south of the canon of Green Eiver the older sedimenta- 

 ries have been entirely removed from the mountain border, the Tertiary 

 coming in contact with the bared Archaean rocks. Such are the 

 geologic features to the southern border of the district, and probably, 

 indeed, throughout the west flank to the extreme southern terminus at 

 South Pass. 



The eastern flank of this range was found to possess a much more ex- 

 tensive area occupied by the Palieozoic formations, which, for the most 

 part, are simply upraised, forming so many more or less well-marked in- 

 clined benches. The most recent of these is composed of the Carbon- 

 iferous, preceded by the magnesian limestone, Quebec limestone, and 

 primordial quartzites, which lithologically, and in the topographic fea- 

 tures molded out of them, bear close resemblance to the west flank of 

 the Teton Mountains. At no point were the Trias and later Mesozoic 

 formations found rising to any considerable elevation on the mountain 

 border ; on the contrary their presence marks the boundary between 

 the orographic and basin areas. The latter formations present in a gen- 

 eral way typical lithologic features characterizing their occurrence in 

 the region to the west, with however many and in some respects some- 

 Avhat strongly contrasted local stratigraphic peculiarities. The "red 

 beds" of the Trias exhibit enormous local accumulations of massive and 

 laminated gypsum, and the Cretaceous here contains seams of coal 

 which will become of economic value. 



In the Wind Eiver Basin the unconformable Tertiary occupies the 

 interval reaching over to the Owl Creek ^lountains to the northeast. 

 The border of this basin along the foot of the Wind Eiver Mountains 

 presents some extraordinary spring deposits of very modern date in 

 places incorporated with the gravel deposits occurring in terraces at 

 the foot of the mountains. Many, perhaps tlie majority, of the spring 

 sources have become extinct; but a few remain, evidently but feeble as 

 compared with their former volume, but which have built up quite ex- 

 tensive deposits of calcareous tufa. Some of the older deposits present 

 much the appearance of porous limestones forming extensive benches in 

 the mountain's foot. The presence of these deposits in some of the 

 cafions on this side of the mountains is associated with the most pictur- 

 esque scenery. All the streams that rise high up in the mountains 

 were formerly the beds "of extensive glaciers which built up the great 

 morainal ridges, like those which border the debouchiu^es of the Little 



