294 



S. p. EMMONS UINTA MOUNTAINS 





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basis of these new facts constructed a geological 

 column which should reconcile the discrepancies 

 between the relative views assumed by him to have 

 been maintained by Powell and myself respec- 

 tively.* 



During the past summer, through the courtesy 

 of Mr F. B. Weeks, who was making the entire cir- 

 cuit of the range in a study of its Paleozoic ex- 

 posures, I was enabled to examine the Duchesne 

 valley and the region to the east of it, not visited 

 in my original work, which, as it happens, contains 

 the most continuous section in the entire range, 

 outside the Green Eiver canyons. The informa- 

 tion thus obtained, supplemented by general data 

 kindly furnished by Mr Weeks, has enabled me to 

 determine the general features of Uinta structure 

 with sufficient accuracy for immediate presenta- 

 tion, though there are many questions whose final 

 solution must still await a detailed areal survey 

 that may not be undertaken for many years. 



My observations bear testimony to the intelli- 

 gence and acumen of Mr Berkey's work, though I 

 am forced to differ with him on some important 

 l^oints, and hence my conclusions are somewhat at 

 variance with his. 



The Bear, Weber, and Duchesne rivers all have 

 their source on the same bit of plateau at the west 

 base of mount Agassiz, near the northern crest of 

 the range, the first two flowing northward, then 

 westward, to empty into ^alt lake, while the latter 

 courses south for 25 to 30 miles, and then bends 

 eastward to join the Green or Colorado river. The 

 first 12 miles of the Duchesne's course are in the 

 even and almost horizontally bedded Uinta quartz- 

 ites, through which it flows in a narrow, practically 

 impassable canyon, bounded by nearly vertical 

 cliffs. The canyon widens out quite suddenly in 

 the shales beyond the Iron Creek fault, but still 

 continues to form an imposing gorge 2,500 to 4,000 



This BuUetin, vol. 16, p. 517. 



