428 F. B. WEEKS STRATIGRAPHY OF THE UNITA RANGE 



Page 



Post-Paleozoic 439 



Trias 439 



Jura 440 



Cretaceous 440 



Tertiary 440 



Interpretation of the sedimentary record 441 



Unconformities in the Uinta region 441 



Structure 442 



In general 442 



General structural features of southern slope 443 



General structural features of northern slope 443 



Extent of major fold 444 



Other similar folds 445 



Age of the folding 445 



Degradation 446 



Geologic history 446 



References 448 



Introduction 



The geologic history of the Uinta region has been described by King 

 and Emmons in the reports of the U. S. Geological Exploration of the 

 Fortieth Parallel^ and of the eastern portion by Powell in his Geology of 

 the Uinta mountains. Por more than 30 years these reports have com- 

 prised the extent of our knowledge of this interesting section. Kecently 

 Berkey published in the Proceedings of this Society an' account of a 

 reconnaissance in the Duchesne region and discussed the bearing of his 

 observations on the stratigraphy and structure. The 40th Parallel 

 geologists had studied the ranges of northern Nevada and Utah, while 

 Powell's previous work had been in the Grand canyon of the Colorado and 

 the plateau region of eastern Utah. The nomenclature and correlations 

 of the two explorations varied considerably. 



Having taken part in several reconnaissance trips in Nevada and north- 

 ern, central, and western Utah in previous years, I was able during the 

 summer of 1906 to extend this work over the Uinta range. About six 

 weeks were devoted to this reconnaissance, which extended from the 

 Wasatch mountains along the southern flank of the Uinta to the vicinity 

 of Vernal, Utah; thence, crossing the range to the north, a side trip was 

 made to Eed creek, about 25 miles east of Green river; thence, returning 

 westward, it followed the north slope and around the western end to the 



