CORRELATION 301 



The Uinta quartzites occupy a position corresponding to the Pre- 

 Cambrian series in the Grand canj'on which Powell included under the 

 general name of Grand Canyon series. This has since been subdivided 

 into the Chuar, Grand Canyon, and Vishnu series, each separated by an 

 unconformity, only the lower member of which, the Vishnu, resembles 

 lithologically the Uinta quartzite. 



Powell failed to recognize the Permo-Carboniferous in the Uintas, as 

 he did in the Grand canyon, but in other respects his geological column 

 in the Uintas above the Carboniferous corresponds fairly well with that 

 of the Fortieth Parallel, though the formations are given different names 

 and their lines of diversion are placed at somewhat differing horizons. 



The greatest uncertainty that still remains is in regard to the proper 

 correlation of the Ogden quartzite and the Shale series. If we correlate 

 with the Wasatch section, they correspond best with the Cambrian of the 

 Big Cottonwood section; if with the Grand Canyon section, they fit best 

 the Tonto, which consists of shales and sandstones. 



There is still some uncertainty as to the location of Powell's uncon- 

 formity in the western Uintas, if indeed it exists there. Owing to the 

 want of precision in his published statements, it is difficult to verify his 

 observations in the field. As already stated, I think its most probable 

 place is between the Ogden quartzite and the Shale series. 



The Uinta quartzites I regard as undoubtedly of Pre-Cambrian age, 

 but, like most Pre-Cambrian formations in the West, which are widely 

 separated and generally barren of fossils, its exact correlation will for a 

 long time probably remain in doubt. 



Origin of Green River 



The statement of Powell, in his volume "Exploration of the Colorado 

 River of the West," with regard to Green river, to which he assigns an 

 antecedent origin, thereby furnishing a striking proof of the slowness of 

 the movement of mountain uplift, picturesquely comparing the contem- 

 poraneous uplift of the Uinta mountains and the corrasion of the Green 

 River canyons Math movement of a saw-log relative to a buzz-saw, have 

 been accepted and quoted by many writers of text-books on geology. My 

 theory that it is a superposed river, based on the occurrence of remnants 

 of Wyoming congiomerate (Bishop Mountain conglomerate of Powell) 

 resting unconformably on all underlying formations, and so situated that 

 when connected together they must have entirely covered that part of 

 the range through which the Green River canyons are now cut, has re- 

 ceived less notice ; nevertheless it has been accepted by such authorities as 



