198 CAKHONIKKKOI'S FORMATIONS AND KAUNAS OK COI.OHADO. 



st'clioii inaclc al Fliuniiiy Gorg'e, in llic I'iiitu Mimntaiiis, (lie scries coiupriscs 1,(11(5 

 t'eot of sliiilcs aiul sandstones containini;' much gypsum and wcathcriiii;' in many 

 colors, but with provalont tints of Ijrown and chocohitp. I( is succeeded by the lied 

 Beds series, consisting of the Vermilion Ciitf, Wiiite Cliil', and Flaming Gorge 

 groups, \\ liicii, together witii tiie Sliinarump. Powell places in tlic Juratrias. 



The Uinta series of Powell is usuallj' called by King the Weber quartzite. 'rh(> 

 Lodoro, Red Wall, Lower Aubrey, and Upper Aubrey groups are collectively cited 

 by King as the Upper Coal Measures. The upper limit of King's Upper Coal 

 Measure series is oviden.tl}' precisely that of Powell's Upper Aubrey group, both 

 being determined by the Bellerophon limestone; but it can not be said with equal 

 certainty that both drew the line between the Uinta sandstone and the overlying- 

 beds at exactly the same point. From 200 to 500 feet of Powell's Shinarump group 

 are subtracted by King under the name of the Permo-Carboniferous series. The 

 rest of the Shinarump, together with the White Cliff and Vermilion Cliff groups of 

 Powell, ai'e King's Triassic; the Flaming Gorge gi'oup his Jurassic, etc. 



Several disagreements are found between Powell's and King's accounts of the 

 geology of this area, the chief of which are as follows: Powell describes a great 

 unconformity between the Uinta sandstone and the Lodore group, which was not 

 observed by the geologists of the Fortieth Parallel Survey. The combined thickness 

 of the four groups, which taken together form the Upper Coal Measure series of 

 King, is over 5,000 feet," while King assigns to that series a thickness of but from 

 2,000 to 2,500 feet. Finalh" , Powell refei's the Uinta sandstone to the Devonian, 

 while by King's correlation it would be Pennsylvanian. Powell's correlation implied 

 in the use of the name Red Wall, would make the Uinta sandstone probably pre- 

 Carboniferous in age, since the base of the true Red Wall is Lower Mississippian.'' 

 I am forced to conclude, therefore, that Powell's correlation is erroneous, that of 

 Emmons and King being probabty correct, and that the upper part of the Uinta 

 sandstone at least is of Pennsylvanian age, the overlying beds being, of course, still 

 younger. This conclusion seems to be demanded by the following facts: 



1. Because Emmons traced the Uinta sandstone westward into the Wasatch 

 Range, finding its equivalent to be the Weber quartzite, the age of which, as deter- 

 mined b}' fossils, is Penns3'lvanian. 



2. Because the supposed Red Wall limestone at Gypsum and Cataract canyons 

 furnished a few fossils probabl^^ indicating Upper Carboniferous. 



3. Because a Pennsylvanian fauna was found at the very base of the Upper Coal 

 Measures of King. 



n As determined by PoweU's detailed section, which would naturally be supposed to be more exact than the statement 

 in round numbers made elsewhere. 



bin the Grand Canyon region both Meek, Walcott, and Freeh agree in a general way in referring the lower portion of 

 the Red Wall to the Mississippian series, and our collection also contains Mississippian fossils from it. 



