EESUME OF LITEEATUEE. 33 



the Grand Canyon group, 10,000 feet of sandstones and conglomerates, and this in 

 turn rests unconformably upon the Grand Canyon schists. The Grand Canyon 

 schists and the Ked Creek quartzite Powell regards as of Eozoic age, and the Grand 

 Can^-on group he refers to the Silurian (pages 56, 10). Upon this construction of 

 the facts the Grand Canj^on schists and the Red Creek quartzite would be in a 

 manner correlated, and the Grand Canyon group of the Grand Canyon area would 

 underlie the Uinta group of the Uinta area, neither great series heing represented 

 in lioth regions. It would appear from this that in Paleozoic time at least the two 

 regions jjassed through very different geologic histories. -In fact, however, it appears 

 to me more probable that the Grand Canyon group is to lie correlated with the Red 

 Creek quartzite and that both are Algonkian. 



A critical study of the paleontologic evidence reveals discrepancies well nigh 

 as marked as those shown by the comparison of the geologic sequence. 



But a single Carboniferous species is cited bj^ White as having been obtained in 

 Colorado itself, but more or less extensive collections were made in portions of the 

 Uinta ^Mountains which lie beyond its confines in the State of Utah. No fossils are 

 cited from the Red Wall limestone in the Uinta Mountains, but three collections were 

 made in the lower Aubrey formation and one in the upper Aubrej\ The only 

 faunas known from the Red Wall group were collected at two stations situated close 

 together southeast of the central part of Utah. From Gvpsum Canyon were obtained 

 C'ha^fete-s inilleporaeem and SyruK/ojjora muHattenuata., and from Cataract Canyon 

 an undetermined species of Campophyllum . These faunas, so far as they go, are quite 

 dissimilar, but are yet so limited that they might readily have come from the same 

 bed, somewhat the more because the zoologic relations of the three species are all 

 with the same class, the corals. On looking up the collections upon which this 

 I'eport was based the specimens referred to Ch. miUeporaceus could not be found. 

 The original material of S. inultattenuata , as well as it could be identified, consists 

 of an external cast, and can not be definitely determined. The Oampophylhim is 

 probably that form from the Diamond Mountains figured by Meek in the reports of 

 the King sui'vey." The evidence therefore, whether of the lists or of the fossils, is 

 inconclusive, but so far as it goes is coincident in indicating Upper Carboniferous. 



In the detailed section at Cataract Canj^on, given b}^ Powell on p. 60, the Red 

 "\^'^all group is described as huffish lavender, friable, fine-grained sandstone; base not 

 seen. This is not at all the character of the real Red Wall limestone, and these beds 

 more probably belong above the Red Wall, in the lower Aubre}' series. Thus the 

 stratigraphic and paleontologic evidence agree in discrediting Powell's identification 

 of the Red Wall at this place. At the same time it should not be lost sight of that 

 the upper half of the tj^pical Red Wall belongs in the Pennsylvanian. 



aV. S. Geol. Expl. 40th Par., Kept., vol. 4, 1S77, p. 57, pi. 5, flgs. 2,26. 



14364— No. 16—03 3 



