UINTA UrLIFT. 199 



qiiartzites, a middle series of purple, coarse qiiartzites, and an upper of red 

 and striped sandstones, in all of which no unconformitj was observed; 

 they are in general barren of all fossil remains, only two species of Spirifer 

 obtained from quartzite debris having been found by us ; but as they are quite 

 conformable with the limestones of the Upper Coal-Measure group, which 

 abound in well-defined fossil remains, they have been referred to the Weber 

 Quartzite group. 



Their thickness, as observed in different parts of the range, is from 

 10,000 to 12,000 feet, while, as their base is never reached, the actual 

 thickness of the formation may be indefinitely greater. This fact 

 might seem to throw some doubt upon the correctness of the assump- 

 tion that they all belong to the Carboniferous formation, since the Weber 

 Quartzite, in the Wahsatch Range, at a comparatively short distance to the 

 west, attains a development of only 5,000 to 7,000 feet, and the general 

 tendency of all the formations is to thin out to the eastward. Lithologi- 

 cally also the lower beds of this group resemble, perhaps, the Cambrian, 

 rather than the Weber Quartzite of the Wahsatch, and it might be sup- 

 posed that the upper portion of this group had been deposited over a 

 shallow, rounding uplift of Cambrian rocks in such a manner as to show 

 no appreciable unconformity of angle.^ 



The Upper Coal-Measure group is represented by a body of lime- 

 stones and fine-grained sandstones of prevailing light-gray and drab colors, 

 with some darker limestones at the base, in which the siliceous members 

 seem proportionately more developed at the eastern end of the range. Their 

 upper horizon is marked by a well-defined cherty limestone rich in fossils, 

 above which a series of clays and calcareous shales, whose character is not 

 well defined, though identified at one point by fossils, represents the Permo- 

 Carboniferous group. These beds are in general upturned at steep angles, 

 forming flanking parallel ridges, and only in the lower portions of the range, 

 east and west of the main elevation, are left in the comparatively horizontal 

 position which they occupied in the arch of the fold. 



' Since the above was written, there has been published, in the report of Prof. J. 

 W. Powell, on the Geology of the Eastern Uinta Mountains (p. 144), sections made 

 iu the cafions of the Green Eiver, showing an unconformity of deposition in these 

 beds, which, if correct, would seem to prove the latter supposition to be the more correct. 



