378 INDEX TO THE STRATIGEAPHY OF NORTH AMERICA. 



the Uinta Range about 600 feet of the 1,070 feet of beds that have been correlated with the 

 Wasatch hmestone are certainly of Mississippian age. Powell correlated the beds of the Wasatch 

 limestone with his Grand Canyon section. They correspond in general to the Redwall group 



The basal beds of this series are buff, blue, and gray limestones weathering darker in color, 

 and some of them have a decided greenish tinge. They are usually in massive, brecciated beds 

 having a thickness of 150 to 200 feet. Besides the brecciation or fracturing, many small faults 

 occur in them. The succeeding beds, 6 inches to 1 foot thick, are buff-colored crystalline lime- 

 stones having a total thickness of 300 feet, followed by 25 feet of thinner-bedded dark-blue and 

 purple limestones containing a large amount of dark-colored chert. The fossils found in the 



above-described beds indicate that they are of Mississippian age. 



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The Pennsylvanian series comprises the upper part of the Wasatch limestone and the 

 Weber formation. No name is given to the limestones of this series occurring beneath the 

 Weber formation, leaving it for future detailed work to determine the beds which are to be 

 assigned to this formation. In the Wasatch Mountains a similar succession of strata is exposed. 

 In Powell's Grand Canyon section, Lower Aubrey group, and the Yampa sandstone of the Upper 

 Aubrey group correspond to the Pennsylvanian series. The limestones below the Weber forma- 

 tion are to be correlated with the Lower Aubrey limestone and the Weber formation with the 

 Aubrey sandstone of Walcott's section. So far as the faunas are known, they corroborate 

 these correlations. 



The strata forming this subdivision are 300 to 500 feet of light-blue and gray limestones 

 containing a considerable amount of light-colored chert, interstratified with fine-grained hght- 

 gray sandstones wliich toward the top contain bands of sandstone weathering brown and resem- 

 bhng in a marked degree the weathered material of the "Uitita " sandstone. These are succeeded 

 by the quartzites of the Weber formation. 



The lower part of the Weber formation is a white and gray to greenish quartzite in t hin 

 and thick beds, some of which weather brown. In the upper part of the formation are alter- 

 nating blue and white siliceous limestones and quartzites. The transition to the next series 

 is through blue and reddish limestones and shales. The greatest thickness occurs on the south 

 side of the Weber River, on the north slope of the range. To the east, on this side of the range, 

 the formation is largely covered by Tertiary sediments or glacial debris. On the opposite (south) 

 side of the range the formation is well exposed in all the principal canyons from the Provo River 

 to Green River. This formation, like the "Uinta," is quartzitic in the western and central parts 

 of the range and grades into a rather soft sandstone in the eastern part. No fossils were found 

 in the Weber formation. 



The Permo-Carboniferous series of the Uinta Range seems to correspond in position, thick- 

 ness, and general lithologic characters to the Upper Coal Measure and Permo-Carboniferous 

 formations of the Fortieth Parallel Survey. On similar grounds they may be correlated with 

 the Aubrey limestone [Pennsylvanian] of Walcott's Grand Canyon section. The correlation 

 with Powell's section is less definite. The limestones overlying the Yampa sandstone of the 

 Upper Aubrey group and an undetermined thickness of the shales and soft sandstones of the 

 Shinarump group appear to correspond to the beds under discussion. 



The upper beds of the Weber formation are calcareous sandstones and siUceous Umestones 

 which weather yellow and grade into thin red shales and red and blue Hmestones of the upper 

 part of the Permo-Carboniferous series. This series is well exposed on the Duchesne River, 

 Rock Creek, Whiterocks Creek, on the south side of the range, and in the Horseshoe Canyon of 

 Green River, on the north side of the range. 



One of the best sections occurs on the east side of the Duchesne River below the mouth of 

 West Fork. There the lower 600 feet of the Permo-Carboniferous are formed of red and purple 

 shales and blue limestones. Above is 1,000 feet of light-gray and white sandstones, with some 

 interbedded limestones in the lower part. In the upper part these sandstones occur in alter- 

 nating layers of soft and compact beds full of pecuUar black points or specks. These are 

 succeeded by 800 to 900 feet of red shales, with a prominent band of light-colored shale at the top. 



