438 F. B. WEEKS STRATIGRAPHY OF THE UNITA RANGE 



Description. — Tlie 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. Beside the brecciation or fracturing, many 

 small faults occur in them. The succeeding beds, 6 inches to one foot 

 thick, are buff-colored crystalline limestones having a total thickness of 

 300 feet, foUovi^ed by 25 feet of thinner bedded, dark blue, and purple 

 limestones containing a large amou^nt of dark-colored chert. The fossils 

 found in the above described beds indicate that they are of Mississippian 

 age. 



The lower beds form bold, massive outcrops in nearly every canyon on 

 both slopes of the range. Where broken by faulting of fractured, they 

 contain gold and silver associated with iron deposits ; but little is known 

 of their value. Prospecting in these beds was in progress in several can- 

 yons in the summer of 1906. 



Pennsylvanian series — Nomenclature and correlation. — This series 

 comprises the upper part of the Wasatch limestone and the Weber forma- 

 tion. No name is given to the limestones of this series occiirring benealh 

 the Weber formation, leaving it for future detailed work to determine the 

 beds which are to be assigned to this formation. In the Wasatch moun- 

 tains a similar succession of strata is exposed. In Powell's Grand Can- 

 yon section. Lower Aubrey group and the Yampa sandstone of the Upper 

 Aubrey group correspond to the Pennsylvanian series. The limestones 

 below the Weber formation are to be correlated with the Lower Aubrey 

 limestone, and the Weber formation with the Aubrey sandstone of Wal- 

 cott's section. So far as the faunas are known, they corroborate these 

 correlations. 



Description. — 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 light gray sandstones 

 which toward the top contain bands of sandstone weathering brown and 

 resembling in marked degree the weathered material of the "Uinta" sand- 

 stone. These are succeeded by the quartzites of the Weber formation. 



Weber formation. — The lower part of this fonnation is a white and 

 gray to greenish quartzite in thin and thick beds, some of which weather 

 brown. In the upper part of the formation are alternating 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 



