. 



530 E. BLACKWELDER GEOLOGY OF WASATCH MOUNTAINS, UTAH 



rest upon a cavernous weathered surface of fossiliferous gray limestone. 

 Just above the contact lies a coarse sandstone which consists of well 

 rounded frosted sand grains bound in a deep red matrix and including 

 bits of limestone and black chert from the underlying series. Although 

 the bedding of the Morgan formation is essentially parallel to that of the 

 limestone below, the relations here clearly indicate an unconformity, 

 signifying an erosion epoch between the Mississippian and the Pennsyl- 

 vanian.^^ 



In two small lots of fossils from the beds of limestone immediately 

 below the unconformity. Dr. G. H. Girty has identified the following 

 species : 



Campophyllum ? sp. Spirifer hoonensis f 



(IJoHsina nehraslcensis Spirifer cameratus ? 



Producta cora Spirifer kentuclcyensis ? 



Productus semireticulatus var. hermosanus Composita suMilita 



I'roductus nehraakersis Hustediamormoni 



Two other lots, one of them from a thin limestone within the Morgan 

 formation, and the other from transition beds at the top, yielded the 

 following : 



Monilipora prosseri Productus cora 



Zaphrentis gihsoni ? Productus gallatinensis 



Glossina nehraskensis f Spirifer rockymontanus 



LinguUdiscina utahensis Composita siihtilita 



Productus nebraskensis CUothyridina orMcularis 



It is obvious that these faunules are very closely related to each other, 

 and Girty assigns them all to the early part of the Pennsylvania period. 

 It appears, therefore, that although the contact features show an un- 

 conformity at the base of the Morgan formation, the erosion interval 

 must have been geologically brief. 



The red beds have been traced from Weber Canyon northward 5 or 6 

 miles to the point where they disappear beneath the Eocene strata. As it 

 has not been recognized in other parts of the region, the formation is 

 probably local in extent. 



THE DISAPPEARANCE OF THE WEBER QUARTZITE 



In the canyon of the Weber Eiver, just above the town of Morgan, the 

 geologists of the Survey of the 40th Parallel found a great quartzite for- 



2» It may be mentioned here that Berkey finds evidence of a well marked unconformity 

 above the Mississippian limestone on the southern flank of the Uinta Mountains (Bulle- 

 tin of the Geological Society of America, vol. 16, pp. 517-530. Stratigraphy of the 

 Uinta Mountains, 1905). His findings are questioned by Emmons (Bulletin of the Geo- 

 logical Society of America, vol. 18, 1907, pp. 287-302) and Boutwell (op. cit). 



