HEAD OF BEAR RIVER. 325 



head, of compact quartzite, many of them containing a good deal of specu- 

 lar iron, which seems to be conformable with the Carboniferous limestone. 

 This, however, is the only locality in which any such conglomerate was 

 found in the Upper Coal-Measure group, and it may possibly be a relic of 

 the Tertiaries or the Wyoming Conglomerate. 



In the ridge to the east of the right-hand fork of Bear River, as already 

 seen, is a good section of at least 8,000 feet of quartzite, upturned at an 

 angle of 45° to 52°, underlying the limestones of the Upper Coal-Measures; 

 and, on the low saddle between this fork and the head of Black's Fork, the 

 limestones of the Upper Coal-Measures are well exposed, the Tertiary con- 

 glomerates, which form the ridge below, having been eroded oflP. On this 

 ridge, also, is found the greatest thickness observed of undecomposed beds 

 of the Wyoming Conglomerate at Concrete Plateau, where 100 to 200 feet 

 still remain, consisting of pebbles of limestone and quartzite in a white 

 calcareous matrix. The continuation of the ridge to the northward forms 

 -the divide between the waters of Bear River and those which flow through 

 Muddy Creek into Green River. To what distance the Bridger beds ex- 

 tended in the upper portion of this ridge, it was impossible to determine, 

 since the hills were covered with soil and debris. 



