138 GEOGRAPHIC DISTRIBUTION. 



The group embraced under the name is the lowest horizon found within 

 the region under discussion. It is composed in large part of a quartzite, 

 very crystalline and white, and having the general aspect of virgin quartz. 

 Only in a few places is the original granular structure apparent. Intimately 

 associated with the quartzite are very irregular aggregations of hornblendic 

 and micaceous schists, the latter sometimes bearing garnets. Originally 

 these schists were perhaps argillaceous strata between the thicker strata 

 of pure siliceous sandstone. The whole group has been greatly metamor- 

 phosed, producing a crystallization that in many places has quite, and in the 

 remainder almost, obliterated the original granular or sedimentary structure, 

 so far as it is apparent to the naked eye. Besides this recrystallization they 

 have been profoundly plicated, or I should rather say implicated. It is 

 only in a general way that any original stratification can be observed. 

 This original structure can best be seen when standing at some distance 

 from the beds to be studied. 



Its relation to the Uinta Sandstone above it is exhibited in the lower 

 end of the canon of Red Creek and along the escarpment which faces 

 Brown's Park on the south side of Mount Wheeler, up the canon of an 

 intermittent stream four miles farther west, and also up the canon of Wil- 

 low Creek. Other facts relating to the junction of the two groups are seen 

 on the summit of Quartz Mountain. These facts are as follows: A part of 

 the Uinta Group, which is later and higher, terminates abruptly against the 

 quartzite. The thickness of the beds thus limited is about 8,000 feet, and 

 as the beds are traced from the southward to this plane of junction they 

 rapidly change from finer to coarser sediments, often appealing as conglom- 

 erates in the vicinity of the quartzite; but the total thickness of the beds 

 is not increased by the transition from finer to coarser sediments, though 

 particular beds may thicken, such thickening being compensated by the 

 thinning out or disappearance of others. In these conglomerates the coarser 

 materials are of quartzite, hornblendic rock, &c., similar to those of the' Red 

 Creek Group, held in a matrix of siliceous, hornblendic and micaceous 

 sands, w r hich are quite ferruginous. The position of the quartzite is on the 

 flank of the great Uinta flexure, not its axis, and the junction of the lower 

 two or three thousand feet of the Uinta Sandstone with the quartzite is not 



