THE FORTIETH PARALLEL SURVEY. 50'3 



The next series of supposed Archsean rocks is in the Uinta Range. 

 The rocks there, according to Mr. King, are quartzites and homblendic 

 and hydro-mica schists. Another quartzite unconformably overlying 

 it, and said to contain fragments of the Archaean (I., p. 154), is referred 

 with doubt to the Carboniferous. In some places the Archaean gives 

 evidence of having been uplifted since the Fox Hill Cretaceous (II., 

 p. 268). Mr. Emmons, it seems, would refer these rocks to the Huro- 

 nian on accoimt of their lithological characters. 



The Wahsatch Range was regarded as the type of the Archaean (Azoic) 

 exposures in the district covered by Mr. King's survey. It is, how- 

 ever, more difficult to make out from the writings of Mr. King and 

 his coadjutors what they believe its history to have been, than it is to 

 learn their ideas of any of the other districts within their field of ex- 

 ploration. It would also seem that in some places their views regarding 

 the origin of the granites, and the geology of the Wahsatch Range, iu 

 general, had decidedly changed during the time which elapsed between 

 the publication of Volumes VI. and I. ; Volume II, representing the 

 later transition period, with a still greater change since Volume III. was 

 published. In order to give some idea of the views of Messrs. King, 

 Emmons, and Hague, it is necessary to quote to some extent from their 

 writings, as well as from Volume VI. 



At the time of the publication of Volume III. (1870), it seems Mr. 

 King held that the granites were all of eruptive oi'igin, and of Jurassic 

 age ; while the stratified rocks in his district were regarded as conform- 

 able from " the early Azoic up to the late Jurassic period." In that 

 volume Mr. King says (III., pp. 2, 3) of the region covered by his 

 Survey : — 



" The greater part of the rock is a series of conformable stratified be^ls, 

 reaching from the early Azoic up to the late Jurassic period, when these level 

 beds were compressed into vast mountain corrugations and elevated above the 

 sea in a general, wide, and high plateau. Accompanying the upheaval and 

 crumpling of this great oceanic family, and bursting from its fractured fokls, 

 are important masses of granite, penetrating the axes of the flexures and break- 

 ing through lateral fissures. Quartz-porphyries, felsite rocks, and notably 

 syenitic granite, with occasional occurrences of granulite and greisen, ac- 

 company the ejections of granite. The date of their orographical period is 

 assigned to the late Jurassic on grounds which will be found fully discussed 

 in the first volume of the present series This Exploration has demon- 

 strated that all the parallel ranges of the Great Biisin, includhig the chain 

 of the Wahsatch, its eastern wall, belong to the same system [Jurassic] of 

 upheaval." 



