MOVEMENTS RECOGNIZED BY CLARENCE KING. 241 



Of these he considers that the work of the first movement was to throw 

 the original crust of crystalline sediments into waves within the present prov- 

 inces of the Wasatch and of the Rocky Mountains. His post- Archaean move- 

 ments, which produced the land areas in the Cambrian seas and would now 

 be designated post-Algonkian, extended over the whole breadth of the Cor- 

 dilleras. 



The post-Palreozoic or post-Carboniferous movement produced a continental 

 elevation from the Wasatch westward to longitude 107° 30'. Its effects w r ere 

 most marked at the western edge of this area; and east of it, with the excep- 

 tion of slight unconformity by erosion in the Wasatch,* no direct proof of 

 movement was observed, though there is evidence of shallow water deposi- 

 tion in the succeeding Permian and Mesozoic sediments. 



The post-Jurassic movement was likewise considered by him to be mainly 

 confined to the western part of the Cordilleran system, the evidence of un- 

 conformable deposition found at that time being too slight to justify the 

 assumption of the general extension of the movement to the east of the 

 Wasatch. It is to this movement that he ascribes the original formation of 

 the peculiar parallel ranges of the geological province of the Great Basin — 

 the Basin Ranges, as they are called — a movement due to tangential com- 

 pression resulting in contraction and plication f which he distinguishes from 

 the later movements in the same region, presumably Tertiary or later, in 

 which there are few evidences or traces of tangential compression. The 

 principal effect of this later movement has been the faulting and uplifting of 

 irregular areas with little or no attendant plicatiou. Where the effects of 

 the earlier movements were not felt, or have been obscured by erosion and by 

 later sediments and extensive flows of eruptive rock, only those due to the 

 later movement are readily manifested. Hence a number of geologists, 

 whose observations have been principally in such parts of the region, have 

 considered it characteristic of the whole and given the name " Basin Range 

 structure " to this later phase of its orography. 



The post-Cretaeeous movement was principally manifested east of the 

 Wasatch, the Uinta uplift dating from this period, and the principal eleva- 

 tion of the Rocky Mountain region and the final shutting-out of ocean 

 waters from the whole Cordilleran system east of the Sierra Nevada being 

 due to it. 



The subsecpient movements during Tertiary and Recent times were foldings, 

 upheavals, and subsidences within a continental area, to be measured not by 

 their relations to sea level, but to that of adjoining land elevations or inte- 

 rior lakes. Thus, those numbered 6, 7, and 8 are shown in successive eleva- 

 tions of the Uinta mountains and in modifications in the adjoining Tertiary 

 lakes whose sediments were largely derived from the abrasion of the broad 

 crest of that range. 



I >p. cit., p. 228. t Op. eit.,p. 744. 



