894 GEOLOGICAL EXCURSION TO THE ROCKY MOUNTAINS. 



the upper portion of the canyon. Their boulders have furnished the 

 material for the Temple at Salt Lake City. 



Just south of Little Cottonwood canyon a shallower valley called 

 Dry Cottonwood descends the mountain face, and this, too, carried a 

 Pleistocene glacier descending to the mountain base. The lateral mo- 

 raines in this case; coalesce with a massive terminal which the modern 

 creek has notched but not yet divided. 



Across the two pairs of lateral moraines and across the Hood plains 

 of thecreeks rnns a line of faulting characterized by the settling of great 

 belts of earth. A portion of the north moraine of Little Cottonwood 

 creek has dropped between parallel fault planes as much as 60 feet 

 (15 m.), and this so recently that the escarpments are not yet covered 

 by vegetation (PI. VII). The longitudinal profiles of the other mo- 

 raines, originally simple curves, have been made serrate, and the inner 



FlQ. 20. -Profile Of South Moraine at mouth of Little Cottonwood canyon. 



laces of the moraines, originally smooth, have been furrowed and 

 ridged in sympathy with the serrations. One of the fault caused ter 

 races of the northern Hood plain has been utilized in the construction 

 of an ore-smelting establishment. It is an impressive fact that the 

 stream, a roaring torrent every spring, has not yet been able to recon- 

 struct its dislocated Hood plain. 



We arc here brought face to face with a process of mountain-making 

 in actual progress. The Wasatch has grown perceptibly within a few 

 years, and the gathering orogenic strains may culminate any day in 

 another convulsive leap. It is a dictum of dynamic geology that great 

 mountains arc young mountains; r ' :> and the greatest of the mountains 

 of the, Salt Lake basin has not yet ceased to grow. 



