THE BUILDING OF THE COLORADO ROCKIES 



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divide the Grand River sweeps swiftly through the beautiful 

 Byers, Gore, and Grand River canyons on its way westward, 

 showing that, while the extent of the uplift varies from place to 

 place, the Rocky Mountain belt in this latitude was bowed up 

 throughout its full width. These are arnong the finest canyons 

 in Colorado and through their high, rugged walls they testify to the 



Fig. 3. — Rugged mountains sculptured from a smooth-sloped monadnock rising 

 above the peneplain on the continental divide. Long's Peak (14,255 feet) from 

 Taylor Peak (13,150 feet). Remnants of the smooth monadnock surface are seen 

 on the right-hand side of the photograph in McHenry's Peak and Chief's Head. 

 This surface was seemingly once continuous with the fiat summit of Long's Peak. 

 Glaciers stoping backward have cut profound cirques into the old surface. 



extent and comparative recency of the uplift which has renewed the 

 cutting power of the Grand River. Increased erosion on the softer 

 sedimentary strata east of the Front Range granite area has lowered 

 the Great Plains immediately adjacent to the foothills, thus further 

 uncovering and sculpturing into hogbacks the more resistant beds 

 of the steeply upturned sedimentary series of the foothill belt. 

 The map of the Livermore Quadrangle suggests that there were 



