THE BUILDING OF THE COLORADO ROCKIES 



159 



of the divide in a region of steep-sided peaks and precipitous cirque 

 walls. The bench mark on this summit flat records an elevation 

 of 12,364 feet. Views from the nearby peaks give the observer 

 an excellent idea of this old peneplain. South of the Lyons-Grand 

 River section more of the peneplain is still preserved on the con- 

 tinental divide. The crest of the range from the neighborhood 



Fig. 2. — The peneplain on the continental divide. Looking southeast across 

 Flattop Mountain (12,364 feet) to Long's Peak, a rugged peak carved from an unre- 

 duced remnant rising above the peneplain level. In the immediate foreground are 

 the upper cirque walls of Spruce Canyon. Several other steep- walled cirques head 

 back into Flattop but are barely visible in this view. 



of Arapahoe Peak to James Peak, when viewed from the Windy 

 Gap Ridge west of Granby, presents an almost horizontal skyline 

 whose elevation is shown by the map of the Central City quadrangle 

 to be very close to 12,000 feet. Continuing the vision to the south 

 of the monadnock group comprising James Peak, Mt. Eva, and 

 Mt. Flora, the eye is again impressed by the level sky line which 

 extends onward for many miles with little departure from the 

 12,000 foot elevation. 



