1922] 



EDWARDS, GEOLOGICAL WORK AT GRAND CANYON 



101 



bed of the main river and causes it to descend in a series of very beauti- 

 ful rapids. The great amount of sand and gravel which is carried 

 down by the main stream and washed with considerable force against 

 the boulders, has polished many of them as smoothly as marble, and in 

 some instances has etched upon their surface a very pleasing and in- 

 tricate design. Looking upward as in figure 55, one can see, close at 

 hand, the narrow and enclosing walls of the Granite Gorge, above that 

 the buttes and mesas formed of the Redwall limestone and far away, 

 forming a skyline, is the rim of the canyon itself. 



Fig. 57. — The Tonto Platform, showing the Tonto Trail, Grand Canyon. 



Retracing our steps to Hermit Camp, the party stayed for the night 

 and resumed the journey on the following day, going eastward along 

 the Tonto Platform on what is known as the Tonto Trail. This trail 

 extends for a long distance in the interior of the canyon, and runs 

 parallel to the river, but the ordinarily used portion is confined to that 

 part between Hermit Camp and the Bright Angel Trail, which descends 

 from the vicinity of El Tovar Hotel. This: is a distance of eight miles 

 by the rim road, but the many windings and turnings required in order 

 to cross or to go around the side canyons increase the distance to 

 twenty-four miles by this trail. From this platform, the river is in 



