THE SANTA FE ROUTE. 129 
features. From Grandview Point there is an extended view to the 
- east and northeast, to the point where the canyon of the Little Colo- 
rado comes in: A wide area in the lower part of the canyon in this 
district is occupied by rocks of the Chuar and Unkar groups. 
If the observer is impressed by the long time required for the exca- 
vation of the Grand Canyon in the slowly rising plateau, let him con- 
sider also the time required for the accumulation of the sediments in 
the many thousands of feet of rocks in the canyon walls. He may 
reflect also on their vast area, for they underlie not only the plateau 
he sees, but also a large part of our continent. An inch of the lime- 
EAST , : WEST 
eS 
ee ee 
Seeger acer net en tee Vie See wens nee Sate ian et arene a SE 
i TapeONeS SES WiC Se Ee ee eare: IaSnen eres Son a oe 
Mibes | Se eS 
limestone 4 —— ams mae mmc Spin wen pe 23.¢-- Sith ptt 
675 feet ‘a ee Be many Bi a a : am ea = ne Soa sae oe 
——— pre eneteneay LET : SSOP. Soe a ee 
bueaniia ee ee See 
in 
sandstone 
Srey Safe 
Supai red shale 
and sandstones ¢ 
120 feet 
Redwall 
limestone J 
S50fect 
Shale of 
Tonto group 
ns of 
a] 
« 
FiguRE 29.—Section of rocks exposed on Bright Angel trail, Grand Canyon, Ariz., showing relatio 
fault. and th ray et . + PR eRe ee logi = ee (brass cap. 
above sea level). Were: 3 ee tee 241 pil ee ee ees és: “ 7s p 
at this place, for gene lly £t. Onn Sank nisee nf - 
hatch 
z 
Stone required many years for its deposition, the shale was mud 
brought from distant hills by turbid streams and spread in thin 
layers, and the sands were deposited by streams or spread on beaches 
far from their original sources in the rocky ledges of the higher lands. 
It should be noted also that in the canyon section are lacking the 
rocks which represent a large part of geologic time in other regions. 
A very long time was also required for the deposition of 12,000 feet of 
the Unkar and Chuar groups and the planation of their surface and of 
the granite surface on which they lie. Probably this required as 
