398 Colorado River of the West. 
selves to any geologist who should traverse the table-lands west of the 
Rocky mountains, or should receive an accurate description of them from 
others. 
The first of these questions is: To what cause is due the peculiar topo- 
graphical features of the surface of the table lands—where the different 
formations succeed each other in a series of steps, which generally present 
abrupt and wall-like edges—the more recent strata occupying the highest 
portion of the plateau? The other has reference to the place and extent 
of the dry land, of which the erosion furnished the sediments now com- 
posing the table-lands. if 
The first of these questions belongs appropriately to the subject of sur 
face geology, and will be referred to again. I may say here, however, 
that, like the great cafions of the Colorado, the broad valleys bounded by 
high and perpendicular walls belong to a vast system of erosion, and are 
wholly due to the action of water. Probably nowhere in the world has 
the action of this agent produced results so surprising, both as 
to that embodiment of resistless power—the sword that cuts so many 
ogi ots—voleanic force. The Great Cafion of h 
would be ered av u nt i e earth’s crust, and the 
The opposite sides of the deepest chasm showed perfect correspondent” 
of stratification, conforming to the general dip, and nowhere displaceme? 2 
and this bottom rock, so often dry and bare, was perhaps pend i poe 
. 
ting the Palzozoic age, Dr. Newberry remarks: - 
“The question of the origin of the sediments composing the stratific 
rocks of the table-lands of the Colorado can scarcel y be intelligently bo 
cussed till we know more than we now do of the geology of a ; of 
ying north of the Colorado, and of the 
| Tnan attempt to restore the physical geography of this region 
during ‘fe P 
broad and compound b 
