SURVEY OF THE COLORADO OF THE WEST. 
23 
flood storms were raging along its course the adjacent country would be 
washed down simultaneously with the deepening of the channel, but the 
conditions for the precipitation of moisture are such that the river cuts 
its gorge much faster than the adjacent country is degraded ; there is 
more through erosion than lateral wear, and the canons mark the differ- 
ence between the progress of the general erosion by rains, and the prog- 
ress of the erosion by rivers. In this way the Colorado has cut along 
its course, for a thousand miles, a series of narrow, winding gorges. The 
Rio Virgen Kanab, Paria, San Rafael, and many others on the west, 
Diamond, Coanine, Flax River, San Juan, and many others on the south 
and east, have cut tor themselves narrow, winding gorges in the solid 
rock. 
f 
Every creek entering a river runs in a canon ; every brook tributary 
to a creek bas cut a canon ; every rill, born of a shower and born again 
of a shower, and living only during these showers, has cut a narrow, 
winding gorge through the solid rock, so that the whole of this region 
is traversed by a labyrinth of canons. 
A\ liile the amount of this river erosion is so great as to almost stag- 
ger belief, it represents but a small part of the total amount of erosion 
exhibited. There are places where by general atmospheric agencies not 
less than 27,000 feet of beds have been stripped from the country, and 
all this since the sea last retired. We cannot suppose that there is any 
part ot the country where there has been no erosion, but there are dis- 
tricts where there has been 27,000 feet less than the maximum. Why 
more in some places and less in others ? This has been a very interest- 
ing problem, and for its solution we have accumulated many facts. 
A glance at the map reveals the fact that the contours of this region 
are angular ; canons whose walls are everywhere abrupt, long lines of 
cliffs, bold escarpments forming difficult, and in some places impassable 
barriers to travel, benches, mesas, and plateaus that terminate in escarp- 
ments. Rounded hills and gentle valleys are rarely seen. The condi- 
tions under which corrugation, erosion, and eruption have produced 
these wonderful and gigantic topographic features have been the sub- 
ject of much study. 
I cannot here give the results of these studies, although the theme is 
greatly attractive, but I will briefly state one conclusion at which we 
have arrived. The displacements marked by the folding and faulting, 
the erosion and the eruptions, were simultaneous ; they began at about 
the same time, and have all continued until a very recent period, and 
probably are still in progress. 
GEOGRAPHIC DISTRIBUTION. 
In a region of country in many places of naked rock and everywhere 
exhibiting escarpments of great magnitude it is possible to trace with 
accuracy the geographic distribution of the beds, and this has been 
done with such care that we shall be able to indicate with minute- 
