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COLORADO RIVER BASIN 
Without delay the task was begun, and, contemporaneously with 
the uprising, the stream gradually incised itself into the gigantic 
plateau which was being slowly lifted across its course. It is 
refreshing to the observer to note that no matter how colossal 
the task, the processes of nature never falter in their work. They 
almost seem to know that if they continue unceasingly even 
mountain ranges can be pulled down a grain at a time. And thus 
for past millions of years the Colorado River has been carry¬ 
ing its sediments to the ocean, to the end that sometime in the 
distant future the task imposed upon it shall be completed. 
In order to understand the manner in which the River has thus 
far accomplished its work, one has only to keep clearly in mind 
a few well known geological principles. To begin with: Nature 
everywhere cuts deep stream-channels into lands undergoing 
elevation. This, of course, is brought about by the increased 
velocity and carrying power of the water so effected. Under 
such conditions the work of widening the channel is left almost 
exclusively to agencies other than running water, principally 
wind, frost and daily changes of temperature. Particularly in arid 
climates, the immediate work of running water is confined almost 
exclusively to stream channels and, therefore, to a very small 
fraction of the total area. In the Colorado Basin wind plays 
an indispensible part in disintegrating the formations and in 
carrying the particles into the stream channels where they are 
continued on their journey to the ocean. 
Contemporaneous, therefore, with the uplifting of the Colorado 
Basin, the River largely abandoned its meandering habits and at 
once began to sink itself into the formations freshly exposed to 
its action. While the principal energies of the stream were 
devoted to deepening the channel, the other agencies were grad¬ 
ually widening it, particularly near the top. The incising action, 
however, was so intense that the gorge gradually became increas¬ 
ingly deeper in comparison with its width. But as time went on 
the upper rock members of the valley, each in turn, receded farther 
and farther from the central channel, until the whole affair began 
to assume the form of a giant stairway leading down to the inner 
chasm. This condition still prevails on the northern side of the 
Basin. One may stand at a point of vantage on the Paunsaug- 
