Jolin JVcslcy PoivclL— Merrill. 329 
Pike's peak and mount Lincoln. After the breaking up of 
the party at Denver, major Powell and his wife, who had 
accompanied him/ visited Middle park of Colorado and con- 
tinued their explorations until snow interfered. 
In 1868 Powell organized a party for the purpose of a 
second expedition into Colorado, finally going into winter 
quarters on the White river. During this trip he made im- 
portant studies in high altitudes, ascending Long's peak for 
the first time and traversing a considerable portion of the 
mountain system of Colorado." 
In the summer of 1869 he organized an expedition for the 
purpose of exploring the Grand Caiion of the Colorado itself, 
a region up to this time almost wholly unknown and con- 
cerning which there were many vague and often wild rumors. 
The party, consisting of eleven men with four boats and pro- 
visions for ten months, started on its voyage on ^lay 24 and 
emerged from the mouth of the Grand Canon August 29 
following, having made a journey of nearly 900 miles and 
one which has been described as unequaled in the annals ot 
geographical exploration for the courage and daring dis- 
played in its execution. The immediate geological results 
of this trip were very slight. Nevertheless, the prestige gained 
was such as to be of great benefit to Powell throughout his en- 
tire career. 
Explorations of the caiion and adjacent regions were con- 
tinued during 1870, 1871, and 1872, the results being pub- 
lished in 1875 under the caption of Explorations of tlic Col- 
orado River of the West and its Tributaries, in form of a 
quarto volume of nearly 300 pages. It was in the second 
part of the report, relating to the physical features of the 
valley of the Colorado, that Powell called attention to the fact 
that the Uintah canons were gorges of corrosion and due 
to the action of rivers upon rocks which were undergoing 
gradual elevation. As he expressed it, the river preserved 
its level, but the mountains were lifted up, as the saw re- 
volves on a fixed pivot, while the log which it cuts is moved 
along, the river being the saw which cuts the mountain in 
two. This, it will be remembered, was essentiallv the idea 
advanced by Hayden with reference to the canons of the 
Yellowstone, Aladison and Gallatin mi his rei)ort on the geol- 
