CHAPTER I.
A River Entrapped--Acquaintance not Desired--Ives Explores the Lower Reaches--Powell the Conqueror--Reason for a Second Descent--Congressional Appropriation--Preparation--The Three Boats--The Mighty Wilderness--Ready for the Start.
The upper continuation of the Colorado River of the West is Green River which heads in the Wind River Mountains at Fremont Peak.

From this range southward to the Uinta Mountains, on the southern boundary of Wyoming, the river flows through an open country celebrated in the early days of Western exploration and fur trading as "Green River Valley," and at that period the meeting ground and "rendezvous" of the various companies and organisations, and of free trappers.

By the year 1840 the vast region west of the Missouri had been completely investigated by the trappers and fur-hunters in the pursuit of trade, with the exception of the Green-and-Colorado River from the foot of Green River Valley to the termination of the now famous Grand Canyon of Arizona.

The reason for this exception was that at the southern extremity of Green River Valley the solid obstacle of the Uinta Range was thrown in an easterly and westerly trend directly across the course of the river, which, finding no alternative, had carved its way, in the course of a long geological epoch, through the foundations of the mountains in a series of gorges with extremely precipitous sides; continuous parallel cliffs between whose forbidding precipices dashed the torrent towards the sea.

Having thus entrapped itself, the turbulent stream, by the configuration of the succeeding region, was forced to continue its assault on the rocks, to reach the Gulf, and ground its fierce progress through canyon after canyon, with scarcely an intermission of open country, for a full thousand miles from the beginning of its entombment, the entrance of Flaming Gorge, at the foot of the historical Green River Valley.