But the field was still new to the world and to science.

Quite appropriately, one of the highest peaks from which the Colorado draws its first waters, is now distinguished by the name of the earliest scientific observer to enter its basin.

Fremont came up the North Platte and the Sweetwater branch, crossing (1842) from that stream by the South Pass thirty-four years after Andrew Henry had first traversed it, over to the headwaters of the Colorado.

The ascent to South Pass is very gradual, and there is no gorge or defile.

The total width is about twenty miles.