F. GEOGRAPHY. 253 



into a broad, barren valley, with only here and there scanty 

 patches of vegetation. Soon after it enters a deep caiion 

 with vertical walls, 1000 feet or more in height, and con- 

 tinues to increase in depth until its junction with the Colo- 

 rado River of the West. The Yam pah or Bear River devi- 

 ates from a westerly course only for a few miles occasion- 

 ally. Like White River, it flows through a plateau country 

 which rises gently from the river, back for a distance of 

 about ei2:ht miles. South of the river lie the Williams River 

 Mountains, which have a gradual slope to the north. Will- 

 iams Fork, flowing from a southeastern direction, joins the 

 Yampah River. West of the junction, the Yampah traverses 

 the country more or less in a caiion, cuts through the Yam- 

 pah Mountains, when it joins witli the Snake River. Tlie 

 place of junction resembles a fine park, surrounded on all 

 sides with eroded terraces and plateau spurs, that rise by 

 steps to the divide on either side. This park is about eight 

 miles in length from east to west. 



After leaving this park, the river enters a huge fissure in 

 the mountains, where it remains until, completing its zigzag 

 course, it joins the Green River in lat. 32 and long. 109 40'. 

 After the junction with the Yampah, the Green River con- 

 tinues in a canon for fourteen miles, when it passes through 

 the picturesque palisades of Split Mountain into an open, 

 broad valley (lat. 40 28', long. 109 15'), from which point it 

 takes a southeastern direction through the Wamsitta Valley, 

 where it unites with the White River. 



Into both the White and Yampah Rivers numerous branches 

 extend from either side, forming deep canons the greater por- 

 tion of their length. We may say, in brief, that the sides of 

 the valleys expand and contract, at one time forming the 

 beautiful grassy valleys which in olden times were celebrated 

 as the favorite w^intering-places for the trappers, or contract- 

 ing so as to form narrow canons or gorges with walls of va- 

 ried height. 



The walls of Yampah Caiion average about 1000 feet, 

 while the mountains, receding to the northward, attain an 

 elevation of 4200 feet, the highest point of the plateau on 

 tlie south side beino; 3400 feet above the river level. 



Of the plateaus between the White and Yampah Rivers, 

 Yampah Plateau is the largest, and occupies an area of 400 



