T.ADD.J GEOGRAPHY GENERAL FEATURES. 437 



as rough a one as to the south. The divide at the head of the Muddy 

 Creek of Middle Park is very low, but 8,772 feet elevation ; while at 

 no poiut is the Park range lower than 9,000 feet, except where the 

 caiion of the Grand cuts through it. So, if this canon did not exist, the 

 entire drainage of the Middle Park would flow through the Muddy Pass 

 into the North Platte River. 



The main spurs or ridges between Park View Mountain and the Park 

 range, which, to the south from the divides between the Troublesome, 

 the west fork of the Troublesome, and the Muddy, have a northwest 

 and southeast trend parallel to the range. 



Considering the country west of the Park range as a unit, the main 

 topographical feature is the White River plateau, a lava capped mesa, 

 irregular, and cut by deep canons and valleys, which olten nearly sub- 

 divide it. 



This western district comprises about three thousand five hun- 

 dred and twenty square miles, and the drainage is divided into three 

 systems, the Yampah or Bear River, the White, and the Grand. The 

 Yampah drains nearly the northern half of the district, the White the 

 western central, about one-quarter, and the Grand the southern third. 



The Yampah has a northeasterly and northerly course from its source 

 on the eastern side of the mesa, which, situated in the center, is a point 

 from which the drainage radiates, tdl it reaches the Park range within 

 a mile of our north line, when it makes a sharp bend and holds a course 

 due west till it joins the Green River. 



The White River drains the heart of the plateau, and the main stream 

 has its source in Trappei's Lake, which nestles in one of the deep-cut- 

 ting valleys close under the cliffs. The South Fork of the White, head- 

 ing near Shingled Mountain, cuts a deep precipitous canon through the 

 center of the plateau. 



The Grand River, which issues from the Middle Park through the 

 cafion in the Park range, flows through a broken series of gorges for 

 ninety miles, opening out occasionally into a small valley of from one to 

 five miles in length, but tor the greater part of its course in rough, often 

 impassable canons. The Eagle flows through an open sage-brush val- 

 ley lor twelve miles and then through a narrow valley for five miles 

 before it joins the Grand. 



From the White River plateau, the surface of which is irregularly 

 rolling, there rise a number of isolated mountains, Shingled Mountain, 

 station XLI, and point 17-XLT, from 500 to 1,000 feet elevation above 

 the general surface. These made excellent topographical stations. The 

 eastern edges of the spurs, as well as of the main plateau, are the high- 

 est, sloping on the west to the edges of the mesa, and falling off on all 

 sides with abrupt, high cliffs, to the long, sloping spurs below. To the 

 east there are a number of ridges partially detached from the plateau, 

 and the highest points of these are the mountains that show so promi- 

 nently from the east, Dome Mountain and Mount Ornuo, which stand 

 just south and north of the head of the Yampah, the highest mouutains 

 west of the Park range in this district. 



The Dome Mountain ridge is entirely separated from the plateau, and 

 the Mount Ornuo mass is connected by a narrow wall of rock, some- 

 what higher than the plateau at either end, in places but 3 feet in width, 

 and a sheer precipice on both sides of frotn 700 to 800 feet. To the 

 north lies the valley of the Williams Fork, a large tributary of the Yam- 

 pah ; to the south the headwaters of the Yampah itself. Standing near 

 the center of this wall, which is 125 feet in length, with outstretched 

 arms, and dropping a stone irom each hand simultaneously, they fall 

 for 100 feet before touching the sides of the cliffs. It was very much 



