PEAiE.1 DESCRIPTIVE GEOLOGY — GREEN RIVER BASIN. 529 



Creek. Station 14 is located on a butte north, of the angle. The fol- 

 lowing is the section at that point: 



Section No. 3. 

 Top. 

 3. Greenish-gray argillaceous sands with bands of yellow sandstones. Near"* 

 the top is a band of limestones. At the bottom are drak-gray sand- 

 stones, weathering into rounded masses that lie scattered about, re- > 2C0 feet. 



sembling grindstones 



2. Greenish-gray and pink marls ? J 



1. Dull brick-red sands and clays with gray sandstones 40 feet. 



240 feet. 



The thickness of these beds was measured with an aneroid barometer. 

 The upper sandstones I have colored as belonging to the Green Eiver 

 Group, and the lower beds as the upper part of the Wahsatch. They 

 weather into characteristic bad-land buttes. To the westward, I think, 

 the Green Eiver beds are in place, and, as seen from the basin rim, pre- 

 sent a bluff edge facing the rim. Between White Clay Creek and the 

 Bitterroot there appears to be a dip to the northeast or north, probably 

 on account of the Carboniferous islands on Feather Creek. Between 

 White Clay and the Green the country is mesa-bke, capped with Green 

 Biver sandstones. This is the result of a northern dip near the mouth 

 of the Piney. In the cauon-like valley east of this mesa the Green is 

 joined by the New Fork, which seems to change the course of the river 

 to the west, so that it comes back to a point about due south of its course 

 before it is shoved to the eastward by Horse Creek. This will be more 

 readily understood by a reference to the map. On the east side of the 

 Green below the mouth of the New Fork, and extending up the latter 

 stream, are high bluffs capped with Green Biver shales with bad-land 

 beds beneath. The capping beds form the surface extending eastward 

 toward the Big Sandy. On the west the bluffs are also well marked, 

 although not so high. Yellow and gray sandstones form the top, with: 

 the pink and red beds beneath. As the Green emerges from this canon 

 it is joined by White Clay Creek, and within a half a mile below by 

 the Bitterroot and the Piney. They join the Green in a wide valley. 

 The White Clay is a thick, white, muddy, alkaline stream in which the 

 water is unfit for drinking. 



Bitterroot Creek is a good-sized clear stream of pure water, rising in 

 the Wyoming Bange, and the Meridional Valley, so frequently referred to. 

 Its general course is southeast through a country of rather uniform level. 

 South of the stream are several isolated buttes of Green Biver beds. 



Piney Creelc drains a larger area of country, north and south, than any 

 of the creeks yet described. Its branches fan out in the country ex- 

 tending northward from Thompson Plateau to a point several miles 

 north of Wyoming Peak. The branch rising in the country adjacent 

 Wyoming Peak and Mount Darby has been named the Lake Branch, 

 from a beautiful lake, about a mile and a half in length, that lies between 

 Mount Darby and Wyoming Peak. The Southern Branch heads opposite 

 the sources of John Day's Biver. There is a smaller Middle Branch ris- 

 ing in the eastern peaks of the range. All the branches have united 

 in one good-sized stream at a point about 12 miles above the mouth. 

 This point is at the northeast corner of a well-marked mesa of Green 

 Biver shales and sandstones. This mesa extends about five miles to 

 the eastward, and is a remnant showing that once the formation ex- 

 tended over all of this region. From Labarge Creek northward: erosion 

 34 GS 



