526 REPORT UNITED STATES GEOLOGICAL SURVEY. 



These beds I have referred to the Green Eiver Group. They are ex- 

 posed on the right hank of the Big Sandy, just above the mouth of the 

 Little Sandy. The course of the Big Sandy from this i)oiDt to the Green 

 is south and southwest. It is in a low caQon without bottom-land or 

 groves, and is a shallow, rather sluggish stream, with a sandy bottom. 

 The rocks between the Big and Little Sandy are probably the same as 

 those given in the section above. Farther east, however, there are 

 higher beds which form high table-like buttes, resembling Pilot Butte, 

 that forms so prominent a landmark farther south. 



As we approach the mountains the valley of the Big Sandy improves 

 somewhat. It is wider and has better grass, but the siuTounding country 

 is still sage-covered and monotonous. Variegated beds are seen resting 

 on the granite. The following is a section made between camps 4 and 5 : 



Section No. 2. 

 Base. 



1. Greenisli gray and pinkisli arenaceous bad-land beds 100 feet. 



2. Yellowish marls? and sands 200—300 feet. 



3. White sandstones, shales and marls? with variegated argilla- 



ceous and arenaceous beds at the top. These were noted from 



a distance ? 



300 H 400+ feet. 



The strata incline about five degrees from the mountains and are prob- 

 ably of the Wahsatch Group, although the upxDcr layers resemble the 

 lower beds of the Green Eiver Group. These Wahsatch sands rest di- 

 rectly on granitic rocks, as already stated. The sources of the Big Sandy 

 are in the district surveyed by the Sweetwater division, and will be 

 found described in Dr. Endlich's report. 



JSfew Forlc of Green River.— On the southwestern slopes of the Wind 

 Eiver Mountains and in the adjacent foot-hills a number of beautiful 

 clear streams have their sources. These streams are all swift and ob- 

 structed by bowlders. Along their courses are abundant evidences of 

 glacial action, and long moraines extend from the mountains bordering 

 them as far as the edge of the basin. Glacial lakes also are numerous. 

 The creeks after emerging from the foot-hills form the New Fork of 

 Green Eiver before joining the main stream. Our work during the 

 season did not extend into the foot-hills, so that the description of the 

 moraines and other glacial phenomena will have to be reserved for an- 

 otlier report. The region through which the branches of the ISTew Fork 

 flow may be described as a " bad-land " country. This is owiug to the fact 

 that the rocks are mainly of Wahsatch age, especially those close to the 

 mountains. As we leave the hills, cappings of Green Eiver shales ap- 

 pear. There is good grass throughout, and antelope were abundant 

 when we went through the country in June. Some of the valleys are 

 broad and well suited for agricultural purposes, were it not for the great 

 elevation. Willows are found along the streams, but timber is scarce 

 outside of the foot-hills. The stream bottoms are very marshy and the 

 creeks obstructed by beaver-dams. The northern rim oi' the Green 

 Eiver Basin is beyond the limits of oiu* district and will be the field for 

 investigation in 1878, and to the report for that year, when published, 

 the reader will have to refer for additional information in regard to the 

 sources of the New Fork of Green Eiver. 



Green Biver. — Green Eiver has a length of about 116 miles in our dis- 

 trict. In the northern portion of the basin beyond our district the rocks 

 are of Wahsatch age along the course of the river. Below the mouth 

 of Lead Creek, Green Eiver beds are seen capping me»a-like buttes. As 



