ison.] 41 [iiiiydeii. 



are mostly fresli water and hold a nearly horizontal position. West of 

 Bitter creek we get again upon marine tertiaries dipping 3o to 6^ 

 nearly east. We have therefore between Rawling's Springs and Green 

 river a sort of synclinal basin, the marine tertiary dipping west about 

 10° on the east side, and the same marine beds inclining east 3° to 6° on 

 the west side ; while at Table Rock, Red Desert, and Washakie, a con- 

 siderable thickness of purely fresh water beds are filled with shells of the 

 genera Pal'u4'ina, TJnio, Melania, &c. 



Table rock is a square butte lifting itself about 400 feet above the 

 level of the road, composed of the beds of a sandstone which in many 

 instances is little more than an aggregation of fresh water shells. 



After leaving Bitter Creek Station the hills approach nearer to the 

 road and show the characteristic features of the marine tertiary again. 

 "Seams of coal appear in many places, while yellow arenaceous marls, 

 light gray sand with indurated clay beds and more or less thick layers of 

 sandstone occur. The dip varies from 3^ to 6^ east or nearly east. 



At Black Bute Station on Bitter creek, aboiit 15 miles Avest of Bitter 

 Creek Station there is a heavy bed of yellow fei-ruginous sandstone, irreg- 

 ular in its thickness and in part concretionary, and full of rusty concre- 

 tions of sandstones of every size from an inch to several feet in diameter, 

 mostly spherical, and when broken revealing large cavities filled with 

 oxide of iron loam. This sandstone, 1 50 to 200 feet in thickness, forms 

 nearly vertical blufts, and is worn by atmospheric agencies into the most 

 fantastic shapes. Above it are sands, clays, sandstones of every texture 

 and coal beds, one of which, near the summit of the hills, has been 

 burned, baking and melting the superincumbent beds. I found in seve- 

 ral layers the greatest abundance of deciduous leaves, and among them 

 " a fine Palm leaf, probably the same species which occurs in the coal beds 

 on the Upper Missouri, named by Dr. Newbury Gampbelli.- There is also 

 a thin seam near one of the coal seams 'made up of a small species of 

 Ostrea. 



The railroad passes doAvn the Bitter creek valley which has been run 

 through the tertiary beds, and on each side high walls can be seen incli- 

 ning at low angles. As we pass down the A^alley toward Green river, 

 the inclination brings to view lower and lower beds. These are all plain- 

 ly marine tertiaries, while an abundance of impressions of plants are 

 found everywhere. No strictly fresh water shells occur, but seams of 

 Ostrea of various species. There are also extensive beds of hard tabular 

 rocks which would make the best of flagging stones. On the surface are 

 excellent illustrations of wave ripple marks, and at one locality tracks 

 of a singular character ; one looking as if it had been made by a soli- 

 ped. It resembles the tracks of mules on the soft bottom ground. 

 Others seem attributable to some huge bird ; another to some four-toed 

 Pachyderm. I obtained specimens and careful drawings of these tracks. 



In the field report some detailed sections of these tertiary beds will be 

 given. Yet I am convinced that local sections are not very important. The 

 character is so changeable that two sections taken ten miles apart would 



A. P. S. —VOL. XI — F 



