GEOLOGICAL SUKVEY OF THE TEERITOEIES. 333 



tion of bitumen wliieh they contain, thougli mostly barren of fossil re- 

 mains. 



From Rawiings, still on the line of the Union Pacific Eailroad, the 

 Lignitic formation soon comes up, bordering the belt of the Cretaceous 

 which passes southward, and at Separation, ten miles west, a bed of 

 coal, reported 11 feet thick, has been opened and then abandoned for a 

 time on account of the difficulty of mining it, and of its distance from 

 the railroad. At Creston, fourteen miles farther west, no coal has been 

 found exposed, but a bed of lignite has been passed by a boring at 83 

 feet from the surface. The coal is reported 4 feet thick and of good 

 quality. Here the strata are nearly horizontal, and it is probably the 

 same bed which thirteen miles farther west, at Vv^ashakie Station, is 

 indicated by a boring as beiug oi feet thick at 120 feet from the surface. 

 As Washakie Station is 333 feet lower than Creston, this difference, wil^h 

 that of the distance from the surface to the coal, would indicate a dip 

 to the west of about 30 feet per mile. The records of this last boring, 

 which I owe to the kindness of Mr. John Denover, station-agent, further 

 indicate a stratum of red paint 20 inches thick at 180 feet, and then a 

 succession of beds of soapstone alternating with beds of white sand- 

 stone to 675 feet, where water was obtained. The beds here called 

 soapstone did offer to the bore as much resistance as, if not more than, 

 white sandstone. Though no positive evidence can be drawn from these 

 records, it appears, however, that the thick formation of white sand- 

 stone, interlaid by beds of hard clay-shale, represents the sandstone 

 formation of the Lower Lignitic. Generally springs, mostly of mineral 

 water, flow out at its base, near its line of superposition to the compact 

 and impermeable clay-beds and black shale of the Upper Cretaceous.* 



§ 7. Black Butte to Eock Spring. 



In following the railroad from Black Butte westward, the Lignitic 

 formation, already seen at the surface of the country from below Bitter 

 Creek Station, forms an irregularly broken ridge, whose general dip 

 toward the east is varied by low undulations. In that way the measures 

 slowly ascend to Point of Eocks, where they overlie the black shale of 

 the Cretaceous iS"o. 4, there constituting the axis of an anticlinal, which 

 is cut, below Point of Eocks, by the meanders of Bitter Creek. The 

 counterface of the axis appears westward in corresponding strata after 

 passing Saltwell Valley, and hence the dip to the west brings to the 

 surface the upper strata of the Lignitic at Eock 'Spring. The section of 

 the measures is perfectly clear and exposed in its whole length. At 

 Point of Eocks, and near the highest part of the anticlinal axis, the 

 Cretaceous strata are exposed 80 feet in thickness, immediately and 

 conformably overlaid by 185 feet of the Lignitic sandstone which from 

 its base bears fucoidal remains. It has moreover the composition, mode 

 of disintegrations, &c., remarked already in the same formations at the 

 Eaton. East of the station, 25 feet above the base of this sandstone, 

 there is a bed of coal 8 feet thick. Parfher east, at Hallville, a Lignitic 

 bed, overlaid by shales where are imbedded a quantity of fossil-shells, 

 is worked near the level of the valley at a short distance from the rail- 

 road. At Black Buttes a bed of lignite is worked, too, above the Eocene 

 sandstone, as indicated by the following section taken from the railroad, 

 half a mile east of the station : 



* For further details on the geology of that barren and wild country, see Dr. F. V. 

 Hayden'3 Keport, 1870, pp. 139, 140 



