GEOLOGICAL SURVEY OF THE TERRITORIES. 327 



■water shells — unios of undescribed species. In the inner part of the 

 mine, when the roof has been allowed to come down, many tons of these 

 slates might be collected charged with the shells, still white, and often 

 both valves preserved side by side. The brown sandstones interstratified 

 with the coal-beds contain stems of trees converted into the same rock, 

 and impressions of the leaves — all, however, very obscure. 



Van Dyke. — The next coal mine along the road is known as the Yan Dyke, 

 thirty miles farther west. This is in a hill on the north side of the rail- 

 road track, and so conveniently near to it that the coal is discharged by 

 a chute from the mine directly into the cars. The bed is four and a 

 half feet thick, entirely free from any admixture of foreign substance, 

 except a trifling amount of iron pyrites in thin flakes in the seams, and 

 dips gently to the northwest into the dry, barren hill in which it is 

 found. The roof over it is remarkably smooth and sound, so that all 

 the coal can be taken out clean, and comparatively few props are required 

 for supporting it. This is an important consideration in a country so 

 barren of trees as this Bitter Creek region. No water is met with in the 

 mine, and the bed can apparently be followed over an extensive range 

 northeast and west without encountering any. The mine fronts upon 

 the valley of Bitter Creek toward the south; and in the hills opposite 

 it seems as if the same bed must again strike in. 



The Van Dyke coal and that of Rock Springs, two miles beyond, have 

 the best reputation of any of the Bocky Mountain coals, and this by 

 their analysis seems to be well deserved. These were the only coals 

 that afforded anything like coke by distillation ; and they should give 

 a more concentrated heat than any of the others, showing the best 

 adaptation for metallurgical purposes. 



Bock Springs. — The mines known by this name are two miles west 

 from the Van Dyke bed, and one mile east from the station of the same 

 name. The coal of this locality has been obtained chiefly from a dry, 

 barren knoll of cavernous sandstone, about sixty feet high, situated about 

 fifty rods southeast from the railroad, with which it is connected by a 

 branch track. On the south side — away from the railroad — the knoll 

 ends abruptly in vertical cliffs j and in these near the summit is the out- 

 crop of the coal-bed, and the entrance to the mine. The slope of the 

 strata is north-northwest, which carries the coal-bed under the main 

 track of the railroad ; and as the knoll is now almost exhausted of coal, 

 arrangements have been made for working the bed close to the main 

 road, where also is the village of miners' houses. The bed is about nine 

 and one-half feet thick, but only about seven feet are worked ; for within 

 two feet of the top is a thin seam of slate, that, with the coal above it, 

 makes a better roof than the dry and crumbling slates and sandstones 

 above would make. The coal, like the Van Dyke, is very sound and 

 clean, igniting readily and burning away entirely without crumbling in 

 the fire. The smoke is black, like that of the bituminous coals. The 

 mine is worked by contract — the miners riddling the coal in the mine, 

 and delivering the lump coal only outside for $1 25 per ton. The work- 

 men have evidently been left to their own discretion, without any regard 

 to obtaining the greatest amount of coal the mine should afford. 



The opening by the railroad track is a slope passing under Bitter 

 Creek. This had not in October passed quite through the " rusty " coal 

 into the sounder part of the bed. The mine has to be provided with a 

 steam-engine for pumping and hoisting, and will no doubt be productive 

 in large quantities of excellent coal. 



This vicinity, like most of the Bitter Creek Valley, is deficient in good 

 water ; so that, for about sixty miles east from Green Biver, this has to 



