134 GEOLOGICAL SUEVEY OF THE TERRITORIES. 



streams that flow into the Missouri and Yellowstone Rivers filled with 

 the leaves of the cottonwood and elm in a perfect state of preservation, 

 and had the conditions been favorable for compacting these sediments 

 into rocky layers, the geologist might have split them open with his 

 hammer, and revealed the leaf impressions as perfectly preserved in 

 every part as if they had been carefully pressed in a lady's herbarium. 

 The traveler will find it profitable and instructive to remain at this 

 locality a day. 



The coal is not confined to the neighborhood of the road. It crops 

 out in many localities for twenty or thirty miles on either side, so that 

 we see there is an abundant supply of fuel stored away for future use 

 beneath this apparently barren surface. When we reflect that nearly 

 all the wood or timber that is used along the line of the road has to be 

 transported a distance of twenty to forty miles, and that even this scant 

 supply will be exhausted within a few years, we shall at once arrive at 

 the conclusion that the future success of this great thoroughfare is 

 entirely dependent on the supply of mineral fuel, and that its importance 

 for all time to come cannot be too highly estimated. 



The coal formations extend along the line of the road to St. Mary's 

 Station, a distance of twenty-five miles west of Carbon ; from thence to 

 Rawlins's Springs, about thirty miles, the road passes over strata which 

 are mostly of cretaceous age. To the geologist this entire region is one 

 of great interest. Even up to the present time it is invested with much, 

 obscurity. Probably no rocks older than cretaceous or tertiary occur ; 

 but the beds are so complicated by the forces that have elevated the 

 neighboring mountain ranges that it is difficult to unravel their rela- 

 tions. 



Soon after leaving Carbon we pass through several cuts which show 

 the strata, sometimes inclining nearly west, and soon again in the op- 

 posite direction. We seem to be continually passing across a series of 

 anticlinal and synclinal axes. Just before reaching the North Platte 

 Biver we pass along the valley of one of the most remarkable anticlinals 

 in the West. On either side of the road the rusty-gray sands and 

 sandstones incline at an angle of 10° to 15°. The strata rise like walls 

 on both sides to the height of seven hundred or eight hundred feet in 

 graduated ridges or steps. I have been informed that thin beds of coal 

 have been discovered within a few miles of Fort Steele ; if this be so, 

 they must occur high up on the summits of these ridges. Near the 

 bridge over the North Platte the black, plastic clays of the lower creta- 

 ceous are distinctly seen, but following up the exposed edges of the 

 inclined ridges we find an oyster and an Inooeramus which are peculiar 

 to the upper cretaceous beds. Passing up still higher, we shall dis- 

 cover thin layers made up wholly of a small species of oyster, which 

 seems to be characteristic of what I regard as transition or beds of pas- 

 sage between the strictly marine sediments of the cretaceous era, and 

 the brackish and the fresh water which characterize the tertiary period. 



We can see here a marked instance of a valley of erosion, or a long 

 natural opening, as if prepared in ages past for the passage of the road. 

 We can reflect with what ease comparatively it has been constructed 

 across what would seem to be an impassable country, by following the 

 water-courses and their valleys of erosion, admiring the energy and 

 consummate skill of the engineers who first located the road through, 

 this wild and rugged region. 



We have not alluded to the scenery in this vicinity from the fact that 

 to the ordinary traveler there is little that is attractive. To most 

 persons the whole country would appear like a barren waste. But if 



