62 DESCUIPTIVE GEOLOGY. 



nearly level grassy j^lain of Laramie sandstone. Still farther southv/ard, 

 the same beds appear to extend nearly to the Cache la Poudre. Along the 

 valley of the river, and upon the adjoining banks, Quaternary beds con- 

 ceal in a great measiu-e the underlying rocks, but the same series of beds 

 would appear to lie upon both sides of the stream. 



On Lone Tree Creek, near Carr's Station, may be seen the grayish- 

 white sandstone, which would appear to be characteristic of certain hori- 

 zons in the Laramie formation. Along Lone Tree Creek, Owl Creek, and 

 still farther eastward beyond the limits of our map, beds of undoubted Lara- 

 mie age form the surface of the plains. In many localities, beds of argil- 

 laceous sandstones and carbonaceous clays, with indications of coal seams, 

 crop out; while on Crow Creek, between 4 and 5 miles from its mouth, 

 where it empties into the South Platte, occurs a thin stratum of coal em- 

 bedded in reddish-gray sandstone, which lies approximately horizontal. So 

 far as known, at the time our parties visited this country, in the summer of 

 1872, no shaft had been sunk in explorations for coal. Since that time, 

 however, numerous openings have been made, which have cut coal seams 

 varying from 2 to 3 feet in thickness, almost always lying nearly horizontal ; 

 but in most cases, the shafts have been abandoned, the coal, besides being a 

 thin seam, having proved to be of little practical value. 



All the specimens of coal which were collected in northern Colorado, 

 from the area under examination, and those which were shown to us from 

 the immediate region, presented the same general characters, mostly jet 

 black, with a bright lustre, when pure, and free from clay. Many of them 

 carry thin films of pyrites. All of them would appear to crumble readil}^ 

 when exposed to atmospheric agencies. 



In regard to the palseontological evidences of the Laramie formation, 

 it may be said that none of the characteristic types of the Fox Hill beds, 

 so abundant all along the base of the mountains, were found by our parties 

 in the upper sandstones. But at several localities forms of marine inver- 

 tebrata, which Prof. F. B. Meek has pronounced as undoubtedly of Cre- 

 taceous age, were obtained from a friable red sandstone which forms the 

 overlying stratum of the Plains. They were found in the high bluff which 



