128 GEOLOGICAL SUEVEY OF TEE TEERITOEIES. 



the Sand Hills ou tlie Niobrara Eiver. A close examination of the sand 

 shows, that it is composed mostly of worn particles of quartz and feld- 

 spar. The surface contains little or no vegetation, presenting a peculiar 

 barren appearance, the sand moving readily with the wind. 



Hitherto it has been impossible to color on any geological map the 

 geological formation of any part of this mountain region, and no infor 

 mation has ever been given in regard to the structure of the North Park. 

 It will be impossible even now, with the imperfect topography of any 

 of the maps, to color the geology in detail, bat these explorations will 

 enable a geologist to fix the outline of the formations in a general way 

 with a good degree of accuracy. 



During the summer of 1868 an excitement was created at Laramie 

 City by the supposed discovery of rich placer mines far up in the moun- 

 tains, near the Snowy ranges, to the southwest of the plains. A large 

 party was formed at Fort Sanders, directed by Generals Gibbon and 

 Potter of the United States Army, and accompanied by Professor 

 James Hall of New York, to visifthe region and ascertain the truth of 

 the reports. The time was most favorable, in midsummer, when the 

 mountain vegetation presents a spring aspect. 



Camping with our wagons at the base of the main range of mountains, 

 near the source of the Little Laramie, we prepared to ascend the moun- 

 tains on horseback to the gold mines. We rode a distance of about ten 

 miles before we came, in view of the " diggings," and to reach them 

 made an ascent of about two thousand feet above the bed of the creek. 

 We were then between 10,000 and 11,000 feet above the sea, very near 

 the elevation of perpetual snow, and where frost occurs every night of 

 the year. On the summits of these lofty mountains are some most beau- 

 tiful open spots, without a tree and covered with grass and flowers. 

 After passing through dense pine forests for nearly ten miles we sud- 

 denly emerged into one of these park-like areas. Just in the edge of the 

 forest which skirted it were banks of snow six feet deep, compact like 

 a glacier, and within a few feet were multitudes of flowers, and even the 

 common strawberry seemed to flourish. These mountains are full of little 

 streams of the purest water, and for six months of the year good pas- 

 turage for stock could be found. 



The gold is sought after in gulches, formed by the little streams that 

 flow from the Medicine Bow and other snowy mountains, most of which 

 empty iuto the North Platte. We labored for two days to discover the 

 quartz seams, which we supposed to be the source of the stray lumps of 

 gold, but the great thickness of superficial drift which covers all these 

 mountains concealed them from our view. The gold, as far as known 

 in this district, seems to be confined to the lower glacial drift. That 

 valuable mines will be found in these mountains at no distant day seems 

 very probable. The geological evidence is quite conclusive, and the 

 mountains are a continuation northward of the same range in which 

 the rich mines of Colorado are located. 



Not only in the more lofty ranges, but also in the lower mountains, 

 are large forests of pine timber, which will eventually become qf great 

 value to this country. Vast quantities of this pine in the. form of rail- 

 road ties are floated down the various streams to the Union Pacific Bail- 

 road. One gentleman alone contracted for 550,000 ties, all of which he 

 floated down the stream from the mountains along the southern sideof the 

 Laramie Plains. The Big and Little Laramie, Eock Creek, and Medicine 

 Bow Eiver, with their branches, here literally filled with ties at onetime, 

 and I was informed that in the season of high water they can be taken to 

 the railroad from the mountains, after being cut and placed in the water, 



