SAGE CREEK — NORTH FORK OF THE PLATTE. 243 



wagon or railroad, has thus been traced, presenting fewer obsta- 

 cles to the construction of either than almost any tract of the 

 same length in the country. The grades will be easy, the bridg- 

 ing comparatively light ; and, with the exception of the crossing 

 of the valley of the Muddy, where a long and heavy embankment 

 may be required, the cuttings and fillings will be entirely within 

 moderate limits. In no case will an inclined plane be required ; and 

 the route is more than usually free from the objection of high and 

 narrow canons, liable to be filled up or obstructed by snow during 

 the winter. 



Saturday^ September 21. — Morning clear and bright. Ther. 

 at sunrise, 35°. Ice formed in the buckets during the night. 

 Passing down the right bank of the little drain upon which we had 

 encamped, we encountered the usual impediments from thick arte- 

 misia, and numerous little gullies, many of which were deep and 

 difficult to cross. To avoid them, we turned more to the south, and 

 crossed Sage Creek, an affluent of the Platte, about four miles 

 above its mouth. The water was eight feet wide, and three or 

 four inches deep, with a free current, and vertical clay banks. 

 This part of the route was over a sand and clay soil, denuded of 

 vegetation, and strewn over with black schorl gravel, and an im- 

 mense quantity of white quartz pebbles, in angular fragments, 

 that did not seem to have been water-worn. 



After the crossing of Sage Creek, upon approaching the Platte, 

 we encountered many ravines coming down from a ridge on our 

 right, the intervening ground being washed almost entirely bare of 

 grass or vegetation of any kind. In many places the surface of 

 the ground was covered with small broken fragments of crystallized 

 sulphate of lime, of a rich brown colour, mostly as clear as mica, 

 (for which, indeed, it was at first mistaken,) and many specimens 

 were perfectly transparent. Large quantities of pure white quartz 

 gravel, also, were brought down from the hills, and lay mingled 

 with the gypsum. 



After a march of sixteen miles, we encamped on the left bank 

 of the North Fork of the Platte, in a lovely bottom, amid picturesque 

 groves and clumps of gigantic cotton-woods. The ground was 

 covered with a luxuriant growth of nutritious grasses, among which 

 buffalo-grass was quite abundant. 



In this region the bottom land is principally confined to the left 

 bank, and is from a quarter to half a mile in width. On the right 

 bank are escarpments of rock a hundred and fifty or two hundred 



