798 GEOLOGICAL SUEVEY OF THE TEEEITORIES 



mucli interest, I paid considerable attention to that portion of the route 

 up Henry's Forli of the Snake Eiver, over Eaynold's Pass and down the 

 Madison, a route which has recently begun to attract attention, over 

 which we traveled ; i. e., from the vallej^ of Henry's Lake over Eay- 

 nold's Pass, and thence down the Madison Eiver to the Three Forks of 

 the Missouri. The route pursued by our train down the Madison, from 

 the foot of the Middle Caiion, is by no means the easiest route. A rail- 

 road can follow closelj- the bank of the river with little expense from 

 this point to the head of the Lower Caiion at Meadow Creek. 



The valley of Henry's Lake is broad and perfectly level, but very 

 swampy near the lake. A rof^d coming- up Henry's Fork of the Snake, 

 would make a sweep around the lake, keeping at a distance of about a 

 mile from it on the east side. The summit of Eaynold's Pass can be 

 reached by easy' grades of not more than 60 feet per mile, without any 

 cutting. The pass is very broad, with perfectly smooth approaches on 

 both sides. The Madison Valley here is terraced. Froui the head of 

 the pass the level of the river can be reached in twelve miles, at which 

 point the valley contracts by a grade not exceeding 75 feet per mile. 

 The valley is narrow for three to four uDiles, with several spurs crossing 

 it and extending to the river, but which can be avoided by keeping 

 close to the river, which involves some embankment. Below this the 

 valley opens again, with a perfectly level bottom, which extends-to the 

 head of the Lower Caiion, at Meadow Creek, and here the only difficul- 

 ties on this route will be met. The fall of the Madison from the foot of 

 the Middle Caiion to this point averages 23 feet per inile. The Lower 

 Canon is, from information which I have gathered from reliable sources, 

 impassible for a railroad, nearly so, even, for men on foot. To pass 

 around it, the road must cross the divides between Meadow and- Hot 

 Spring Creeks, and between Hot Spring and Cold Spring Creeks, neith- 

 er of them high, but, so far as. I know them, involving grades too steep 

 for a railroad to surmount, except at heavy expense in cutting, as is in- 

 dicated in the elevations and distances on this route given below. The 

 stage-road crosses the divide between Meadow and Hot Spring Creeks, 

 farther up from the mouth, by a better route, but I have no data con- 

 cerning it. Still farther from the river the divide rises higher and more 

 abruptly. 



The elevation of Yellowstone Lake, as well as that of several other 

 points, as determined by my observations this year, will be seen to differ 

 materially from that given in the report of the survey for 1871. This 

 difference arises from the want of a barometric base for the work of 

 1871, the observations being referred directly to the sea-level. In the 

 case of Yellowstone Lake, synchronous observations were taken at But- 

 ler's Eanch, but they were not used as base observations. Making use 

 of these, they give the same result that I obtain. 



For the computation of elevations, Guyot's tables have been used. 



The elevations are given in feet above the level of the sea unless 

 otherwise indicated. 



