ROUTE NEAR THE FORTY-SEVENTH AND FORTY-NINTH PARALLELS. 43 



the east,) two passes in the Rocky mountains, in latitude 46 30 , were explored. They are 

 sometimes called the Northern and Southern Little Blackfoot Passes, but named in Governor 

 Stevens s map as the Hell-Gate Passes. They connect between the waters of the Little Black- 

 foot and Prickly-Pear creeks. 



South of these, in latitude 45 45 , another pass was examined, called the Hell-Gate Pass. 

 It connects the south fork of Hell-Gate with a branch of Wisdom river. And still further 

 south, in latitude 45 38 , another pass, called the Big Hole Mountain or St. Mary s Pass, was 

 explored, connecting the waters of St. Mary s river with a fork of Wisdom river. These last 

 four passes are all reported as probably practicable; but as the southern Little Blackfoot, Hell- 

 Gate, and St. Mary s Passes received no instrumental examination, as the last-named is out of 

 direction, and the two former involve a considerable detour from the route of the Missouri, are 

 approached with difficulty, and will only become important should a good route or routes be 

 found through the Black Hills to the Mississippi, it is unnecessary to note them further. The 

 profiles of the northern Little Blackfoot with its approaches from the Missouri, of the valleys of 

 the Little Blackfoot and of part of the Hell-Gate river, were determined by Mr. Tinkham, his 

 instruments consisting of a barometer and pocket-compass. 



The approach by this route is over a broken region of country, and a better approach, it is 

 thought, will be found north of the Missouri, nearer the base of the mountains, along the line 

 examined by Lieutenant Mullan. The elevation of the summit is 6,250 feet; a tunnel of two 

 miles will be required. The eastern approach is estimated practicable with grades of fifty or 

 sixty feet per mile, and the western descent with a grade of thirty feet to the mile. A thorough 

 examination of this route is recommended in connexion with the other passes in this vicinity. 

 It is unnecessary, therefore, to consider it further, since the data are still too imperfect to 

 enable us to form certain conclusions. 



Three passes through the Bitter Root mountains were explored ; a fourth was subsequently 

 examined,, but has not yet been reported upon ; a fifth pass, the northern Nez Perces, it was 

 not considered necessary to examine. 



The passes reported upon are that of Clark s fork, which has been adopted as being the 

 least difficult; the Cceur d Alene Pass, by the Coeur d Alene Mission, and the southern Nez 

 Perces trail. Beginning at the south, the southern Nez Perces trail, leading from the head of 

 St. Mary s river to the head of a tributary of the Snake river,, (the southern fork of the Columbia) 

 was examined by Mr. Tinkham, in the latter part of November and first half of December; 

 his instruments were a barometer and pocket-compass until the former was cached. From the 

 great height of the summit, 8,000 feet, and the great depth of snow so early in the season, 

 it is not necessary to consider this pass. It is probably impracticable. 



The northern Nez Perces trail is reported to be of the same character. 



The Coeur d Alene Pass, leading from the Bitter Root near its junction with the Flathead 

 to the Spokane river, if found to be practicable, would give a route to Wallah- Wallah seventy 

 miles shorter than that by Clark s fork; but as no instruments for measuring vertical or hori 

 zontal distances were carried with the party that examined this route, its practicability cannot 

 be considered established, but merely such information gained as serves to show that it is 

 probably practicable, and that an instrumental profile should be taken. 



The pass of Clark s fork formed by the passage of the river through the Bitter Root mount 

 ains, along which the main party travelled, is practicable. 



It will be noticed that the passes of Lewis and Clark, and Cadotte, give the most direct route 

 from the line east of the Rocky mountains to this pass. 



We will now return to the line of the main party at Hell-Gate, the termination of the Black- 

 foot valley. From this point two lines were examined to Clark s fork. One follows the valley 

 of the Bitter Root to Clark s fork ; the other crosses a dividing ridge to the valley of Jocko 

 river, keeping along this stream to its junction with the Flathead, which it then follows to 

 Clark s fork. 



