122 LINE FROM BASE OP THE MOUNTAINS TO PUGET SOUND. 



valley. At several points on the route the rocky hill-sides crowd upon the river, and all deep 

 cutting will probably expose the rock, apparently mostly species of limestone or trap ; but the 

 valley is wider than the valley of Blackfoot river, or of Bitter Root river soon after its junction 

 with the latter stream, and has a general width of two or three miles. The descent of the valley 

 has an average rate of eleven feet per mile. 



The greatest gradients of the railroad would not exceed fifteen or twenty feet per mile. After 

 passing from the valley of the Jocko to that of the Flathead, it would follow the hills on the left of 

 that stream to a point some miles above its junction with the Bitter Root; then crossing the 

 former, it would follow the right bank of Clark s fork as far as Big Rock. The course then 

 may either be on the right bank the whole distance to the lower extremity of Pend d Oreille 

 lake, or it may cross to the left bank at Big Rock, and recross to the right bank at the Cabinet 

 mountain; or, continuing on the right bank to the Cabinet, some twenty miles above Lake 

 Pend d Oreille, where the river is compressed between walls of solid rock about one hundred feet 

 high, and where the river could readily be spanned by a single arch, it could then cross the river 

 and continue down on its left bank. After reaching the Pend d Oreille lake it could readily skirt 

 the eastern and southern shore, until it reached a southern prolongation of the lake, which 

 extends about twenty-five miles in the direction of the Coeur d Alene mission, and from that 

 fact is called the Cceur d Alene bay. From the upper end of this bay to the Coeur d Alene 

 lake there is said to be a very gentle rise, and a divide so low that it might readily be passed 

 over by a traveller without notice. From the Cceur d Alene lake to the valley of the Spokane 

 there is a good natural, almost level grade. 



The Cabinet mountain might require tunnelling for three hundred yards, fifty per cent, rock, 

 basalt trap; though, by a careful adjustment of the line of approach, tunnelling may be dispensed 

 with without involving a grade greater than forty feet. Both Clark s fork and the Pend 

 d Oreille lake are subject to freshets, fifteen feet being about the difference of level between high 

 and low water marks, which would make it necessary that the road should keep the sides of 

 the hill, or that high embankments should be used. 



The summit separating Clark s fork and Spokane river, and the summit of the Great 

 Spokane plain, are both about eight hundred feet above the level at which these two rivers are 

 crossed. The opportunities afforded for side-hill location prevent the use of objectionable 

 grades. 



The mountain region ends near the crossing of Spokane river. 



The earth excavation and embankment will, throughout this section, be large in amount, and 

 expensive. The very best quality of material for a durable road-bed is met with all along the 

 line. The hill-sides discover the disintegrated fragments of the different rocks, and the bottom 

 lands of the rivers afford abundance of gravel for a road passing through them. With the general 

 character of the excavation, and with the opportunities afforded for good ballasting, the road-bed 

 of this section may be of a superior quality. 



In all the mountain valleys, the deep side-hill cuttings will frequently expose the rock, and the 

 bulk of the rock excavation in the entire railroad route will be in this section. The tunnel al the 

 Rocky mountain divide will probably be through solid rock, and it is possible that one or two 

 small tunnels may be required at other points. 



The approaches to the tunnel at the Rocky mountain divide can be made with a grade ot 

 forty feet per mile, and an undulating grade of forty to fifty feet will be required throughout 

 Blackfoot River valley. The ascent from Blackfoot river to the summit divide, between the 

 Bitter Root and Jocko rivers, can be made with a fifty-feet grade, and with great care in the 

 location the descent westward can be made with a sixty-feet grade. This declivity of sixty feet 

 per mile is the highest required in all this section, and in a mountain country cannot be considered 

 a high grade. On this inclination a train can descend with safety without the application of 

 its brake, and without the use of its motive power ; so that while there is a loss of power in the 



