6 9 



ing ioo feet (30 m.) in thickness, are to be seen. 

 To the west of the railway, and in most places 

 within a distance of half, a mile, Watson river 

 follows an exceedingly tortuous course from 

 near Robinson to Lake Bennett, a distance, as 

 the crow flies, of about 18 miles (29 km.) For 

 this portion of its course, the river is in most 

 places a slow, deep, sluggish stream. 



Practically the only consolidated rocks that 

 outcrop at all close to the track along this part 

 of the journey constitute a low sharp ridge 

 running along the west side of the railway 5 

 or 6 miles (8 to 10 km.) north of Caribou. 

 These rocks are dominantly Jura-Cretaceous 

 conglomerates and sandstones, and in places are 

 decidedly reddish on weathered surfaces. 



About 10 miles (16 km.) before reaching 

 Whitehorse, Lewes river comes into view, 

 having broken its way through the high moun- 

 tain ridge running parallel to the railway on the 

 east. Five miles (8 km.) farther on, the railway 

 swings close to the river at a point near the 

 head of Miles caynon, and from there a splendid 

 view is afforded of the canyon with its walls of 

 Tertiary basalt showing pronounced vertical 

 columnar jointing. 



During Pleistocene time, the former channel 

 of Lewes river became filled with glacial debris, 

 causing the stream to become diverted from its 

 foimer course. After the retreat of the ice, the 

 river had become superimposed on the basalts in 

 the valley and, in rapidly sinking its channel 

 to obtain grade, produced the famous Miles 

 canyon. In shooting this canyon and the 

 Whitehorse rapids below, many men have lost 

 their lives, particularly during the early days 

 of the Klondike excitement and before the 

 construction of the railway. 



From the head of the canyon, the railway 



descends with a steep grade to the town of 



Whitehorse which is situated at the head of 



no m. navigation on Lewes river, the main tributary 



176 km. of the Yukon. 



Whitehorse — Altitude 2,083 ft. (633 m.) 



