55 



Purcell range was built prior to tlie Rockies, and that 

 the two ranges are structurally separated by the Rocky 

 Mountain trench. 



Miles and ANNOTATED GUIDE. 



Kilometres. 

 (From Dunmore.) 



263-7 m. Elko. — Altitude 3,040 ft. (924 m.). On the 

 421-9 km. hill to the north is exposed a section showing 

 the transition from the Cambrian (?) quartzites at 

 the base of the hill to the lower Palaeozoic lime- 

 stones at the summit. Elk river, which above 

 this point had been flowing in a hanging valley, 

 now swings to the southwest, and enters a 

 narrow canyon carved into the flat-lying Cam- 

 brian, argillaceous quartzites, and joins Koo- 

 tenay river at grade about 15 miles, (24 km.) 

 southwest of Elko. At Elko, which is situated 

 on the extreme western edge of the Rocky 

 Mountain system, the Kootenay River valley 

 is entered. The railway pursues a north- 

 easterly course across this valley, whose floor 

 is covered with stratified Pleistocene gravel, 

 sands, and silts. A knob and kettle topography 

 is a prominent feature of this valley. In this 

 floor covering, the Kootenay river has intrenched 

 itself in a meandering course, whose flood plain 

 is wider than its meander belt. The river 

 itself is crossed just before reaching Wardner. 

 286-7 rn. Wardner. — Altitude 2,434 ft. (740 m.). At 

 461-0 km. the end of the railway bridge over the Kootenay, 

 the Mississippian limestone (Lower Carbonifer- 

 ous) is exposed and contains the fossils enumer- 

 ated on page 5 1 . This limestone is in contact, on 

 its eastern and western boundaries, with the 

 non-fossiliferous Cambrian or Pre-Cambrian 

 argillaceous quartzites. The high range to the 

 east is the western slope of the Rocky moun- 

 tains which rise wall-like to an elevation of 

 nearly 10,000 feet (3,048 m.). They are com- 

 posed of Cambrian or Pre-Cambrian sedimen- 

 tary rocks. From Wardner the railway runs 

 over the Mississippian limestone, which occupies 

 the bottom of the Kootenay valley. From the 

 car the terraces of Kootenay river are distinctly 

 visible. 



