224 



Kiiomeu-l From Taft station (24-5 mis.) nearly to 



Sicamous the line runs over massive ortho- 

 gneiss generally rich in hornblende and thus 

 contrasted with the dominant biotitic gneisses 

 of the Shuswap terrane. Near Taft the horn- 

 blende gneiss is in sill relation to the rusty 

 (metasedimentary?) schists, but beyond Craigel- 

 lachie (28-5 mis.) it seems to have the con- 

 tinuous character of a batholith or extremely 

 thick laccolith. 



Approaching Sicamous, the train crosses the 

 delta of the Eagle river which has grown so far 

 as to nearly isolate Mara Arm from the main 

 Shuswap lake. 

 45-1 m. Sicamous — Alt. 1,147 ft- (35° m -)- The 



72-6 km. Shuswap lakes have a total length of about 

 150 kilometres. They represent profound changes 

 in the drainage system under the influence of 

 Pleistocene glaciation. Not only were water- 

 divides and stream directions modified at 

 that time; the graded valley-floors were con- 

 verted by Glacial erosion into series of rock 

 basins. Drift barriers have also co-operated in 

 the formation of these fiord-like lakes. The 

 greatest depth recorded for the Shuswap lakes is 

 447 feet (136 m.), measured about 11 kilometres 

 north of Sicamous. The neighbouring Adams 

 lake, 70 kilometres long and 1,200 feet (366 m.) 

 deep, is a pure type of rock basin. Part of its 

 floor is almost at sea-level. 



From Sicamous the excursionists will obtain 

 their first view of the Belt of Interior Plateaus 

 here merging into the more rugged Columbia 

 range just traversed. The origin of the upland 

 facets of these plateaus is a problem not yet 

 completely solved. As a whole, however, they 

 represent a late Miocene or early Pliocene 

 land surface, dissected by streams revived 

 because of the general Cordilleran upwarp 

 during the Pliocene period. (See pp. 162-164.) 

 At and west of Sicamous station a partial 

 section of the Sicamous limestone (p. 124) may 

 be studied. It occurs in a fault-block showing 

 the exceptional Cordilleran N.W. — S E. strike, 



