PRK-CAMBRIAX ROCKS OF THE BOW VAI.LEV — WALCOTT 425 



and beautiful one. To the north and far below lies the broad valley 

 of the Bow, which stretches to the southeast toward Banff and 

 northwest to the beautiful Hector Lake. Rising above the valley on 

 the northeast rugged mountains extend in massive ridges and high 

 peaks from Mount Hector to Mount Richardson, and southeastward 

 to the great wall of Castle Mountain and the serrated Sawback 

 Range. Farther to the southeast are the high points of the Bourgeau 

 Range west of Banfif, and beginning with Mount Temple and arch- 

 ing to the south and southwest there is a superb panorama of high 

 mountains, glaciers, and crested walls, such as is rarely seen in any 

 land. As a study in glaciation and topographic forms it is unex- 

 celled, and is well worth a journey across the continent to see." 



Panoramic photographs taken from high on the mountains on both 

 sides of the valley show that the valley has been excavated on the 

 northeast slope of a broad, broken anticlinal arch. The general 

 average height of the peaks and ridges as they are massed against 

 the horizon indicates a base-leveling of the region prior to the period 

 of uplift and erosion that has developed the present topography. 



The topographic forms resulting from the erosion of the Cam- 

 brian rocks are well shown on all the higher mountains adjoining 

 the valley — Mounts Temple, Aberdeen, Victoria, and Hector. Fort 

 (fig. 2, pi. 45) and Castle mountains are capped by high, precipitous 

 cliflfs of limestone underlain by alternating slopes of shale and bro- 

 ken clififs of sandstone for 2,000 feet or more down to the low cliff 

 formed by the Fairview^ sandstone or its basal conglomerate. Below. 

 ihis cliff the pre-Cambrian shales and sandstones form smooth slopes 

 and irregular, rounded hills and ridges with bands of gray, purple, 

 and greenish shales. These are well shown southeast of Mount 

 Hector and the ridges south of Mount Richardson and Fort ]\Ioun- 

 tain (fig. 2, pi. 46). The contrast of topographic form between 

 the Cambrian and pre-Cambrian rocks is finely illustrated by Fort 

 Mountain (fig. 2, pi. 45) and the area just south of it (fig. 2, pi. 46), 

 and it first led me to suspect the presence of pre-Cambrian rocks in 

 this area. 



BASAL CAMBRIAN ROCKS 



The conglomerate at the base of the Fairview formation is massive 

 bedded and usually formed of small quartz pebbles in a coarse sand- 

 stone matrix. At Fort Mountain it is over 300 feet thick and ex- 

 tends northw^est and southeast for a long distance. The white quartz 

 pebbles here vary from 2 mm. to 10 cm. in diameter (average 10-15 

 mm.), and are mixed near the base of the conglomerate with rounded 



