414 I' H. OGILVIE 



The abnormalities in the vicinity of Banff village appear to be 

 due to glacial agencies only. Forty-mile Creek talces its abrupt 

 westward bend at the point where its old valley is filled by drift. 

 The Bow takes its southward turn around Tunnel Mountain for 

 the same reason, namely, damming of its old valley by drift, its 

 present rapids and fall being postglacial. South of Tunnel Moun- 

 tain the Bow leaves its gorge and turns into the preglacial valley of 

 the Spray (Fig. 4). The Spray itself has been pushed out of its 

 valley at this point by talus from Mount Rundle. 



I. H. Ogilvie. 



Geological Department, 

 Columbia University. 



