Further Exploration of Centre Valley 



a study of their mode of formation until we should be 

 able to penetrate farther in the direction of the great 

 snowfields which fed the glacier. 



Several tributary valleys joined the main one on both 

 flanks of the glacier. Two which we visited on the east 

 side discharged their waters into the area occupied by the 

 lateral moraines, forming a small lake whose waters 

 eventually escaped through the narrow gaps between the 

 moraine-ridges. 



A third valley 

 higher up on the same 

 bank we found to con- 

 tain a lake, the waters 

 of which were held up 

 by the ice of the 

 glacier, which here oc- 

 cupied the main valley 

 from side to side. The 

 overflow of this lake 

 escaped by a short 

 channel cut through 

 the solid rock of the 



spur, and was eventU- FIG. 32. Map of glacier lake. , Overflow 

 1-1 i channel. 



ally discharged into 



the moraine tract. This action was precisely similar to 

 what we believed to have taken place in the case of the 

 dry channels described on p. 260. 



The edge of the ice curved into the lake in the 

 manner indicated in Fig. 32, and the surface of the water 

 was dotted over with small icebergs which had broken 

 away from it. 



Such lakes are well known in many parts of the 



267 



