41 



II. E. Gregory — A Geologic Reconnaissance 



rapids confined by closely spaced gravel walls. The two reces- 

 sional moraines looped on the valley floor are 20 feet and 6 

 feet high ; the moraine marking the farthest advance of the 

 ice during the last period of giaciation is a V-shaped wall of 

 debris 150 feet in height which stands at an elevation of about 

 13,100 feet (fig. 28). 



Patches of ground moraine in this area are found below 

 the terminal moraines, and valleys modified by ice extend to 

 the 12,500-foot contour line and at that level hang above 



Fig. 27. 



Fig. 27. Glaciated Valley near headwaters of Rio Chchiraura. 



deep-cut canyons trenching the mature slopes descending south- 

 ward to the Huatanay. Though somewhat difficult of access, 

 this locality is well worth a visit by those interested in 

 Pleistocene geology. 



Glacial Features South of the Cuzco Valley Axis. 



The glacial features on the southern margin of the Cuzco 

 Valley are less prominent and less well preserved than those 

 on the northern rim above described ; the southern ice cap was 

 thinner and shorter-lived. K"o lateral or terminal moraines 



