THE LA S ANIMA S GLA CIER. A7S 



the top of the ridge had been glaciated, but it is certain the ice or 

 snow flowed in opposite directions from the col. On each side of 

 the pass, peaks of the Continental Divide rise above the col to a 

 height of iooo to 2000 feet. It is evident that the snow from these 

 peaks would flow or slide from each side down into the pass, and 

 maintain a supply of neve or ice right on top of the ridge in the 

 pass. The pass is about 11,800 feet high. It thus appears that 

 the snow fields reached nearly to the tops of the mountains, say 

 about 12,000 feet in the cirques and passes, while above this the 

 discharge was probably in large part by avalanches. 



Durango city is situated in about N. Lat. 37 ° 16', a few miles 

 north of the end of this glacier. It is to be carefully noted, in 

 the study of the climates of the glacial epoch, that a glacier 

 nearly seventy miles long reached so far south. Apparently the 

 most snowy part of Colorado now was also the most snowy then. 



During the retreat of this glacier it left numerous small 

 retreatal moraines, both in the main valley and in the tributary 

 valleys above Silverton. One of the most accessible is near the 

 junction of the two branches of Mineral creek, about three miles 

 northwest from Silverton. 



It is noticeable that the proportion of moraine stuff left by 

 this glacier is small as compared to the glacial sediments. No- 

 where have I yet found very noticeable ridge or terrace lateral 

 moraines. This is in part due to the steepness of the hills that 

 border the sides of the Animas valley. There is usually a 

 scattering of glaciated matter on these hill slopes, and where 

 they are less steep, or in lee of ridges projecting out into the 

 valley, local morainal sheets are sometimes found that have a 

 depth of twenty feet or more. Small terrace-like lateral 

 moraines extend for a mile or two north of the terminal 

 moraines of Animas City near Durango. Probably the snow 

 avalanches and flowing neve carried down debris and incor- 

 porated it with the glacier proper, so that there were no 

 large surface lateral moraines as in some of the valleys of the 

 Alps, or in the Arkansas and some other valleys of Colorado. 

 In other words, the debris of this glacier was largely englacial 

 and basal. George H. Stone. 



