THE WORK OF SNOW AND ICE. 



251 



(Fig. 226); if the depressions be narrow and deep, the lobes will be 

 relatively narrow and long. If the snow and ice rest on a surface con- 

 sisting chiefly of steep valleys and sharp ridges, as is common on m.oun- 

 tain slopes, the snow and ice are chiefly gathered in the valleys, and 

 take a hnear form. 



TYPES OF GLACIERS. 



These different forms give rise to different terms. The ice which 

 spreads with some approach to equality in all directions from a center 

 is a glacier, is indeed the type of the greatest glaciers, but is commonly 

 called an ice-cap. The same name is applied to any glacier in which 



Fig. 227. — Characteristic end of a North Greenland (Bryant) glacier. 



there is movement in all directions from the center, even though its 

 shape departs mdely from a circle. The glacier covering the larger 

 part of Greenland (Figc 222) is a good example of a large ice-cap, and the 

 glaciers on some of the flat -topped peninsular promontories of the same 

 island are good examples of small ones (Fig. 224). If ice-caps cover 

 a large part of a continent, as some of those of the past have done, 

 they are often called continental glaciers. _ 



