A partly closed basin between ridges may supply a collecting ground for snows carried from neighboring slopes by the wind, and so may yield a broad névé, approaching in size a small ice cap, yet without developing definite ice streams except upon its border. Such a glacier is the Illecillewaet glacier of the Selkirks ([Fig. 415]).
Again in low latitudes the high and pointed volcanic peaks may push up beyond the snow line into the upper atmosphere, and so become snow-capped. Definite cirques do not develop well under these circumstances, and the loose materials of which such peaks are always composed are attacked in somewhat irregular fashion from the different sides. This is the case of Mount Rainier and similar peaks of the Cascade range of North America.
Summary of types of mountain glacier.—In tabular form the various types of mountain glacier may be arranged as follows:—
MOUNTAIN GLACIERS
Piedmont glacier. Mountain valleys entirely occupied and largely submerged, with overflow upon the foreland to form a common ice apron through coalescence of neighboring streams.
Expanded-foot glacier. Valley entirely occupied and an overflow upon the foreland sufficient to produce individual ice apron.
Dendritic glacier. Valley not completely occupied but with tributary ice streams ranged along the sides of the main stream, and with hanging glacierets separated near the glacier foot.
Radiating glacier. Glacier largely included in a cirque with subordinate glacierets converging below like the sticks in a lady’s fan.
Horseshoe glacier. Small glacier remnants hugging the cirque wall and having an incurving front.
Inherited-basin glacier. Of form dependent on a basin inherited and not shaped by the glacier itself.