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In the valley glaciers, the rock fragments falling upon the ice from the valley sides, or sliding down in avalanches, accumulate upon the side of the ice, and as the glacier moves a long, such accumulations are strung out in lines of drift along the margin. This constitutes a lateral moraine.

Lateral Moraine

In the valley glaciers, the rock fragments falling upon the ice from the valley sides, or sliding down…

Where two glacial streams unite, their adjoining lateral moraines become confluent and are continued as a medial moraine.

Medial Moraine

Where two glacial streams unite, their adjoining lateral moraines become confluent and are continued…