lateral moraine

Linear ridge of rocky debris deposited near the edge of a glacier. Much of the debris is material that has fallen from the valley side onto the glacier's edge, having been weathered by freeze-thaw (the alternate freezing and thawing of ice in cracks); it will, therefore, tend to be angular in nature. Where two glaciers merge, two lateral moraines may join together to form a medial moraine running along the centre of the merged glacier.