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End moraine is a ridgelike accumulation of till (see definition of ice-laid material) built along any part of the margin of a glacier. Lateral moraine is an end moraine built at the lateral edge of a glacier occupying a valley. The cross section is usually a convex triangle rather than a pronounced triangle of the esker. The till material is derived mainly from the valley sides. Lateral moraine is similar to a kame terrace, but is distinguished by the lack of sorting and stratification and no evidence of water action during deposition. In areas where two separate ice lobes or valley glaciers meet, the lateral moraine from the flows will join to form an interlobate or medial moraine.
The composition of the till can vary from 99% clay to 99% boulders. The material is usually unsorted and unstratified. In valley glaciation, the frost action causes weathering of the unglaciated slopes and provides a source of debris for the lateral moraines.
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