Eskers are narrow, winding ridges of stratified sand and gravel whose general course lies parallel with the movement of the glacier. These ridges, though evidently laid by running water, do not follow lines of continuous descent, but may be found to cross river valleys and ascend their sides. Hence the streams by which eskers were laid did not flow unconfined upon the surface of the ground. We may infer that eskers were deposited in the tunnels and ice-walled gorges of glacial streams before they issued from the ice front.
Fig. 357. Kames, New York
Kames are sand and gravel knolls, associated for the most part with terminal moraines, and heaped by glacial waters along the margin of the ice.
Fig. 358. Diagram Illustrating the Formation of Kame Terraces
i, glacier ice; t, t, terraces
Kame terraces are hummocky embankments of stratified drift sometimes found in rugged regions along the sides of valleys. In these valleys long tongues of glacier ice lay slowly melting. Glacial waters took their way between the edges of the glaciers and the hillside, and here deposited sand and gravel in rude terraces.