When a glacier remains practically stationary for some time, more or less material which it carries is piled up at its lower end to form a terminal moraine. Repeated pauses during general glacier retreat permit the accumulations of so-called recessional moraines. A wonderful display of recessional moraines occurs from the Great Lakes south, where they are festooned one within another and remain almost exactly as they were formed during pauses in retreat of great lobes of ice during the closing stages of the Ice Age. A great terminal moraine marks the southernmost limit of the ice sheet during the Ice Age, a very fine illustration being the ridge of low irregular hills extending the whole length of Long Island. Some of the material in that morainic ridge was transported by the ice from northern New England. Considerable rock débris is transported within the ice, and such "englacial" material in part results from rock débris which falls on the surface in the catchment basin and becomes buried under new snowfalls which change to ice, and in part from material which falls into the crevasses in the glacier farther down the valley. Marked objects thrown into the catchment basin have, after many years, emerged at or near the end of the glacier; thus the rate of motion can be very accurately told. A very remarkable case of transportation through the body of a glacier is the following: In 1820, three men were buried under an avalanche in the catchment basin of the Bossons Glacier in the Alps. Forty-one years later several parts of the bodies, including the three heads together with some pieces of clothing, emerged at the foot of the glacier after traveling most of its length at the rate of eight inches per day. The heads were so perfectly preserved after their remarkable journey in cold storage that they were clearly recognized by former friends! Where a valley floor slopes downward away from the end of a glacier, waters emerging from the ice, heavily loaded with rock débris, cause more or less deposition of the débris on the valley floor often for miles beyond the ice front. Such a deposit is called a "valley train." When the ice front pauses for a considerable time upon a rather flat surface, the débris-laden waters emerging from the ice develop an "outwash plain" by deposition of sediment rather uniformly over the flat surface. A very fine example is the plain which constitutes most of the southern half of Long Island just beyond the southern limit of the great terminal moraine ridge.