Prehistoric India to 1000 B.C. c9.5

c9.5

Throughout the Pleistocene there occurred certain enormous rhythmic climatic changes, spread over many thousand years but constituting alternate phases of comparative heat and cold in the northern regions of the Old World, and probably corresponding phases of wet or dry climate farther south. The cold phases, during which the limit of what is now the North Polar ice-sheet spread south in Europe to form a continuous ice mass to the River Thames in England and in the Himalayas of North India reached the foothills, are the familiar Ice Ages or glacial periods, separated by interglacial phases, both of varying periods of duration. Four main glacial periods have been recognized, separated by three interglacials, and the study of Palaeolithic man is closely linked to these great changes, which were directly responsible for the limits of land available for human occupation or settlement, and for the climate beyond the fringes of the zone of permanent, uninhabitable ice.