Except for the Derevyannye Hills, Pleistocene sediments blanket almost the entire surface of New Siberia Island. These deposits consist of layers of marine sediments overlain by terrestrial sediments. The lower marine sediments are composed of three superimposed beds of marine to brackish water clay containing fossil mollusks and capped with peat. The overlying terrestrial sediments consist of an ice complex composed of ice-rich wind-blown silt in which ice wedges have developed. This ice complex accumulated over tens of thousands of years during the Late Pleistocene, through the Last Glacial Maximum, until it stopped at about 10,000 BP. During this period of tens of thousands of years, the formation of ice complex buried and preserved in permafrost an enormous number of mammoth tusks and bones and the bones of other “megafauna”.