climates of Saalian ice-wedges and other permafrost. In some locations, the Eemian lake deposits are thicker and laterally continuous enough to form a complete blanket overlying older sediments. The Eemian sediments contain fossils indicative of an interglacial environment. At many localities along the sea cliffs, typically over 10 meters of Early Weichselian lacustrine and loess-like floodplain deposits overlie the Eemian and pre-Eemian sediments. These sediments consist of fine-grained, well-sorted sands with rare grass and sedge pollen. They contain ice wedge polygon systems that formed during the Early Weichselian stadial, about 100,000 to 50,000 years ago, as the result of extremely cold and dry conditions. Typically, 15 to 20 meters of Middle Weichselian ice complex deposits, which consist largely of aeolian sediments that accumulated 50,000 to 28,000 years ago, overlie the Early Weichselian sediments. These sediments contain pollen typical of the mammoth tundra-steppe environments and large ice wedge polygon systems. These sediments accumulated within a swampy, poorly drained habitat, which existed under an extremely cold continental climate. A zone of peaty deposits within this ice complex accumulated during a Middle Weichselian interstadial about 40,000 to 30,000 years ago. The Middle Weichselian deposits underlie the upland surfaces of this part of Bolshoy Lyakhovsky Island. Within the southern sea cliffs of Bolshoy Lyakhovsky Island, Late Weichselian sediments of the Last Glacial Maximum have not been found. The Ice Complex deposits associated with this period of time appear have been eroded and covered by Holocene deposits. Where thermokarst depressions have formed by melting of the permafrost, they are filled by Holocene solifluction and lake sediments. These depressions formed as the result of the thawing of ice wedges and other permafrost during the Late Pleistocene-Holocene transition about 12,000 to 10,000 years ago. Lacustrine sediments filling these depressions contain a record of the Allerød warming, Younger Dryas cooling, and other climatic events. Holocene fluvial and solifluction deposits underlie valleys of streams cut into underlying Pleistocene sediments. Solifluction deposits, which were created by melting of the underlying permafrost, veneer the surface of the uplands. New ice wedge polygon systems later formed in these sediments during the Late Holocene as result of pronounced climatic cooling, which only recently has reversed in the last couple of hundred years. Because of the formation of permafrost in these sediments and their depositional environments, prehistoric bone, shell, and plant material are well preserved and abundant. As noted above, later researchers found that