Polotsk Lowland

a lowland in the northern Byelorussian SSR, in Vitebsk Oblast. It is located in the basin of the upper Zapadnaia Dvina and its tributaries. Its elevations range from 150 to 160 m. The surface is flat and slopes to the northwest. There are morainal hills, ridges, and dunes, and the river valleys are cut by ravines. The lowland is composed of lacustrine clays and sands and of ground moraine. Outcrops of Devonian dolomites and limestone are encountered, and there are mineral springs. Although considerably cultivated, the Polotsk Lowland is still thickly forested, chiefly with pine forests mixed with aspen, alder, spruce, and oak.