But the great lakes which covered the country during the Lacustrine period have disappeared, leaving behind them immense marshes like those of the Pripet and in the N.E.
A third depression, traversed by the Pripet and the middle Dnieper, extends to the W.
Dvina, and the Pripet, both very important for navigation - as well as several smaller tributaries on which rafts are floated; on the left the Sozh, the Desna, one of the most important rivers of Russia, navigated by steamers as far as Bryansk, the Sula, the Psiol and the Vorskla.
The Dnieper and Bug canal in Grodno connects the Mukhavets, a tributary of the Bug, with the Pina in the basin of the Pripet, that is, the Dnieper with the Vistula.
The lime appears in groves only in the east (Memel, Pripet, Lublin).