The chief first-class fortresses of Russia are Warsaw and Novogeorgievsk in Poland, and Brest-Litovsk and Kovno in Lithuania.
The same is true of the plateaus of Livonia, " Wendish Switzerland," and the government of Kovno, which do not exceed moo ft.
Source, and steamers ply as far as Kovno; it is connected by the Oginsky canal with the Dnieper.
Isolated black-earth islands, though less fertile, occur also in Courland and Kovno, in the OkaVolga-Kama depression, on the slopes of the Urals, and in a few patches in the N.
In Kovno, Vilna, Mogilev, Grodno, Volhynia, Podolia, Minsk, Vitebsk, Kiev, Bessarabia and Kherson, they constitute, on the average, 12 to 172% of the population, while in the cities and towns of these governments they reach 30 to 59% of the population.