By 1560 all the Finnic and Tatar tribes between the Oka and the Kama had become Russian subjects.
The double river-systems of the Volga and Kama, the Ob and Irtysh, the Angara and Yenisei, the Lena and Vitim on the Arctic slope, and the Amur and Sungari on the Pacific slope, are instances.
The White Sea has also been brought into connexion with the central Volga basin while the sister-river of the Volga - the Kama - became the main artery of communication with Siberia.
Those of the later Lacustrine period, on the contrary, are so numerous that there is scarcely one lacustrine basin in the regions of the Oka, the Kama, the Dnieper, not to speak of the lake-region itself, and even the White Sea coasts, where remains of Neolithic man have not been discovered.
The Ural industry is the older, and is still conducted on primitive methods, wood being largely used for fuel, and the ore and metals being transported by water down the Kama and other rivers.