On the Lena and the Vitim there are steamers, and a small railway connects the Bodoibo river port with the Olekma gold-washings.
This conformation is seen in the valley of the Us in West Sayan, in that of the upper Oka and Irkut in East Sayan, in the valley of the Barguzin, the upper Tsipa, the Muya and the Chara, at the foot of the Vitim plateau, as also, probably, in the Aldan.
- namely, in East Sayan about Lake Kosso-gol and in the valley of the Tunka (river Irkut), in the vicinity of Selenginsk, and widely distributed on the Vitim plateau (rivers Vitim and Tsipa).
Gold is found on the high plateau in the basin of the upper Vitim, on the lower plateau in the Nerchinsk district, and on the upper tributaries of the Amur (especially the Oldoi) and the Zeya, in the north-east continuation of the Nerchinsk Mountains.
Examples are the Ob and the Irtysh, the Yenisei and the Angara (itself a double river formed by the Angara and the Lower Tunguzka), the Lena and the Vitim, the Argun and the Shilka, while the Amur in its turn receives a tributary as large as itself - the Sungari.