They are described under different names in Siberia - the Altai Mountains in West Siberia, the Kuznetskiy Ala-tau and the Us and Oya Mountains in West Sayan, the Nizhne-Udinsk taiga or gold-mine district, several chains pierced by the Oka river, the Kitoi Alps in East Sayan, the mountains of the upper Lena and Kirenga, the Olekminsk gold-mine district, and the unnamed mountains which project north-east between the Lena and the Aldan.
In the region between Viluisk (on the Vilui) and Yeniseisk a broad belt of alpine tracts, reaching their greatest elevation in the northern Yeniseisk taiga (between the Upper Tunguzka and the Podkamennaya Tunguzka) and continued to the south-west in lower upheavals, separates the elevated plains from the lowlands which extend towards the Arctic Ocean.
This constitutes what is called in East Siberia the taiga: it consists of Alpine separate chains of mountains whose peaks rise 4800 to accompany the eastern edge of.
But even in these districts the botanist and the geographer can easily distinguish between the chern or thick forest of the Altai and the taiga of East Siberia.
The border-ridge character of the Sayans (Ergik-targak-taiga) is well established, and the same orographic character is confirmed by recent explorers with regard to the Sailughem range of the Altai.