General agreement exists that the position of the base of the Cambrian (Precambrian-Cambrian boundary) should coincide with a biostratigraphic marker that can be widely traced and is linked to the evolution of the small shelly fauna. On the Siberian platform the presence of distinct facies during the Vendian-Cambrian interval has made biostratigraphic correlation based on palaeontological data highly contentious. A solution to this problem appears to exist with the recognition of an almost uninterrupted profile in the Aldan-Uchur watershed where key sections expose the eastern and transitional facial region. On this basis we present a general biostratigraphic scheme for the Vendian-Cambrian across the southern Siberian platform that connects separate facies. Further correlation with key sections in northern Siberia leads to the recognition of three biostratigraphic zones for the Vendian-Cambrian interval. These are: Anabarites trisulcatus Zone; Purella antiqua Zone; Aldanocyathus sunnaginicus Zone. The abundance of Chinese-type small shelly fossils in the region of the eastern facies suggest correlation of the A. sunnaginicus Zone with the Siphogonuchites-Paragloborilus Zone of China, and the P. antiqua Zone with the Circotheca-Anabarites-Protohertina Zone. In places, at the base of the Circotheca-Anabarites-Protohertzina Zone in China, analogies to the A. trisulcatus Zone can be identified. It is proposed that in Siberia the base of the A. sunnaginicus Zone (= base of Tommotian Stage) be taken as the base of the Cambrian. This would correspond with Marker B of the Meishucunian in China.
