PALEOBIOGEOGRAPHY OF THE SAYAN-BAIKAL MOUNTAIN AREA IN THE CAMBRIAN
Two provinces are distinguished in the Sayan-Baikal mountain area from complexes of trilobites for the Cambrian system: Sibe-rian with sea shallow basins of the platform type and Altai-Sayan-Transbaikal, connected with island arcs, oceanic uplifts, prearc and backarc sea basins of the Paleoasian Ocean, the boundaries between which were almost constant during the whole Cambrian. The Most representative complexes of trilobites are abundant in the Toionsk time of the Lower Cambrian and Amgin time of the Middle Cambrian. Thus, all paleobiogeographic reconstructions were done for this time span. In the terminal Toionsk and Amgin time the sea paleobasins in the Sayan-Baikal mountain area had the association with epicontinental sea basin of the Siberian platform and Paleoasian ocean. The fauna in the Toionsk and Amgin time migrated from the north-east from the sea basin of the Siberian platform (in modern coordinates) to northern areas of the Sayan-Baikal Mountain area, and to the southern areas - from the Paleoasian Ocean.