Drilling at Site 281 on the South Tasman Rise recovered fragments of carbonaceous quartz-muscovite-chlorite semischist. The schist was developed by very low-grade regional metamorphism (greenschist facies) of a sedimentary rock that was poorly sorted and quartz rich. An average of two whole-rock potassium-argon ages of the semischist is 306 + or - 10 m.y. Analysis of the drilling record strongly suggests that semischist bedrock was reached at 159.5 m and was penetrated to a depth of 169.0 m. The results establish the continental nature of the crust underlying the South Tasman Rise. The semischist at Site 281 may correlate with the Cambrian-Precambrian Robertson Bay Group of Northern Victoria Land, Antarctica. A reconstruction of the Australo-Antarctic part of Gondwanaland that places the South Tasman Rise near Victoria Land leads to significant overlap in the Ross Sea area. Following the suggestion of Hayes and Ringis (1973), this overlap can be eliminated by restoring approximately 400 km of left lateral movement between east and west Antarctica.