a depression in the ocean floor off Cape Agulhas, on the boundary of the Atlantic and Indian oceans. On the south the Agulhas Basin is bordered by the African-Antarctic Ridge; on the north, by the continental slope of South Africa. In the northern half the floor is flat (depths of 5,000–5,200 m), and in the southern half it is rugged (depths of 4,000–5,000 m and in places to 6,000 m). The waters over Agulhas Rise, which lies in the northeast portion of the basin, reach a depth of 2,500 m; some peaks rise to a height of 2,000 m. The bottom is red abyssal clay, with foraminiferous muds in the north and the Agulhas Rise.