Extended Data Figure 1: Distribution of Acheulian, Middle Palaeolithic and Late Palaeolithic sites currently under investigation in the immediate vicinity of ATM, north-eastern Tamil Nadu.

White circles: known prehistoric sites. Note their presence only on interfluves or near smaller streams, and never on the riverbank of the largest local river (Kortallaiyar). Black squares: selected villages and towns. Red tone: vegetation (intensity increases with moisture content). Grey-to-green: dry crops and bare soil. Laterite caprock occurs in the north and forms the high ground on the divide between the drainages of the Kortallaiyar and Arani rivers. Note that topographic gradients in the landscape can be inferred from the strike of the runoff-harvesting dams: some village reservoirs contain water, whereas others—which form dark crescentic patches in the image—are mostly dry. The land slopes perpendicular to dam orientation. False-colour IKONOS image, 1 m ground resolution. Reprinted from ref. 26, with permission from Elsevier.