Fig. 1. Stonehenge in context.

(A) Distribution of silcrete boulders across southern Britain, including sarsens and conglomeratic variants known as puddingstone [data from (16, 22, 28, 46, 47)]. (B) Sampling sites and topography in the Stonehenge-Avebury area [areas in pale gray at 100 to 175 m above sea level (asl), and those in dark gray at 175 to 270 m asl], along with proposed transportation routes for the sarsen stones. (C) Plan of Stonehenge showing the area of the monument enclosed by earthworks plus numbered peripheral sarsen stones. (D) Detail of the main Stonehenge monument showing the remaining bluestones and numbered sarsen stones.