The big stones of the chambers and the smaller ones making up the core of the mound are from the Marlborough Downs. But the (ton weight of) drystone walling of the facade is made from oolitic limestone and calcareous grit – which must have been brought from Frome and Calne, 25 and 7 miles away, respectively.
(in Aubrey Burl’s ‘Prehistoric Avebury’)