I thought I’d dig out what information the excellent ‘Hampshire Treasures’ resource gives on this stone. They have it under natural features – “Sarsen Stone No. 47A – County boundary – ancient track junction. One example of sandstone boulders dating from prehistoric times, which were often used in olden days for religious purposes and also served as boundary marks in ancient fields. Ref: 1. The Kennet Valley Sarsen Industry, Wiltshire Archaeological Magazine 63, 1968, pp.83-93. Ref: 2. P.H.F.C., Vol. 2, Nos. 9 and 10, p.116.”