At http://www.west-penwith.org.uk/just4.htm there appear to be two seperate references , one to a vau at Pendeen and the other a fogou at Boscaswell . Archsearch lists two fogous at Boscaswell with the grid reference SW3734 . Again these are seperate records ; EHNMR-625830 excavated in 1864 and EHNMR-625544 in 1954/5 . No prehistoric or Roman cairn .