Jeanette Ratclifffe in ‘Scilly’s Archaeological Heritage’ (Twelveheads Press, 1995) gives the following info. “Two prehistoric round houses and associated field wall. Though perhaps an Iron Age cliff castle because of its promontory location, none of the walls appear substantial enough to have formed a line of defence and an unenclosed settlement is more likely. Each hut consists of a levelled area enclosed by a circle of boulders set on edge. The field system comprises boulder walls, slightly lynchetted, standing a maximum of 0.6metres high”
‘The Earth Mysteries Guide to Ancient Sites on the Isles of Scilly’ (Meyn Mamvro, 1995, revised 1996 & 1999) adds little extra.