Jeanette Ratclifffe in ‘Scilly’s Archaeological Heritage’ (Twelveheads Press, 1995) gives the following info. “On the north-western knoll is an entrance grave with a kerb of very large boulders and outcrop, and an off-centre chamber with walls but no capstones. Halfway along the ridge lies a second entrance grave with a kerb similar to the first and a chamber with its floor and walls of large boulders and natural rocks. No capstones remain. On the south-eastern knoll are an entrance grave and a cairn. The first has an oval mound with an incomplete stone kerb and a ruinous central chamber of boulders set on edge with two upright stones flanking its entrance but no capstones. The second is a circular cairn, partially kerbed with upright boulders and with an off-centre cist built against natural rock. Stone slabs form its other three sides, but no capstones survive”
Craig Weatherhill, in “Cornovia: Ancient Sites of Cornwall & Scilly” (Cornwall Books - 1985, revised 1997 & 2000) adds…”Each of the three summits of Cruther’s Hill carries barrows. The northern summit has an oval, kerbed mound with diameters of 12m and 8m. It is 0.9m high and incorporates natural outcrops. The chamber, in an off-centre position near the south-western end of the mound, appears rather cist-like despite its length of 3.8m. It is 0.7m wide, with its western end covered by one surviving capstone. The tomb on the central summit is an unmistakable entrance grave, 8m in diameter and 1.8m high. It has a massive kerb, broken on the north-east by the entrance to a roofless chamber 4.7m long, 1.2 long (sic), and 1.0m deep. The southern summit bears the remains of two conjoined barrows. The northernmost, 6.5m across, incorporates natural rock. In the centre are the remains of what may have been an entrance grave, but its original plan and orientation are impossible to ascertain from surface appearance. The southern mound is 4.5m in diameter and 0.8m high and retains much of its kerb. There is a large natural boulder within the kerb, but no trace remains of any chamber or cist that the barrow may have held. All the barrows are likely to be of late Neolithic or Early Bronze Age date.”
Cornovia also has two of Weatherhill’s classic sexy diagrams. Note – the photo in Cornovia is actually of Bant’s Carn (from the opposite page).