At the centre of the platform are two rectangular holes, connecting to passages beneath the structure which open out and emerge as 'windows' in its North wall
TREVALGA SX 09 SEWhim plat 100 metres to north west 1/224 of Manor House IIWhim plat. Circa early C19. Slate stone rubble. Built into side of steeply sloping bank above disused quarry and mine on sea edge. The semi-circular structure is a retaining wall with a flat platform on which the capstan was placed and 2 shafts with large openings on the lower side to accommodate the ropes used to haul the material from below.