Early C19. Set upon granite sea wall a low brick fortification having 2 splayed gun embrasurers lined with sandstone and topped with thick, granite blocks. Immediately behing these, at either side, a circular platform stepped and sloped down from fortifying wall and up from road behind. Sandstone on brick foundation, steps and floor of granite. In centre round block with pin to form turntable; and metal rail around outer segment. These supported late C18 or early C19 naval pieces, on wood carriage platforms swivelling through an angle of about 3000. One of the guns is now in Plumstead Library museum. 2 posts made of filled gun barrels well sunk into the ground, with rings for chains embedded in tops. Probably used for help in swivelling guns.