This is the site of a post-medieval gun battery, including the earthworks of a prominent gun emplacement. The First Edition 1:2500 Ordnance Survey mapping of 1868 shows an almost circular earthwork ranging from approximately 20 to 30m in diameter: the centre of the mound is sunken to provide a faintly polygonal gun emplacement, though there is no indication to suggest how many pieces might have been mounted.  


In 1955 an OS fieldworker described a slight bank 2m wide and 0.2m high surrounding the hollow without an obvious break to provide an entrance. Today the top of the mound is somewhat mutilated, with signs that the bank is weakest or most eroded on the south-southwestern side, and it is difficult to be sure if the Ordnance Survey illustration was wholly accurate or somewhat conventionalised.


The battery was built in 1648 by James Stanley, 7th earl of Derby and Lord of Man, on the advice of Sir Arthur Ashton (or Aston).  The earl was a staunch Royalist during the Civil War who went to considerable trouble to fortify the Isle of Man against Parliamentary attack. Ashton was an acknowledged artillery specialist who was later killed in the Parliamentary massacre of the defenders of Drogheda in 1649. The battery was positioned to overlook or command Peel Castle, and supposedly designed to prevent its takeover or occupation by rebel forces; it is too high above sea-level to have functioned conventionally or effectively for coastal defence against shipping. The site is sometimes referred to as Cronk y Caitnys, which translated from Manx Gaelic means 'hill of the common'.