7MacDonogh, Steve. The Dingle Peninsula. Dingle, Co. Kerry, Ireland: Brandon, 2000. 60-62.
The author states that Lewis, in his Topographical Dictionary (1837), claims that the fortification on the eastern cliff was built specifically for the bombardment of the castle.
Ashe (ibid) notes that the cannons on the cliff were augmented by those of British naval forces in the bay.