AGGLESTONE, a large isolated block of ferruginous sandstone, about a mile NW of Studland village, in the parish of Studland, Dorset. It crowns a hillock nearly a mile from the shore; measures 37 feet in length, 19 feet in breadth, and 15 feet in height; and is regarded by some persons as merely a boulder,-by others as a Druidical monument. The common people allege it to have been thrown by the Devil, from the Isle of Wight, to demolish Corfe Castle; and call it the Devils Nightcap.

(John Marius Wilson, Imperial Gazetteer of England and Wales (1870-72))