This unusually shaped natural flint (PRM 1884.140.1308) is covered in a black deposit. It was excavated in 1868 from a pit located between St. Peter's and Reading Street on the Isle of Thanet.
Pitt-Rivers, A. H. L. F. 1882. Excavations at Caesar's Camp near Folkestone, conducted in June and July 1878. Archaeologia 47(2): 429-465.