Cadbury Castle, Somerset: the early medieval archaeology - Leslie Alcock, Sylvia J. Stevenson, Chris Musson - Google Books

https://books.google.de/books?hl=de&id=h4pnAAAAMAAJ&dq=flatfish+chamfered

Cadbury Castle, Somerset, is an impressively large hillfort, originally built in the Celtic Iron Age and briefly overrun by the Roman army in the first century AD. It has the longest record of occupation of any hillfort in Britain, for its defences were…