The original walls were clunch and were pilfered by a bastard son of Henry the Eighth to build Berkhamsted Place.
As it's a large square Norman keep and it's still in good condition, clunch can be a very hard stone and weather well.
Another small area of clunch is noted where a garden path crosses the western end of a low bank to the east, possibly indicating a wall alignment, although no masonry evidence is otherwise noted.
There is a great variety of materials in the older buildings but a particular characteristic is the use of Chilmark Stone and a chequered pattern of clunch and napped flint.
There are useful resources within the parish: flints for tool making and building, a band of hard chalk called clunch also for building, and areas of woodland and gravel.
Origin
Early 19th century: perhaps from dialect clunch 'lumpy, thickset'.