Elsewhere in the country, chalk used as building stone is known as clunch, but around here I believe it's known as 'chalk-stone'. In any case, this cottage appears to be built of neatly squared-off blocks of chalk. The roof seems to be slabs of locally-quarried sedimentary rock, similar to the 'Collyweston slates' used in Northamptonshire, Rutland, and south Lincolnshire.
Uploaded to Geograph by Stefan Czapski on 6 August 2016
Photo © Stefan Czapski, 6 August 2016. Licensed for reuse under this Creative Commons licence