Chalk

This is a short overview — for the full history, value over time and notable mines, see Chalk →

Occurs in: Sedimentary Beds and Seams →

A soft, fine-grained white limestone formed from compacted marine microfossils, quarried both for a locally hard building-stone variety known as clunch and, far more commonly, dug and spread on fields as marl to improve heavy clay soils.

Mines

Mine	Region	Worked
Hangman's Wood Deneholes	Essex	Medieval or post-medieval (exact date disputed)–Largely disused by the 19th century; access restricted since
Totternhoe Stone Mines	Bedfordshire	Worked from the Roman period; underground galleries from the medieval period–Underground working ended around 1925; small-scale surface extraction continues