The chalk comes in three layers: the upper layer, about 500 feet thick, is a pure white limestone bedded and jointed with localised masses of flint (ideal for cement); the middle layer, about 170 feet thick, is a compact white chalk occasionally hard enough for building; the lower layer, about 170 feet thick, is a greyish marly chalk.
The chalk is composed of three distinct layers: an upper stratum, approximately 500 feet in thickness, consisting entirely of white limestone with embedded flint deposits (suitable for binding); a middle section, roughly 170 feet thick, comprising compact white chalk suitable for construction; a lower layer, about 170 feet thick, characterized by greyish marly chalk.