Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/256

 radiated pyrites, globular or kidney-form. It is considerably harder than the common chalk and its colour is usually some shade of grey. It is well known in this county under the name of clunch, and is the material from which the best lime is burnt. Some of the beds are hard enough to serve the purpose of building stone, and are quarried and shaped in blocks for that purpose. It also endures the fire well, and, like the Ryegate stone in London, is much esteemed for the backs of grates and other similar applications.

This stone is dug in the greatest quantities at Reach, a small hamlet in the parish of Burwell, situated on the skirts of the fen country precisely where the Devil's ditch terminates in that direction. The excavations at this place are immense.

Clunch, when burnt, affords a lime in such universal esteem that the crude material is sent from hence for that purpose as far as Peterborough and other distant places, within reach of the water carriage of that level district.

The bedding of a chalk hill is difficult to ascertain, on account of the great number and irregularity of the rifts and joints intersecting the stone in all directions. By careful observations however, made in different places, I am enabled to state that the general direction of the. beds is from the N.E. to the S.W. and that they have a gentle inclination to the S.E. Their direction consequently coincides with the line that I have mentioned above, as dividing the upper from the lower chalk.

In one of the pits at Reach a bed of clunch occurs, which differs from the ordinary sort and presents some remarkable appearances; the mass itself is much harder, and stuck full of concretions of a yellow indurated marl: outwardly they are of a green colour arising from the oxide of iron: they are in general kidney-shaped