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Geological Character

The range of the Chiltern hills consists of chalk, which occupies the south-eastern part of the county, and is skirted along its NW boundary by a belt of indurated chalk-marl, much covered by the debris of the chalk hills. This chalk-marl is known in the county by the name of clunch, and is extensively quarried at Toternhoe near Dunstable. It affords, by burning, a good is lime. The chalk-marl is blended with a blue marl, which may perhaps be identical with the weald-clay of Kent, Surrey and Sussex, or with what has been denominated the Folkestone clay. Iron-sand, the lowest of the formations which intervene between the chalk and the oolites, stretches across the county in the same direction as the other formations, viz., from SW to NE. Beds of fullers' earth, which occur in it, have been extensively worked, and in Fuller’s time this mineral was known by the name of Woburne earth. The same formation contains also a considerable quantity of fossil wood. This iron-sand rises into a well defined range of hills.

To the iron-sand succeeds a tenacious adhesive clay of a dark blue colour, becoming brown on exposure, and known by the name of Oxford clay. This stratum forms the vale of Bedford, and affords a strong clay soil, occupied chiefly in pasturage. It supplies several brick-kilns in the immediate vicinity of the town, in one of which part of a new species of Plesiosaurus was discovered in 1833. Many vertebrae of fossil Sauri have been found at Nemenham Mill, near Goldington : and an entire Plesiosaurus, of large dimensions, was discovered in 1833, in a brick-field about two miles north-west of Bedford, near the Ouse. The appearance of coal gave rise to some attempts to find that mineral at Elstow near Bedford, which ended in disappointment. In the NW part of the county, the Cornbrash limestone appears, and is quarried in several places. The Oxford clay and the Cornbrash limestone are parts of the oolitic series.

Several springs in the county are impregnated wtth different minerals, but none of them are of any note. Drayton in his "Poly-Olbion" (22nd song), as quoted by Fuller, speaks of a brook at Apsley Guise, near Woburn, the earth on the banks of which had a petrifying quality : but this account has been ascertained to be incorrect. Late compilers, borrowing probably from Drayton and Fuller, speak of a petrifying spring near Woburn.

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