Remains of the largest known kinds of Pterodactyle have been discovered more recently in chalk-pits, at Burham, in Kent. The skull of one of these species—the Pterodactylus Cuvieri—was about twenty inches in length, and the animal was upborne on an expanse of wing of probably not less than eighteen feet from tip to tip. The restored specimen of this species is numbered 3.
A second very large kind of Pterodactyle—the Pterodactylus compressirostris, or Thin-beaked Pterodactyle—had a head from fourteen to sixteen inches in length, and an expanse of wing, from tip to tip, of fifteen feet. The remains of this species have also been found in the chalk of Kent. From the same formation and locality a third large kind of Pterodactyle, although inferior in size to the two foregoing, has been discovered, called the Pterodactylus conirostris, and also—until the foregoing larger kinds were discovered—Pterodactylus giganteus. The long, sharp, conical teeth in the jaws of the Pterodactyles indicate them to have preyed upon other living animals; their eyes were large, as if to enable them to fly by night. From their wings projected fingers, terminated by long curved claws, and forming a powerful paw, wherewith the animal was enabled to creep and climb, or suspend itself from trees. It is probable, also, that the Pterodactyles had the power of swimming; some kinds, e.g., the Pterodactylus Gemmingi, had a long and stiff tail. “Thus,” writes Dr. Buckland, “like Milton’s Fiend, all qualified for all services and all elements, the creature was a fit companion for the kindred reptiles that swarmed in the seas, or crawled on the shores of a turbulent planet.
‘The Fiend,
O’er bog, or steep, through strait, rough, dense, or rare,
With head, hands, wings, or feet, pursues his way,
And swims, or sinks, or wades, or creeps, or flies.’
Paradise Lost, Book II.”
THE WEALDEN.
The Wealden is a mass of petrified clay, sand, and sandstone, deposited from the fresh or brackish water of probably some great estuary, and extending over parts of the counties of Kent, Surrey, and Sussex. This fresh-water formation derives its name from the “Weald” or “Wold” of Kent, where it was first geologically studied, and where it is exposed by the removal of the chalk, which covers or overlies it, in other parts of the South of England.
The Wealden is divided into three groups of strata, which succeed each other in the following descending order:—
1st. Weald Clay, sometimes including thin beds of sand and shelly limestone, forming beds of from 140 to 280 feet in depth or vertical thickness.
2nd. Hastings Sand, in which occur some clays and calcareous grits, forming beds of from 400 to 500 feet in depth.
3rd. Purbeck Beds, so called from being exposed chiefly in the Isle of Purbeck, off the coast of Dorsetshire, where it forms the quarries of the limestone for which Purbeck is famous: the beds of limestones and marls are from 150 to 200 feet in depth.