More recently remains both of the upper and lower jaw have been met with in the Hastings Beds in Tilgate Forest. Their size was somewhat greater than had been anticipated, and even allowing that the tail was short, which Professor Owen infers from the short bodies of the caudal vertebrae, Dr. Mantell estimates the probable length of some of these saurians at between 30 and 40 feet. The largest femur yet found measures 4 feet 8 inches in length, the circumference of the shaft being 25 inches, and round the condyles 42 inches. [2 Illustrations: Teeth of Iguanodon. Fig. 230. Partially worn tooth of a young animal. (Mantell.) Fig. 231. Crown of tooth in adult, worn down. (Mantell.)] Occasionally bands of limestone, called Sussex Marble, occur in the Weald Clay, almost entirely composed of a species of _Paludina_, closely resembling the common _P. vivipara_ of English rivers. [Illustration: Fig. 232. _Cypris spinigera_, Fitton.] [Illustration: Fig. 233. _Cypris Valdensis_, Fitton. (_C. faba_, Min. Con. 485.)] [Illustration: Fig. 234. _Cypris tuberculata_, Fitton.] [Illustration: Fig. 235. Sample with lamination.] Shells of the _Cypris_, an animal belonging to the Crustacea, and before mentioned (p. 31.) as abounding in lakes and ponds, are also plentifully scattered through the clays of the Wealden, sometimes producing, like the plates of mica, a thin lamination (see fig. 235.). Similar cypriferous marls are found in the lacustrine tertiary beds of Auvergne (see above, p. 183.). _Hastings Sands._ This middle division of the Wealden consists of sand, calciferous grit, clay, and shale; the argillaceous strata, notwithstanding the name, being nearly in the same proportion as the arenaceous. The calcareous sandstone and grit of Tilgate Forest, near Cuckfield, in which the remains of the Iguanodon and Hyleosaurus were first found, constitute an upper member of this formation. The white "sand-rock" of the Hastings cliffs, about 100 feet thick, is one of the lower members of the same. The reptiles, which are very abundant in it, consist partly of saurians, already referred by Owen and Mantell to eight genera, among which, besides those already enumerated, we find the Megalosaurus and Plesiosaurus. The Pterodactyl, also a flying reptile, is met with in the same strata, and many remains of Testudinata of the genera _Trionyx_ and _Emys_, now confined to tropical regions. [Illustration: Fig. 236. _Lepidotus Mantelli_, Agass. Wealden. _a._ palate and teeth. _b._ side view of teeth. _c._ scale.]