[Plate XXIII.]
The Gault hitherto has yielded but scanty remains of animals referable to the Reptilia and to the Palæosauria; so that more than ordinary interest attaches to the discovery, in a comparatively perfect condition, of remains belonging to a genus found hitherto only in New Zealand, which may be regarded as distinctive of the deposit. The remains of this Plesiosaurian were first found, rolled and abraded, at the foot of the cliffs; much of the caudal region of the animal may therefore have disappeared by attrition, and by the gradual decay of the bones as exposed in the clay, which has partly invested them with selenite. These bones were sent by Mr. Griffith, the well-known Folkestone fossil-collector, to J. S. Gardner, Esq., F.G.S., who traced them to their place in the Cliff, about 15 or 16 feet from the base of the Gault, and undertook excavations which have resulted in the discovery of a tooth, of the vertebrae of the neck and back, the principal bones of the limbs, and portions of the pectoral arch. The head, the tail, the pelvic bones, and the smaller bones of the limbs, together with most of the ribs, have not been found; and it is possible that some of these parts of the skeleton may have become severed before the specimen was covered up in the deposit, Mr. Gardner having used all possible efforts to discover the missing remains. The neural arches appear to have been united to the centrums; and several vertebras were extracted by Mr. Gardner with the neural arches entire; but, from the brittle condition of the fossils, it was not found easy to preserve the specimens in an unbroken condition.
There is necessarily some uncertainty about the exact generic determination of this Plesiosaurian; for the bones which might have cleared away all doubt are not well preserved. It is probable that it may be referable to Mauisaurus, which was about as large; and I have referred it to that genus, partly because it is a Cretaceous fossil, and partly because in vertebral characters and form of limb-bones it approximates closely to that genus; while what remains of the pectoral arch does not sanction its location in Elasmosaurus.
Elasmosaurus platyurus is regarded by Professor Cope as having been 45 feet long, one half of which length was formed by the neck, in which 69 vertebræ are preserved, and from which 3 more are supposed to be lost. The dorsal region is supposed to have contained 24 vertebræ, of which 14 are preserved, while in the tail there are supposed to have been 51 vertebræ, of which 21 are preserved, giving a total of 147 vertebræ. Mr. Gardner's fossil gives
