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PALiEONTOLOGY Passing on to the consideration of reptiles from formations older than the Oxford Clay, we find remains of the long-snouted crocodile known as Steneosaurus brevidens occurring not uncommonly in the Great Oolite of the county ; teeth referable to some species of the same genus have been found in the Cornbrash near Peterborough ; while bones and teeth assigned to S. chapmam have been recorded from the Upper Lias of Green's Norton, near Towcester, and those of 6". latifrons from the same formation near Northampton. These and other crocodiles from the Oolitic deposits differ from the existing members of the group in that both the terminal articular faces of their vertebra are concave, instead of alternately convex and concave. From the Great Oolite of Blisworth the British Museum possesses two caudal vertebrae of a dino- saur which has been named Cetiosaurus oxoniensis, but whose proper title is apparently Cardiodon oxoniensis. In the same collection are two other caudal vertebrse from the Forest Marble of Cogenhoe which have been assigned to C. glymptonensis. Teeth of the great carnivorous dinosaur Megalosaurus bucklandi, now in the British Museum, were discovered by Mr. Sharp in the Inferior Oolite of Duston. A vertebra of Ichthyosaurus was obtained so long ago as 1837 from the Upper Lias of Blisworth, while a humerus of the same genus is recorded from the Lias of Bug- brook. The Lower Jurassic strata of Higham Ferrers have also yielded a vertebra of Pliosaurus, and remains of the allied genus I'haumatosaurus occur in the Upper Lias of Kingsthorpe and Crick, as well as in the Marlstone, or Middle Lias, of Bugbrook ; the species from the two last-named localities being Th. propinquus. Plesiosaurian vertebra like- wise occur in the Cornbrash of Rushden. Fish remains, at all events in a determinable condition, do not appear to be very abundant in the Lower Oolites of the county. The pavement-toothed sharks (Cestraciontida), now surviving in the form of the Port Jackson species, are represented by palates of Asteracanthus acu- tus and Strophodus magnus from the Cornbrash, and by the last-named species and iS". tenuis from the Great Oolite of the county. Another genus of ganoid fishes, the well-known Lepidotus, with spherical button-like palatal teeth and shining rhomboidal scales, is represented in the Middle Lias of the county by L. elvensis, and in the Great Oolite by L. tuberculatus. A ganoid at present peculiar to the Inferior Oolite of Northamptonshire is Ophiopsis Jiesheri, of which the type specimen was obtained from the railway tunnel near Blisworth. The pycnodont ganoids, which have numerous crushing teeth, frequently showing a sculptured pattern on the palate, are represented in the county by two species of the genus Mesodon {M. ruguhsus and M. bucklandi) from the Great Oolite. The invertebrate fossils of the Northamptonshire Oolites were worked out in great detail about thirty years ago by Mr. S. Sharp, and the results published in the Quarterly "Journal of the Geological Society^ for ' Vols. xxvi. p. 354, and xxix. p. 225. 43