PALAEONTOLOGY I 'finds' made some years ago by Mr. H. M. Klaassen in the Lower Eocene Woolwich and Reading beds of the Park Hill railway cutting at Croydon constitute the chief point of interest in the palaeontological history of the county, so far as vertebrates are concerned. The first of these ' finds ' is one of the bones (ulna) of the fore-limb of a large primitive type of hoofed mam- mal referable to a genus first described by Sir R. Owen from the London clay of Essex under the name of Corypbodon, in allusion to the ridges capping the crowns of the molar teeth. By Mr. E. T. Newton, who described it, 1 the Croydon fossil is regarded as indicating a species dis- tinct from the one to which the Essex remains belongs, and it was ac- cordingly named Corypbodon croydonensis. The second peculiar form is a gigantic flightless bird, considerably superior in size to the ostrich ; it is represented by two imperfect bones of the leg, likewise obtained from the Park Hill railway cutting. These bones were also described by Mr. Newton, 3 who named the bird to which they belong Gastornis klaasseni, after the finder of the specimens. The genus Gastornis, it may be mentioned, was first established on the evidence of bones from Lower Eocene deposits at Bas-Meudon, in France, and was subsequently discovered at Rheims. Mr. Newton regards the English bones as indicating a species distinct from the one represented by the Meudon specimens. Whether Gastornis belongs to the same group of birds as the ostrich may perhaps be doubtful, as it is now ascertained that representatives of other groups have acquired a large bodily size concomitantly with the loss of flight. The limb-bones present a con- siderable resemblance in certain respects to those of the duck tribe. Corypbodon croydonensis and Gastornis klaasseni, together with the undermentioned Icbtbyodectes e/egans, appear the only extinct vertebrates peculiar to the county. The Surrey chalk has yielded remains of at least two species of reptiles and several kinds of fishes, and doubtless more remain to be dis- covered. The first reptile is Polyptychodon interruptus, of which remains from the chalk of the county were described by Sir Richard Owen. 3 This reptile was a swimming marine creature allied to the plesiosaurs of the Lias, but with a much shorter neck and larger head. In these respects it resembles the pliosaurs of the Jurassic strata, from which it differs by 1 Proceedings of Geologists' Association, vol. viii. p. 254 (1883). 8 Trans. Zoo/. Sec. London, vol. xii. p. 143 (1866). 3 Quart. Journ. Geol. Soc., vol. xvi. p. 262 (1860). 29
