248 FOSSIL REPTILES. 



sort of grey marie or tuphous chalk, a bluish argillaceous marie 

 analogous to that of Havre, the green sand, an argile contain- 

 ing beds of hmestone, which we call Sussex marble, and, lastly, 

 the ferrugineous sand which is so much extended throughout all 

 this country. 



The different strata are situated obliquely, so that the lowest 

 rises on the eastern side, and forms plateaus as high as those 

 of the chalk on the western side ; on one of which the forest 

 of Tilgate is situated, so that the ferrugineous sand is imme- 

 diately under the diluvial or superficial stratum. 



Amidst innumerable remains of testacea, Crustacea, and 

 fish, this sand also contains an abundance of reptiles' bones, 

 and especially those of tortoises and crocodiles. There are 

 many teeth, vertebrae, and other bones of the latter. Many of 

 the megalosaurus, to be noticed hereafter, and especially some 

 very singular teeth belonging to a reptile, but which are worn 

 by detrition, as in the herbivora. 



The vertebrae are a little concave at the two extremities, 

 which approximate them to the crocodile of Caen, and the 

 second of those of Honfleur. They are, however, nearer the 

 first. The teeth are, for the most part, more obtuse than those 

 of the common crocodiles. 



In the deposition of lignites and plastic argile at Auteuil, 

 near Paris, some small remains were found belonging to this 

 genus. This formation is much more ancient than that of 

 Montmartre, where there were also found a frontal and muti- 

 lated humerus of crocodile. In the lignites of Provence was 

 found the upper part of a femur, which M. Cuvier seems to 

 regard as having belonged to a peculiar species. In the isle 

 of Sheppey, a cervical vertebra was found by M. de Luc, and 

 determined by the Baron. 



It is remarkable that crocodiles equally resembling the 

 living species, accompany the palaeotheria and lophiodonta in 

 the fresh-water calcareous formation as well as in the gypsum ; 

 and what, perhaps, is still more surprising is, that they are 

 found there with trionyx. 



