

198 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. III. 



not to the juncture of two vertebrae, nor to the extremity 

 of the body, but to the middle of the centrum. 1 



VERTEBRAE OF MOSASAURUS, from the chalk near Lewes. 

 (M. /Stenodon.) Wall-case A-B. On the recess above the 

 specimens of Geosaurus, is a small block of chalk, to which 

 are attached two caudal vertebrae, possessing the characters 

 above described, and by which I was enabled to identify them 

 with the corresponding bones of the celebrated Maestricht 

 reptile, of which I had then read, but never, in my most 

 sanguine moments, had indulged the hope of finding any 

 vestiges in my native hills. 2 A posterior dorsal vertebra from 

 the same locality is placed near them ; I have subsequently 

 obtained a caudal vertebra imbedded in flint (from near 

 Brighton) ; a few other portions of the vertebral column 

 have, I believe, been collected from the Sussex chalk since 

 my removal from Sussex. The remarkable character above 

 pointed out, of the coalescence of the chevron-bone with 

 the body of the vertebra, is well shown in these two caudals 

 from Lewes. M. Cuvier observes, that there is no known 

 reptile in which this bone is soldered to, (" soude"), and makes 

 a part of, the centrum; it is a character peculiar to fishes, and 

 must have greatly augmented the solidity of the tail. 



No teeth similar to those in the jaws of the Mosasaurus have 

 been obtained from the English chalk ; but some large smooth 

 conical teeth of an acrodoiit reptile, symmetrically elliptical 

 like the pterygoidal teeth of Mosasaurus, were found in the 

 same stratum as the vertebrae, and are probably referable to 

 the same species. In 1831, a portion of the lower jaw with 

 teeth of a similar character, was found in the chalk near 

 Norwich, and of which I received drawings from the late 

 Mr. Samuel Woodward. Other specimens of equilateral 



1 " Elles fonnent une grande partie de la queue, et les faces de leur 

 corps sont en ellipses, d'abord transverses, et ensuite de plus en plus 

 comprimees par les cotes. L'os en chevron n'y est plus articule, main 

 soude, etfait corps avec elles" Ossemens Foss. loc. cit. p. 327. 



2 In "The Fossils of the South Downs; or, Illustrations of the Geo- 

 logy of Sussex," 1822, there are figures and descriptions of these speci- 

 mens, pp. 242246 ; tab. xxxiii. and xli. I would especially direct the 

 observer's attention to the deep incision observable on the posterior 

 vertebra in this specimen, which must have been made before the bones 

 were imbedded in the chalk. 



