REPTILES OF THE CHALK. 
147 
ton of tliis animal, are figured and described in the 
s])endid work on the fossils of that mountain, by 
Faujas St. Fond; and the nature of the original, has 
since been ably elucidated by M. le Baron Cuvier. 
These remains have not jireviously been noticed 
in England; and have been found in Europe in the 
immediate vicinity of Maestricht only, where they 
occur in a soft, yellowish, calcareous freestone. 
This limestone reposes upon the flinty chalk, and 
contains beds of flints perfectly resembling those of 
the chalk formation. 
The vertebra? here represented are from the 
U])per chalk near Lewes ; and, being found in the 
same quarry; and at a short distance from each 
other, may probably have belonged to the same in- 
dividual. Like those of the crocodile^ monitor, 
iguanas, and the greater part of the saurian animals, 
they have the body convex posteriorly, and con- 
cave anteriorly : a structure that distinguishes 
them from those of the cetacea and fishes. 
Fig. 2. appears to correspond most completely 
witli the posterior dorsal vertebne in the spinal 
column of the Maestricht monitor, figured by Fau- 
jas, PI. 52. ; particularly with the third and fourth 
vertebne, reckoning from the left hand of the speci- 
men. The body of the vertebra is rather compressed, 
. about two inches long, and 1 *4 inch high ; the face 
is slightly elliptical. The convexity of the poste- 
rior extremity is but slight, and the concavity of the 
« opposite side of a corresponding depth, the surface 
I being perfectly plain and smooth. The spinous 
I process, of which a fragment only remains, is com- 
