.1822.] . Geological Society. 69 
tion, but the author hesitates to pronounce any decisive opinion 
as to the question, whether it approximates most nearly to the 
former or the latter class; considering its characters as in 
many respects intermediate, and the combination. of those 
characters as constituting a whole entirely sui generis. 
In the course of this detail, the structure of the temporal 
fosse, the parts surrounding the meatus auditorius, the pos- 
terior bones of the head, and the palatal and pterygoidal parts 
of the roof of the mouth, are minutely investigated. 
Of the new Saurian genus Plesiosaurus (tie discovery of 
which is due to the present author), the bones of the head 
which had not been discovered when the former communication 
was published, have since been procured. The teeth in this 
genus are placed in distinct alveoli, and in all respects resemble 
those of the crocodile ; but in almost every other respect, the 
- analogies presented by the head of this animal are much more 
closely allied with the lacertian genera. 
The nostrils are small, and placed as in the Icthyosaurus ; 
so that the olfactory organs must have been much less deve- 
loped than in any recent Saurians. 
The comparative} shortness of the snout in the Plesiosaurus 
ives to the whole head a-general character entirely dissimilar 
to that of the Icthyosaurus, yet many of its separate parts offer 
strong analogies with this genus also, 
May 17.—Notice on a Fossil Bone found in the neighbour- 
hood of Cuckfield, Surrey, by Capt. Vetch, MGS. 
The bone mentioned in this notice was obtained from a bed 
of ferruginous sandstone, a short way north of Cuckfield in 
Sussex; this bed is 6 feet thick, resting upon blue clay, about 
3 feet from the surface ; and within the sandstone is a bed of 
limestone, about a foot thick; and the bone, under examina- 
tion, was found at the upper junction of the limestone and 
sandstone partly imbedded in both. The bed of sandstone 
varies considerably in its thickness and dip; and the beds of 
limestone which it contains also vary in thickness and num- 
ber. These two rocks contain vegetable remains, shells, and 
numerous small fragments of bone. That under notice is, how- 
ever, of considerable size, but was evidently at the period of 
its envelopement in the sandstone, very imperfect. 
The fact of the bones in this bed being so much broken and 
dispersed, would seem to show that they had been subjected 
to the action of some considerable force, probably of water; 
and as the fragments have not the appearance of being water 
worn, it may have been, that the bed of sandstone is not their 
original repository, but they had been lodged in a previous bed 
of sand or mud, till so far decayed as to be easily broken by 
slight forces. 
rom the appearance and internal structure of the bone under 
consideration, it may, the author conceives, be inferred, that 
