337 



from the close resemblance in the forms of the vertebrae. It ap- 

 pears to have been about twice the size of the Plesiosaurus found 

 at Lyme, and described by Conybeare in the Transactions of the 

 Geological Society *. The animal is lying on its left side with the 

 vertebrae and the bones of the shoulders and pelvis nearly in situ, 

 but the ribs and the bones of the extremities are somewhat broken 

 and detached. The vertebral column has the gentle sigmoid flexure 

 we observe in the Ichthyosaurus, being concave before in the dorsal 

 region, and concave behind in the region of the pelvis. The bodies 

 of the vertebrae lie in close contact with each other, and about 

 fifty-nine may be estimated as forming the part of the column from 

 the anterior dorsal vertebra to the end of the tail, which is nearly 

 the same number as that observed in the corresponding part of the 

 specimen from Lyme. Judging from the appearance of the first 

 dorsal vertebra, which is exposed and a little worn, the author con- 

 cludes that the bodies of the vertebrae present flat surfaces to each 

 other, as in those described by Cuvier from Honfleur. The an- 

 nular part of the vertebrae is anchylosed to the body of the bone, 

 as in the species from Honfleur.. The tubercular expansions of 

 the transverse processes of the dorsal vertebrae are all directed 

 downwards, and not, as in that described by De la Beche and Cony- 

 beare, pointing upwards in the middle of the series. The right 

 coracoid bone is pushed down from the head of the humerus, and 

 the expanded bones of the pelvis are thrown forwards to some di- 

 stance from the vertebral column. One of the arms is pretty en- 

 tire, and the author considers the flattened form of the bones as 

 indicative of the aquatic life of the animal. The scapula exhibits 

 a suture dividing it into two parts, and the head of the humerus 

 presents a distinct protuberance, for the attachment probably of 

 the pectoral muscles. One of the sacral extremities is detached 

 and inverted, having the tibia and fibula lying next to the pelvis ; 

 the other sacral extremity appears to be concealed by the broad 

 bones of the pubis. The author has given as full an account of 

 all the bones of this interesting animal as the hardness of the im- 

 bedding rock, or the safety of the specimen, would allow of their 

 examination. 



A letter was then read, addressed to the President and Fellows 

 of this Society, " On the ancient and present state of Vesuvius," 

 by Count de Montlosier, For. Mem. G.S. President of theAcademy 

 of Clermont Ferrard, &c. &c. 



The author offers this short notice on Mount Vesuvius in testi- 

 mony of the grateful sense entertained by him of having been 

 elected Foreign Member of the Geological Society; and the present 

 communication is intended to convey his opinions, formed during 

 a visit to Naples in the year 1813, in respect to the age and origin 

 of Mount Vesuvius, and of its neighbour Monte Somma. 



Having pointed out the direct analogy between the active vol- 

 cano of Vesuvius, and the extinct volcanoes of Auvergne, formerly 



* Geol. Trans. 2nd Series, vol. i. p. 381-389. pi. 48. 



