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been found in the Kimmeridge clay of Market Rasen, Weymouth, 
and Shotover. From differences in the relative proportions of 
_ these bones, Prof. O. considers them to have belonged to two 
~-» distinct species of Pliosaurus. The remains of the Saurians of 
the crocodilian family, which complete the transition from the 
Hnaliosaurians to the terrestrial lizards, were next noticed. The 
Report included descriptions of the fossil crocodiles in the British 
| formations below the eocene tertiary strata_to the oolite inclu: 
sive ; and it was observed, that the extinct Species deviated from 
the organic type of the existing crocodiles, in proportion as their 
remains occurred in strata geologically more remote from. the 
present time. Not any of the species were identical with those 
now known to exist, and the modifications of structure in which 
they differed, were much more considerable than any which dis- 
tinguish the skeletons of existing species from each other. The 
extinct species agreeing with the present crocodiles in possessing 
the ball-and-socket articulation of the vertebre, in which the 
cavity is on the fore part, were first described. Of these, the 
Crocodilus Toliapicus is found in the London clay of Bracklesham, 
at Sheppey, and in beds of sand underlying the red crag at Ky- 
son. 'The Crocodilus cultridens of the Wealden formation Prof. 
O. now considered sub-generically different from the crocodiles, 
and proposed for it the name of Suchosaurus. Grontopholis cras- 
| sidens, another species from the Wealden, was described by Prof. 
O./as more completely mailed than any of the crocodile family ; 
its remains occur in the Tilgate Forest and near Battle Abbey, 
aud in the Purbeck limestone at Swanage. The next family of 
extinct cro¢odilians considered by Prof. Owen, are characterized 
by the biconcave structure of the vertebrae. Remains of the 
first of these, Teleosaurus Chapmanni, are abundant in the lias 
of the Yorkshire coast; and 7’. Cadonensis, which abounds in 
the oolitic formations near Caen, in Normandy, also occurs in the 
Oolite near Woodstock, and at Stonesfield. Remains of two other 
Species were noticed. ‘T‘he second genus, Steneosaurus, distin- 
guished from the last by the sub-terminal position of the nostril, 
is fromthe Kimmeridge clay at Shotover, and from the oolite of 
Stonesfield. One of the most interesting specimens, exhibiting 
the form of the brain in a cast of that part, is in the Woodward- 
. jam Collection at Cambridge. A third division was for the- 
time described as occurring in British strata, possessing the ball- 
Vol. xx, No. 2.—Jan.-March, 1842. 42 
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