248 PALEONTOLOGY 



of age is the Dimorphodon Banthensis, from the "Posidonomyen- 



schiefer" of Banz in Bavaria, answering to the alum shale of 

 the Whitby lias ; then follows the P. Bucldandi from the 

 Stonesfield oolite. Above this come the first-defined and 

 numerous species of Pterodactyle from the lithographic slates 

 of the middle oolitic system in Germany, and from Chin, on 

 the Phone. The Pterodactyles of the Wealden are as yet 

 known to us by only a few bones and bone fragments. The 

 largest known species are those from the upper greensand 

 of Cambridgeshire. Finally, the Pterodactyles of the middle 

 chalk of Kent, almost as remarkable for their great size, con- 

 stitute the last forms of flying reptile known in the history of 

 the crust of this earth. 



Order VII. — Thecodontia. 



Char. — Vertebral bodies biconcave: ribs of the trunk long 

 and bent, the anterior ones with a bifurcate head : 

 sacrum of three vertebras : limbs ambulatory, femur 

 with a third trochanter. Teeth with the crown mine 

 or less compressed, pointed, with trenchant and finely 

 serrate margins : implanted in distinct sockets. 



Genus Thecodoxtosaueus. 



Sp. Thccodontosaurus antiquus. — In 1836 certain reptilian 

 remains from the " dolomitic conglomerate" at Pedland, near 

 Bristol, were described by Messrs. Eiley and Stutchbury.* 

 The matrix has been referred to the Permian period ; it is 

 now 1 1m night by some good observers to be not older than the 

 triassic. 



The teeth in these reptilian fossils are lodged indistinct 

 sockets; they are arranged in a close-set series, slightly de- 

 creasing in size towards the posterior part of the jaw; each 

 ramus of the lower jaw contained twenty-one teeth. These 

 * Geological Transactions, 2d series, vol. v., p. 3 It 



