Proceedings of the British Association. 365 



mens ; but it would be impossible, without plates, to convey to the 

 reader any accurate notion of these highly interesting organic re- 

 mains. They belong to two new genera established by Dr. Riley 

 and Mr. Stutchbury, the Palceosaurus and Thecodontosaurus ; and 

 were found in the magnesian conglomerate which at Durdham Down 

 reposes on the carboniferous limestone. They must have been de- 

 posited upon the spot where they were found without violent action, 

 as they bear no marks of attrition. Perhaps the most interesting 

 fact mentioned, was the peculiar structure of the vertebrae of the 

 newly discovered saurians, which presented a remarkable contrast to 

 those of the recent crocodiles. He shewed a singular gradation from 

 the recent saurians to sauroid fishes, by means of this arrangement 

 of vertebrae, which thus becomes an excellent guide in the discrimi- 

 nation of the saurian animals ; and he concluded his communica- 

 tion with a quotation from Agassiz, respecting the progressive de- 

 velopment of animal life. — Dr. Riley alluded to the extraordinary 

 structure of the cerebral column of these extinct saurians, as likely 

 to illustrate the supposition of Dr. Gall, that the spinal column of 

 vertebrate would be eventually found to correspond with the gan- 

 glionic system of invertebrate animals.— Dr. Buckland was particu- 

 larly struck with the singular structure of these vertebrae, as indica- 

 ting in the animal a nervous power of the most extraordinary char- 

 acter. 



A paper was read by Mr. Hopkins, containing theoretical views 

 respecting the geological phenomena of elevation. The principal 

 object of the author in this paper, was to investigate the eiFects of 

 an elevating force acting simultaneously at every point, on portions 

 of the crust of the globe of considerable superficial extent ; and to 

 shew that the theoretical inferences deduced from this hypothesis, 

 are in striking accordance with the phenomena he had observed in 

 the limestone and coal districts of Derbyshire. He also proved that 

 in that district the direct cases of dislocation were not such as could 

 result from the influence of the jointed structure as the determining 

 cause of those directions. He pointed out how the theory he had 

 discussed will account for nearly all the phenomena of mineral veins, 

 which can be attributed to mechanical causes ; as well as for the for- 

 mation of systems of anticlinal lines, of faults, and of the phenomena 

 of elevation. — Mr. Sedgwick considered this as the most important 

 communication as yet made to the Section. We should now be 

 enabled to indulge in the same speculations in Geology, as in her 



