58 Geological Society . 



close relation of the acts of upheaval and violent aqueous abrasion. 

 This necessarily implies the belief that the date of these lines of 

 disturbance is posterior to that of all the stratified beds of the south- 

 east part of England, as maintained in the author's former essays, 

 but into the full discussion of which he declines to enter till the 

 whole subject is before the Society. 



Jan. 20, 1841. — A paper was first read, " On the Teeth of Species 

 of the Genus Labyrinthodon {Mastodonsaurus Salamandroides, and 

 Phytosaurus (?) of Jiiger) from the German Keuper and the Sand- 

 stone of Warwick and Leamington," by Richard Owen, Esq., 

 F.G.S., F.R.S. 



The Warwick sandstone having been considered by some geolo- 

 gists to be the equivalent of the Keuper*, and by others of the 

 Bunter Sandsteinf, and as its true position remains to be deter- 

 mined, Mr. Owen, in the preliminary remarks to his memoir, points 

 out the assistance which the discovery of reptilian remains in the 

 Warwick sandstone of the same generic characters as those of fossils 

 obtained in the Keuper of Germany, may afford in determining the 

 question. 



Before he proceeds to describe the fossils forming the immediate 

 object of his paper, Mr. Owen shows that the genus Phytosaurus 

 was established on the casts of the sockets of the teeth of Masto- 

 donsaurus ; and that the latter generic appellation ought not to be 

 retained, because it recalls unavoidably the idea of the mammalian 

 genus Mastodon, or else a mammilloid form of the tooth, whereas all 

 the teeth of the genus so designated are originally and, for the 

 greater number, permanently of a cuspidate and not of a mammil- 

 loid form ; and because the second element of the word, saurus, 

 indicates a false affinity, the remains belonging, not to the Saurian, 

 but to the Batrachian order of Reptiles. For these reasons, and be- 

 lieving that he has discovered the true and peculiarly distinctive 

 dental characters of the fossil, he proposes to designate the genus by 

 the term Labyrinthodon. 



The only portions of the Batrachian found in the Keuper of Ger- 

 many, which have hitherto been described, consist of teeth, a frag- 

 ment of the skull, and a few broken vertebrae ; and in the Warwick 

 sandstone of teeth only. In this memoir, therefore, Mr. Owen 

 confines his attention to a comparison of the dental structure of the 

 Continental and English remains. The teeth of the Labyrinthodon 

 Jaegeri {Mastodonsaurus Jaegeri, Meyer) of the Keuper are of a 

 simple, conical form, with numerous fine longitudinal striations ; 

 and the teeth transmitted to Mr. Owen from the Warwick sandstone 

 by Dr. Lloyd, bear a very close resemblance to them. Their external 

 characters not being sufficient to establish either specific or generic 

 identity, Mr. Owen had sections prepared for microscopic examina- 

 tion of portions of teeth of the Labyrinthodon Jaegeri forwarded to 

 him by Prof. Jager, and of the English reptile ; and though, from 

 his previous examination of the intimate texture of the teeth of the 



* See Proceedings, vol. ii. p. 453. f Ibid, vol. ii. p. 565. 



