Geological Society. 315 



This remarkable change of malic acid salts into those of 

 fumaric acid, appears to me to bear a strong analogy to the 

 formation of the pyro- and metaphosphates, but this is as yet 

 not sufficiently proved by experiment. I have kept a satu- 

 rated solution of fumaric acid at a boiling temperature for 

 several days without the slightest change in it. And I have 

 also kept a like solution, in a tube hermetically sealed, for a 

 considerable time at a temperature of 250°, under a pressure 

 therefore of nearly 15 atmospheres, without its being altered 

 in any of its properties. Hence fumaric acid does not appear 

 to be inconvertible into malic acid. 



XLVI. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 175.] 



Jan. 20, \ PAPER was first read, " On the Teeth of Species 

 1 84 1 . /*■ of the Genus Labyrinthodon (Mastodonsaurus Salaman- 

 droides, and Phytosaurus (?) of Jager) from the German Keuper and 

 the Sandstone 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 tbe preliminary remarks to his memoir, points 

 out tbe 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- 



* See Proceedings, vol. ii. p. 453. [or Phil. Mag., Third Series, vol. xi. 

 p. 106.] 



f Ibid. vol. ii. p. 565. [or Phil. Mag., Third Series, vol. xi. p. 320.] 



