Geological Society of London, 233 



IL~Marcli 22, 1876.— Professor P. Martin Duncan, M.B., F.R.S., 

 President, in the Chair. 



1. " On the Triassic Strata which are exposed in the Cliff Sections 

 near Sidmouth, and a Note on the Occurrence of an Ossiferous Zone 

 containing Bones of a Lahyrinthodon.'' By H. J. Johnston Lavis,. 

 Esq., F.G.S. 



The author described the base of the cliffs east of Sidmouth as 

 composed of the Marl which is the uppermost subdivision of the 

 Trias in South Devon, capped in Littlecomb Hill and Dunscomb 

 Hill by Greensand and Chalk, and in Salcombe Hill by Greensand 

 alone. In the valley of the Sid it is largely exposed at the surface. 

 Close to the mouth of the Sid the Upper Sandstone crops out beneath 

 the marl, forming a cliff overhanging the river; To the west of 

 Sidmouth there is a low projecting cliff, the Chit rock, formed also 

 of the Upper Sandstone, and at the western end of this is a fault 

 which has given the Chit rock an upthrow of at least 40 and perhaps 

 of 80 feet, since it has no marl capping it, and in its lithological 

 character it resembles the middle part of the Upper Sandstone. To 

 this point the dip is to the east ; but westward of the fault the dip 

 iJ^at first to the west for about half a mile, when the sandstone reap- 

 pears with an easterly dip, having formed a synclinal curve. It is 

 overlain by Marl and Greensand in Peake and High Peake Hills, 

 which are capped with Chalk gravels. West of High Peake Hill 

 the Sandstone forms the whole cliff. The author described the 

 general characters presented by the Triassic beds in the section 

 under notice, and mentioned the occurrence at about ten feet from 

 the top of the Sandstone of a peculiar series of beds, composed of 

 coarse sandstone, containing scattered nodules of marl from the size 

 of a pea to that of a hen's egg, together with numerous fragments of 

 bone, some of which, belonging to a species of Zahyrinthodon, would 

 be described by Prof. Seeley. The author mentioned that he had 

 received from the Eev. S. H. Cooke some fragments of bone obtained 

 by him twentj^ years ago from this same ''Ossiferous Zone." Mr. 

 Whitaker's specimen of Hyperodapedon was also obtained from the 

 Upper Sandstone. 



2. " On the Posterior Portion of a Lower Jaw of Lahyrintliodon 

 (L. Lavisi) from the Trias of Sidmouth." By Harry Govier Seeley, 

 Esq., E.L.S., E.G.S., Professor of Physical Geography in Bedford 

 College, London. 



After referring to the doubtful position of the Labyrinthodontia in 

 the system, and expressing his doubts as to the occurrence of the 

 genus Mastodonsauriis in Britain, the author proceeded to describe 

 in detail the posterior part of the right ramus of the lower jaw of a 

 Labyrinthodont, obtained by Mr. Lavis from the Ossiferous Zone of 

 the Trias near Sidmouth, the position of which was described by 

 that gentleman in the preceding paper. The specimen, which is 

 13 inches long, and perfectly free from matrix, shows that the 

 lower jaw in Labyrinthodonts not only contains articular, angular, 

 and dentary elements, as hitherto suj^posed, but also separate sj)he- 

 nial and surangular elements, and probably a distinct coronoid bone. 



