234 Geological Society : — 



consists of two biconcave vertebral centra. The strata wherein they 

 were discovered were described, and the reptilian remains hitherto 

 found in them briefly referred to. The form and structure of these 

 vertebrae were then described in detail, and contrasted with those of 

 the vertebrae of other Enaliosaurians and of Plagiostomous fishes ; 

 and it was stated that, with the exception of these, no Enaliosaurian 

 remains have as yet been found in strata older than the Trias. 



2. " Description of Anthracosaurus, a new genus of Carboniferous 

 Labyrinthodonts." By Professor T. H. Huxley, F.R.S., F.G.S. 



Anthracosaurus is distinguished from all other known Labyrintho- 

 donts by the quadrate form and oblique position of the orbits, by the 

 existence of elongated supratemporal foramina, and by the compara- 

 tively small number and large size of the teeth. The skull exhi- 

 bited had an extreme length of 15 inches, and an extreme width of 

 12 inches. There are about thirty maxillary, two vomerine, and ten 

 palatine teeth, which are ridged and become flattened and two- 

 edged towards their apices. The vomerine, palatine, and some of the 

 anterior maxillary teeth are between 2 and 3 inches long, and from 

 | to J of an inch in diameter at the base. The species exhibited 

 was named A. Russelli, after its discoverer. Probably its entire 

 skeleton had a length of not less than 6 feet. 



3. "On the Thickness of the Pampean Formation near Buenos 

 Ayres." By Charles Darwin, Esq., M.A., F.R.S., F.G.S. 



Some sections of Artesian wells sunk in this formation showed 

 its entire thickness near Buenos Ayres to be about 210 feet. It 

 was stated to rest upon various marine beds upwards of 100 feet 

 thick, ' containing Ostrea Patagonica, Ostrea Alvarezii, Pecten Para- 

 nensis, &c. These reposed upon red calcareous clay, which was 

 bored through to a depth of 213 feet more, contained no fossils, and 

 is of unknown age. 



4. " Geological Notes on the locality in Siberia where Fossil 

 Fishes and Estheria were found by Dr. Middendorf." By C. E. 

 Austin, Esq., C.E., F.G.S. 



These^fossils were obtained from a bed of shale in a low cliff 

 about 200 versts south of Nertschinsk, forming the west bank of 

 the Tourga, a small tributary of the Paver Onon. The author gave 

 a detailed section of the cliff, and noticed the volcanic and sedi- 

 mentary rocks of the district, and more especially referred to the 

 far-famed, gem-containing granite of Odon-Tchalon. 



5. " Note on Estheria Middendorfii." By Professor T. Rupert 

 Jones, F.G.S. 



The locality whence this Estheria was obtained was described in 

 the former paper. The carapace was stated to approach in cha- 

 racter to that of E. Dahalacensis, which lives in the freshwater 

 marshes of Dahalac and in the Tigris. It was concluded that the 

 deposit in which this fossil occurs is of freshwater formation, and 

 probably of Tertiary date. 



