206 



four fossil species from the Portland stone, Kimmeridge clay, chalk 

 marl, and chalk. To these four species Dr. Buckland gives the fol- 

 lowing names : to that found in the Portland stone, Chimaera Town.' 

 sendii; lo that in theK\mmer\dgecVdy, C.Egertonii; to that in the chalk 

 marl, C. Agassizii ; and to that in the chalk, C. Mantellii. In an ap- 

 pendix to the paper, Prof. Agassiz gives the following as the distinc- 

 tive characters of each species : 



C. Townsendii : inferior maxillary very large, short and proportionally 

 much thicker; groove of the symphysis of its two branches shal- 

 lower, and curve of dental edge broader than in the other species ; 

 exterior surface convex, and furrowed longitudinally, intermaxillary 

 much curved. 

 C. Egertonii : inferior maxillary short and flat : snout truncated, and 

 in proportion very large: curve of the dental edgevery wide : groove 

 of the symphysis very deep : intermaxillary very much bent, and the 

 dental edge truncated and square : superior maxillary irregularly 

 triangular, much elongated, and contracted insensibly towards its 

 dental extremity, which is bifid. 

 C. Agassizii : form of inferior maxillary square, more regular, and sur- 

 face of symphysis flatter than in the other species ; dental edge 

 slightly open. 

 C. Mantellii : inferior jaw straighter and thinner; exterior surface 

 perfectly smooth and flat ; snout much elongated and pointed j 

 curve of the dental edge wider than in the other species. 



A paper was next read, '' On the recent discovery of Fossil Fishes 

 (Palcpojiiscus catopterus, Agasfi'iz,) in the new red sandstone of Tyrone, 

 Ireland ;" by Roderick Impey Murchison, Esq., V.P.G.S, 



A small specimen of new red sandstone, presenting the first Im- 

 pressions of fishes found in this formation in the British Isles, having 

 been exhibited before the Geological Section of the British Association 

 at the late meeting in Dublin, Mr. Murchison, in company with Prof. 

 Sedgwick, Lord Cole, and Mr. Griffith, visited the spot where it had 

 been obtained. 



The quarry is at Rhone Hill, in the parish of Killyman, about three 

 miles east of Dungannon. The new red sandstone in which it is ex- 

 cavated is a prolongation of the deposit which occupies large tracts 

 in the county of Antrim, and extends into this part of Tyrone, where 

 it surrounds a small, slightly productive coal-field, but reposes for the 

 greater part upon mountain limestone. The eastern flank of the di- 

 strict is covered by a vast thickness of clay, containing lignite, the 

 exact age of which is not known ; and the surface generally is very 

 much overlaid by loose detritus, consisting of sand and gravel, derived 

 from the adjacent formations. Large blocks of syenite and green- 

 stone, referrible to a northern origin (Antrim), are scattered here and 

 there. 



The beds of new red sandstone exposed in the quarry dip about 15° 

 to the N.N.E., and consist, in the upper part, of red and green marls, 

 passing down into a dark red, thickly bedded, siliceous sandstone, 

 with a few irregular, highly micaceous way-boards of a deep purple 



