388 Proceedings of the British Association. 



order to understand this succession ; and if these fossils had 

 really lived in all the etages of a formation, it would be difficult 

 to conceive how certain very thin beds of great extent do not 

 contain on their surfaces, at different intervals, evident traces of 

 life, and of the existence of the organised beings, whose debris 

 we find in the inferior strata, as we find, for example, rolled 

 blocks, fragments of wood, &c. The state of conservation of co- 

 prolites, which has been advanced as a proof of the existence of 

 saurians, around which they are found, seems, to M. Agassiz, to 

 prove, on the contrary, that these substances have only been de- 

 posited during the agonie of the animals from which they were 

 derived ; for if they had not been enveloped in the strata which 

 contain them, at the very moment when they were deposited by 

 the animal, it would be inexplicable how we should find bodies 

 so soft still entire, even after being a few hours in the water. 

 Whenever evident traces of slow deposition occur, M. Agassiz 

 believes that such beds should be attributed to periods of com- 

 parative repose, 'and not to formations which have had their 

 origin during cataclysms, in consequence of which the earth 

 has assumed another aspect. It would, therefore, be of import- 

 ance to distinguish more precisely the different effects produced 

 by destructive causes, which have acted at the surface of the 

 earth. These causes seem to M. Agassiz connected with the na- 

 ture of the earth, and dependent on its particular organization, 

 much rather than on its external relations with other celestial 

 bodies, and their influence at its surface. 



Captain Portlock exhibited specimens of a fossil fish from the 

 new red sandstone of a quarry near Roan Hill, Dungorman, 

 parish Killyman, county of Tyrone. M. Agassiz stated, that 

 the fossil belongs to the genus Palasoniscus ; but that it consti- 

 tutes a new species, remarkable from the dorsal and anal fins 

 being placed very far back, and from the dorsal being nearer 

 the anal than in the other species. The form is very elongated. 

 The discovery of this fish is the more interesting, as it extends 

 the geological limits of the genus Palasoniscus, of which the 

 species hitherto known have been found only in the coal forma- 

 tion and in the magnesian limestone. M. Agassiz proposes to 

 give to this new species the name Palasoniscus catopterus. Mr 

 MurchisOn, after pointing out to the Section how successfully 



