26*2 



THE GEOLOGIST. 



nera Pterychthys, Coccosteus, &c., and referred to in M. A^assiz's me- 

 moir ; he also mentioned the remains of gigantic fishes aUied to the Pte- 

 richthys, which had been discovered in Russia; he beheved that M. 

 Agassiz would be obliged to modify his statement of the comparative 

 insignificant dimensions of the fish found in the older rocks. He re- 

 marked, that it would scarcely be safe, in the present state of our know- 

 ledge, to draw divisions in strata upon zoological evidence only. In 

 that case, the occurrence of fish in the upper Silurian strata would 

 make it necessary to include those deposits in the old red sandstone. 

 The evidence of Mr. Owen, in his Report on Fossil Saurians, and that 

 of M. Agassiz in the present Report, agreed in disproving the transmu- 

 tation of species, in passing from one stratum to another. 



Mr. Sedgwick referred to a recent statement by Professor Owen, 

 that the remains of an Ichthyosaurus found in the lower chalk, green- 

 sand and gault, were identical with those of a species common in the 

 lias, showing a greater range than had ever been suspected in an animal 

 so highly organized. 



Sir H. De la Beche stated, that from all our knowledge of the dis- 

 tribution of species, and their continued existence from one deposit to 

 another, he was disposed to doubt the statement of M. Agassiz, as to 

 the limited range of species. He could not regard the fish of the ter- 

 tiary as entirely distinct from those of the present time ; yet he believed 

 that M. Agassiz regarded not merely the fish, but the shell of the ter- 

 tiary, as altogether distinct from the existing Fauna. 



Mr. Phillips observed, that the amount of reliance to be placed upon 

 M. Agassiz's views of the distribution of fish in the older rocks, must 

 depend upon the degree of completeness of that evidence. A few years 

 ago, comparatively little was known ; now we are acquainted with more 

 than eight hundred forms. The state of our knowledge of fossil fish 

 was still imperfect, and in order to make the evidence given by it of 

 equal value with that of other departments of zoology, ten times the 

 amount of research would be needed. And not merely were the data 

 insufficient as regarded the old rocks which had been the especial objects 

 of examination, but the strata of Russia and many other countries where 

 fish remains were found, must be examined and brought into compari- 

 son with the results previously obtained, before we should be justified 

 in adopting such views as some of those entertained by M. Agassiz. 

 Mr. Phillips proceeded to describe some remains of a small fish resem- 

 bhng the Cheiracanthus of the old red sandstone, scales and spines of 

 which he had found in a quarry at Hale's End, on the western side of 



