﻿ANNIVERSARY ADDRESS OF THE PRESIDENT. lix 



development, arguing that these tribes, possessing as they do a high 

 grade of organization (although by no means the highest among the 

 mollusca), came latest in the order of creation, or were not formed until 

 the tertiary epoch. It is therefore important that we should have made 

 so large an accession of fossils referable to this division, some of the 

 species approaching very closely in their forms to living English shells, 

 in strata of such antiquity ; for the recent researches of Prof. Forbes 

 leave little doubt that the Purbeck belongs to the oolitic type, judging 

 from its intercalated marine shells and echinoderms, whereas the ma- 

 rine mollusca of the Hastings sands, collected by Mr. Austen, imply 

 that that division of the Wealden has a closer affinity to a lower cre- 

 taceous fauna. According to this view, the genera Planorbis, Lym- 

 neus, Valvata, Physa, and others, are at once carried down from the 

 eocene group to the oolite, and such a fact should for ever warn us 

 against reasoning in future on mere negative evidence, as to the non- 

 existence of all similar families of mollusca in the primary periods. 



In speaking of the Vertebrata of the secondary rocks, I need only 

 observe respecting the fish and reptiles, that they were most fully 

 developed in their organization, the Iguanodon and some other con- 

 temporary saurians making even a nearer approach in many characters 

 of their osteology to warm-blooded quadrupeds than any reptiles now 

 living on the globe. The only points therefore in secondary palaeon- 

 tology to which it seems necessary to allude are, first, the foot-prints 

 of birds in the trias of North America, secondly, the fossil mammalia 

 of the Stonesfield oolite, and thirdly, the extreme scarcity, if not entire 

 dearth, at present, of cetaceous remains in rocks older than the eocene. 



First, as to the age of the red sandstone containing bird-tracks in 

 the valley of the Connecticut river, I have little doubt that this rock 

 is at least as old as the European trias. It contains several species 

 of fossil fish of the ganoid genus Ischypterus of Egerton, by which it 

 is distinguished from those coal-bearing strata of oolitic or liassic 

 age, near Richmond in Virginia, which I have described in the third 

 volume of your Quarterly Journal. The genus Ischypterus is of a 

 peculiar type, and therefore of small value in settling a chronological 

 question, but the want of a decidedly heterocercal tail may perhaps 

 raise some presumption against their being Permian. That they 

 are newer than the true or primary coal-measures may be deduced 

 from still more satisfactory data. The old carboniferous formation 



