THE ANIMAL KINGDOM. 61 



dominant idea? Certainly not. There is nothing but utter 

 feebleness in these presumptuous theories, the audacity of 

 which now-a-days alone makes them successful. 



We have placed the flint and sponge together, one of 

 the hardest of our stones with one of the softest of animals, 

 because the one seems in some cases to be only a transfor- 

 mation of the other. 



Certain sponges, in lieu of having a soft and horny 

 framework, are only composed of little hollows or fibres of 

 flint, and accordingly, so far from showing the flexibility of 

 those we ordinarily use, they are excessively fragile, and 

 the least pressiu^e breaks them like glass. 



When this peculiarity is taken into account, the proxi- 

 mity of the sponge to the flint appears less extraordinary, 

 for the detritus of the zoophyte was adequate to produce 

 the other by its condensation. Indeed, some geologists 

 think that the flints of the chalk proceeded, if not entirely, 

 at least in great part from the sponges and Infusoria which 

 inhabited the cretaceous seas. The flints of some coun- 

 tries even contain the debris of sponges; they are also found 

 in the jaspers and agates.' " ' 



Thus a connection is established between one of the 

 most fragile organisms in creation, and one of the hardest 

 rocks — the sponge and the flint. 



1 It is to Mr. Bowerbank that we are iujebtej for having shown that the flints 

 of different localities contain the remains of sponges. He also demonstrated that 

 the moss-agates of Germany and Sicily owe the peculiarity from which tliey are 

 named to the presence of sponges. — Trans. Geol. Hoc. v. 4. 



Lyell, speaking of flint, says, "As to that found in the tripoli and flint of the 

 chalk, it may be looked upon as proceeding, in great part at least, if not entirely, 

 from the decomposition of the Infusoria, sponges, and divers other bodies." — 

 Nouveaux Elements de Geologie. Paris, 1837, p. 99. 



