3 Mr. Toulmin Smith on the Formation 



the bodies themselves whence the flints are said to derive their 

 forms are almost wholly, often wholly, gone, and yet in those 

 very flints are preserved structures, as we shall see, in endless 

 variety, every whit as delicate and beautiful as the sponges them- 

 selves, and that too of bodies which, according to the very as- 

 sumption of the theory, were themselves dead before the sponge 

 was formed over them ? 



But it may further be asked, how happens it that there are 

 found in flints fragments perfect and in beautiful preservation of 

 the reticulated tissue, while all the rest is wanting ? This is in- 

 consistently enough an admitted fact, — a fact itself proving that 

 the destruction of this tissue, assumed to have taken place in all 

 but these fragmentary places, is not a necessary or easily explain- 

 able fact. These fragments generally show under the micro- 

 scope a clear and distinct tor7i edge, not a going-ofi" into gradual 

 indistinctness as would be the case if they were the remnants of 

 a large body formerly filling the place of the flint. I can readily 

 understand that fragments of sponges might float about in the 

 ocean mud and become, with other organic remains, imbedded and 

 preserved in flint. We find precisely such fragments in the chalk 

 also. Such a view fully accounts for the presence of these frag- 

 ments in the flints, while their presence in that fragmentary state 

 is totally inconsistent with the idea of the whole mass of flint 

 having ever been made up of such tissue. 



Moreover, perfect sponges do exist among the flints. These 

 however assume a totally different aspect and form to ordinary 

 flints. I have several specimens, in which the general form of 

 the sponge, with its roots, is perfectly preserved, and the struc- 

 ture very beautifully displayed on fracture ; and, placed side by 

 side with a fine specimen of recent sponge, the one seems but 

 the solidified representation of the other. Not so the flint nodules 

 or tabular masses. They assume every variety of fantastic form, 

 . while it is admitted that roots, or traces of them, are not to be 

 found. 



We advance now to another and distinct branch of the in- 

 quiry; namely, as to the evidence afforded by the organic re- 

 mains, undoubtedly other than sponges, which are found in 

 flints : and I think we may derive equally conclusive evidence 

 from this class of facts. 



Where, in recent sponges, do we find the innumerable quan- 

 tities of shells and other large objects that we find in the chalk 

 flints ? In a specimen now before me, by no means a picked one, 

 I find projecting from the exterior two Plagiostomas, a Tere bra- 

 tula, a Pecten, twelve Ostreas and several Serpulas ; all these ob- 

 vious ; besides innumerable smaller shells and several portions of 

 a quadrangular Ventriculite. This specimen is about 8 inches 



