304 Mr. Toulmin Smith on the Formation 



stand the statement that it " exhibits an appearance of having 

 been deposited in concentric layers, which are exposed by what 

 seems to have been an irregular decomposition of its surface/' 

 I beg, in the most explicit manner, to say, that not the slightest 

 appearance of the kind, in any respect whatever, is presented. 

 Let the reader glance over the description given on page 11 and 

 examine the plate, and he will at once see that the actual ap- 

 pearances are the most directly opposite and reverse of the alleged 

 appearances. The decomposing flints alluded to are not very 

 rare ; but in every respect whatever they totally differ, both in 

 external aspect and internal appearance and arrangement, from 

 the specimen described, of which all the edges are perfectly 

 sharp, the substance perfectly hard and in the highest state of 

 integrity, and the horizontal — and no trace of concentric — layers 

 very visible in some places. I have since obtained other fine 

 specimens of the same kind, all in an equal state of integrity, 

 and all therefore equally conclusive against the sponge theory. 



Mr. Bowerbank is much distressed at the idea of ^^ currents 

 and whirlpools. ■'■' If I gently give motion to a jug of water at 

 a given temperature, the whole mass assumes a form, as stated 

 in my former paper, very much like that on these specimens, and 

 the necessary " currents'^ excite no marvel. The motion among 

 the particles themselves causes the angular ridges. It is only 

 when the mass assumes special forms, as in fig. 1, that some 

 special motion must be suggested. Now I can show that such 

 slight, but sufficient, motions took place in the region of these 

 phsenomena, having been at the pains to collect specimens for 

 the purpose of establishing the point. Thus all the difficulty 

 vanishes. There are no " contrary currents in opposition to the 

 figured side,'' but precisely the reverse, as stated in my former 

 description of the specimen. 



As to the last-named specimen (fig. 1), it may not be amiss to 

 state that, as if to afford direct evidence of the truth of the views 

 advanced by me in explanation of the phsenomena exhibited by 

 that and similar specimens, I have been fortunate enough, since 

 that paper was written, to obtain a specimen exactly similar to 

 the part a in fig. 1, in the chalk. This proves the existence of an 

 absolute cause in that ocean sufficient for the production of such 

 forms. Now it is particularly interesting to find that, in this 

 chalk specimen, immediately underneath the chalk surface, 

 which was cleared from the block by my own hand, there is a 

 layer of flint — a capsule fitting into but below it, so that the 

 chalk impression is no mould, but a cap. This is beautifully 

 consistent with the suggested cause of the solidification of flint 

 under such circumstances, viz. the given motion. It further 

 suggests how the chalk impression remained firm after the mo- 



