13 Mr. Toulmin Smitli on the Formation 



itself. The lines on it present no trace of organic structure, 

 but are obviously caused by the rapid revolution of the particles, 

 to which motion the flint, almost free from trace of organism, 

 probably owed its solidification. 



These facts are obviously totally incompatible with the sponge 

 theory. Not only is it clear that no sponge can ever have taken 

 such forms of growth as these, which are obviously the result of 

 mechanical causes acting, not on an animal substance but on an 

 inorganic one; but, while the sponge theory, necessarily assuming 

 as it does the decomposition of the saturated sponge, requires 

 as a necessary postulate a very slowly solidifying body, as the 

 only means of accounting for that decomposition, the facts above 

 named obviously point to a very rapidly solidifying substance, a 

 condition, too, best agreeing with known phsenomena. Nor do 

 the facts admit of that substance being of the nature suggested 

 by Dr. Buckland. They seem, on the contrary, necessarily to 

 indicate a substance which, while of a considerable specific gra- 

 vity (flint is 2*59), was in an extreme state of liquidity* for the 

 time, but liable to extremely rapid solidification ; in fact such a 

 substance as Dr. Turner indicates. The sharp edges, as well as 

 the character of the ridges, preclude the supposition of a viscid 

 fluid. Phsenomena analogous to those suggested as explanatory 

 of the condition of fig. 1 are often seen in cold weather in a 

 vessel of water in which fine flakes of ice only are seen while it 

 is at rest, but the moment it is agitated the whole becomes a 

 solid mass. Similar phsenomena may be produced experiment- 

 ally in many ways. 



The rare occurrence in the flint of instances like those just 

 stated probably arises from that very rapidity of solidification 

 which explains those particular instances ; a solidification which 

 contact with any organic body would equally induce, and which 

 would of course, therefore, prevent frequent liability while yet 

 liquid to such casualties as there happened. That rapidity of 

 solidification, — a fact, as has been seen, inadmissible on the 

 sponge theory, — is demonstrated not only by the facts last stated 

 but by those to be next named, and which, with the last, render 

 it indisputable that the flint was perfectly solid and brittle (and 

 not in anywise in the state of a glutinous or viscous mass) before 

 the chalk itself became solid or was in otherwise than the state 

 of a soft mud^ but yet while it was in a state of mud and not 



* Dr. Turner speaks, p. 27, of the silica being in a gelatinous form and 

 hardening slowly. Why this should ever have been assumed does not ap- 

 pear, and both parts of the assumption are obviously directly inconsistent 

 with all the general principles enunciated in that lecture and with observed 

 facts, as above shown. There is probably some incompleteness in this part 

 of the report of his lecture. » 



