8 Mr. Toulmiii Smitli on the Formation 



affinity for the silex than bone or shell ; through which latter 

 the silex would frequently pass without lodging there in order to 

 reach those parts for which its affinity was greater*. 



We now come to the innumerable cases in which organic re- 

 mains belonging to the many varieties commonly, though very 

 loosely, grouped as Ventriculites, whether cyathiform, flexuous 

 or quadrangular, and Choanites and the like are found imbedded 

 in flints ; and many of the most delicate of which we now find 

 imbedded in the solid flint with yet a light floating elegance of 

 form as if still enjoying life in their native liquid element ; and 

 which facts assure us that they were thus suddenly and instanta- 

 neously fixed in a moment of the highest vitality. 



What are the conclusions to which a careful and extensive ex- 

 amination of these objects necessarily leads ? 



First, that the animals were enveloped while living -^^ and not 

 after death, as the sponge theory assumes as a necessary postu- 

 late. The specimens are found both in flint and chalk in pre- 

 cisely the same conditions. They are found in all states, from the 

 fully expanded to the closely contracted. They are found — not, 

 as is the case with the sponge tissues, rarely or never, but — very 

 generally in a perfect state of preservation, the whole tissues and 

 structure being preserved to us in a condition fully as clear as if 

 the living being were before us. Now it is very easy to conceive 

 of the living animal being suddenly enveloped in a mass of soft 

 mud or other liquid which hardened more or less rapidly, but we 

 cannot conceive of its allowing the growth over it, w^hile living, 

 of a sponge w^hich enveloped without killing it or altering its ap- 

 pearance ; still less of that sponge afterwards decaying and leaving 

 the inclosed body undecayed. 



Second. It is beyond a question that the cause which gave 

 rise to these flints was not a foreign body enveloping the exterior 

 of the Ventriculites and other bodies, but a substance which pos- 

 sessed the quality of penetrating their most intimate structure. 

 It is only necessary to examine polished specimens of either 

 Choanites or the cyathiform, quadrangular or flexuous Ventri- 

 culites, or the specimens of either cracked open, when, as is often 

 the case, they admit of this, to be fully satisfied on this point. 

 The structure of these bodies themselves remains perfect and 

 most beautiful, while no enveloping structure or tissue can be 

 made out, except in the occasional fragments already noticed. 

 Again, it is not unfrequently found that the flint itself has only 



* The same point is well illustrated by cases of fish and Crustacea, of 

 both of which I have specimens of which the integument remains unsili- 

 cified, the interior is solid flint. 



f This might easily be shown to have been the case with other classes of 

 objects, but space forbids extending the illustrations. All these soft parts 

 are preserved, and yet the enveloping sponge has decayed ! 



