302 Mr. Toulmin Smith on the Formation 



found beyond the margin of the flint, as is the case in number- 

 less instances in true sponges. But it is continually found 

 that as well Ventriculites as sponges of many different varieties 

 are preserved in the chalk equally as in the flint, and that 

 without any connexion whatever with Ventriculites, but always 

 themselves again invested with the assumed parasites. It is 

 further to be noted, that there is not a single case in which a 

 Ventriculite or sponge is found silicified in a normal form, i. e. 

 without an assumed parasite ; nor, further, a single case in which 

 either Ventriculite or sponge is found inside the assumed para- 

 site in the unsilicified state in which each is so often found in the 

 chalk, and with the body or extended threads of the assumed 

 investing parasite alone silicified. What an extraordinary tissue of 

 contradictions is then involved in this theory ! Had such para- 

 sites existed, no one can doubt that they would have been often 

 found investing Ventriculites and sponges in the chalk and unsi- 

 licified ; and, further, that Ventriculites and sponges would have 

 been found silicified indifferently with or without parasites, as 

 well as unsilicified within the silicified parasite. The doctrine 

 of chances, which is but another name for the laws of unity and 

 design and the principles of induction, is at an end, if, to prop up 

 a theory, we are called upon to accede to postulates thus mon- 

 strous and contradictory, but absolutely necessary if the sponge 

 theory is to be sustained. 



I have alluded in my former paper to the frequent flint nodules 

 formed round the roots of Ventriculites. To my no small sur- 

 prise Mr. Bowerbank showed me a specimen of this kind, re- 

 moved at the lower part from the chalk ; and pointed to the 

 orifices through which the roots passed as proof that it had been 

 disrupted, and as great excurrent canals. I expressed my asto- 

 nishment as strongly as courtesy would permit. I stated that 

 I would engage that the assumed excurrent canals would, if cut 

 open, show roots of Ventriculites. Mr. Bowerbank, however, 

 insisted on the excurrent canals. Now, having hundreds of like 

 specimens in every condition, the true facts are so familiar to me, 

 that I can only be amazed at this as an extreme instance of the 

 lengths to which '^ anticipation" will lead a man to overlook the 

 most obvious facts in support of his theory. Mr. Bowerbank, 

 moreover, insisted to me that, where flints were formed round 

 roots of Ventriculites, the latter must have been disrupted and 

 lying on their sides ; remarking that it must be so, because other- 

 wise the sponge could not have grown round the roots, which, 

 normally, struck into the mud. This is indeed arguing in a 

 circle. I admit the latter part of the position, namely that no 

 parasitic sponge could have grown into the mud and so invested 

 the roots ; and, because it is so, I again assert that these flint 



