of the Flints of the Upper Chalk, -295 



be proved by me. It is quite impossible to be more explicit on the 

 point ; and it would be as correct to represent an author writing 

 in support of the animal nature of sponges to be an advocate of 

 their vegetable nature, as thus, and so very little to the point, to 

 misrepresent my language and argument. 



On page 260 I am said to suppose the existence of " many 

 minute currents," without any evidence of such supposition from 

 my paper, and in direct opposition to my expressions on page 13, 

 where I speak of the " rare occurrence" of the instances. 



The pointing out the erroneous representations given of my 

 language and views of course relieves me from the necessity of 

 noticing at any length the discussions raised by Mr. Bowerbank on 

 the points thus erroneously stated ; but the fact of such numerous 

 misrepresentations existing argues little for the soundness of the 

 opposing theory. 



2. Nothing is more important in questions of science, as well 

 as of law, than to keep the real question always in view, and not 

 to travel out of the record, and so raise what the lawyers call 

 false issues. By raising always one certain, single and material 

 issue only can the truth be got at. Raising false issues, though 

 very convenient when an argument cannot be answered, serves 

 only to — but at all times it does — obscure the truth and confuse 

 and mislead the reader. The present question is with the flints 

 of the upper chalk *. We have nothing now to do with the sili- 

 ceous masses and cherty nodules of either mountain limestone or 

 tertiary beds. So, every one being familiar with the fibrous ap- 

 pearance of agates, &c., and with the occurrence of undoubted 

 sponges in the chalk flints, any discussion on either of these is 

 merely leading us astray from the point, viz. a universally appli- 

 cable generalization as to the formation of the flints of the upper 

 chalk. 



It may be very interesting, in a natural history of recent 

 sponges, to inform us of all the modes in which they are found. 

 But, unless it can be shown that they are found in flint as they are 

 alleged on page 253 &c. to be found recent, it is wholly beside the 



* In all geological questions, notliing is more important than stratigra- 

 phical exactness. A recent instance of neglect of this has occurred which 

 will be a fertile source of error and vain theory. In the second volume of 

 the * Journal of the Geological Society ' is a description of a Pterodactyle, 

 alleged to be from the "upper chalk." Immediately after it appeared (Feb. 

 1846) I informed the author that this was incorrect, as no upper chalk what- 

 ever exists in the localities whence his specimens came. No correction has 

 however been made, and it has now gone forth to the whole scientific world, 

 with the authority and sanction of the Geological Society of London (p. viii. 

 of vol. ii. of the Journal), that Pterodactyle remains have been found in the 

 upper chalk, a statement fruitful of future theories, and which is without a 

 shadow of foundation. 



