Wkitaker — On Subaerial Denudation. 453 



having been sea-cliffs." Now, as will be noticed further on, needles 

 are formed by atmospheric actions at the top of high cliffs ; indeed, 

 in nearly all cases they are formed from above, by something that 

 acts downwards along lines of joint, or fissure ; and I can see no 

 reason why they should not be formed inland, under favourable 

 circumstances, as well as on the coast ; though of course the latter 

 is one of the most favourable parts for the weather to wear away 

 rocks, by reason of the carrying away of the debris by the sea. 

 Moreover the question of the formation of such inland needles in 

 France by subaerial actions has been worked out by M. Ch. Martins 

 in a paper noticed before. 



(10.) It is however needless to take up the argument in this 

 way; for before anyone calls forward witnesses of such doubtful 

 character to prove the marine denudation of a long winding valley 

 like that of the Seine, he is bound to show that the sea can make 

 such a valley, or to point to some place where it actually is doing 

 such work : just as those who say that the sea makes escarpments 

 are bound to show that it can and does do that sort of work now. 



I need hardly say that both these things are impossible. None of 

 the advocates of marine denudation have given the proofs and 

 examples needed ; and they never will, for the simple reason that 

 there are none to give. 



This is a matter of reasoning simply, not of scientific truth alone, 

 and it would be well if the rules of the former were a little more 

 heeded by those whose wish should be to reach the latter, as else 

 they stand little chance of getting at their object. One of my 

 colleagues, who is a strong believer in the sea, and nothing but the 

 sea, has gone so far as to say that "attempts at proving or dis- 

 proving the soundness of speculations on natural phenomena by a 

 logical syllogism are scarcely creditable to men of science."^ To such 

 a statement I must strongly object, for it is clear that the first thing 

 needed of an argument is that it should be logical. One should not 

 be surprised, however, at the advocates of the marine formation of 

 valleys and escarpments looking down on logic (as an unpleasant 

 test to apply to their arguments) and scorning syllogisms, or in 

 other words despising true reasoning, unless they follow and " over- 

 come those prejudices which contracted views of nature and magnified 

 opinions of the experience of man may have begotten, prejudices 

 that are apt to make us shut our eyes against the clearest light of 

 reason,"^ and give up one of the most illogical theories that the 

 ingenuity of geologists ever invented. 



(11.) Some folk begin by misrepresenting the followers of Hutton, 

 and then go on triumphantly to disprove the theory which they 

 have misunderstood, or sometimes I fear have not taken the trouble 

 to understand. Thus it has been said that the Huttonians (if that 

 old name may be used in the limited sense here meant) deny the 

 power of the sea, and say that rivers, glaciers, rain, and frost have 

 done everything. Now nothing could be further from the truth ; 



1 Geol. MAQt., Vol. III. p. 571. 

 2 Hutton, " Theory of the Earth," vol. ii. p. 367. 



