1824.] Prof. Henslow's Reply to Dr. Berger. 407 



Article III. 



Remarks upoti Dr. Berger's Reply. By Prof. Henslow. 



(To the Editor of the Annals of Philosophy.) 



SIR, Cambridge, May 5, 1824. 



I felt somewhat surprised yesterday in perusing an angry 

 article in your number of the Annals of Philosophy just pub- 

 lished (for May), entitled, " Reply to Mr. Henslow's Observa- 

 tions on Dr. Berger's Account of the Isle of Man." 



The examination which I made (in 1819) of the geological 

 features of that island, was undertaken with a view of deriving 

 instruction, rather than with any intention of giving it ; as the 

 study of geology was then almost new to me. I, therefore, pro- 

 cured Dr. Berger's paper; and here acknowledge myself indebted 

 to it for almost the first rudiments of a science, which has since 

 afforded me so much gratification. As I had observed a few 

 omissions in that gentleman's description, as well as some errors 

 with respect to the extent of certain formations laid down in his 

 map, I presented my account to the Geological Society (together 

 with a collection of specimens to which my remarks might be 

 referred), by way of supplement to Dr. B.'s paper. From the 

 " Reply," it should seem that I had been misinformed, in suppos- 

 ing his account was not to be viewed as so perfect a perform- 

 ance as he now professes to have considered it himself. It was 

 under this impression that I troubled the Society with my 

 remarks. 1 might, perhaps, have written to Dr. Berger (as he 

 is pleased to suggest) had I been acquainted with his address ; 

 but I verily believed him to be no longer in existence. 



So far as I can collect from Dr. B.'s " Reply," his observa- 

 tions, accusations, and concessions, may be reduced to the 

 eleven following heads. Upon the fourth, fifth, eighth, and 

 tenth of these, I shall offer a few remarks ; the others appear 

 unworthy of any comment. The charges, then, here brought 

 against me, I consider to be, 



1. The correction of an error in the geographical position 

 assigned to the mountains of the south part of the island. 



2. The mention of a granitic district unnoticed by Dr. Berger. 



3. The extension of the limits assigned to a small patch of 

 granite noticed in his paper. 



4. The union of the slates under one common formation, 

 instead of retaining them under the boundaries assigned by Dr. 

 Berger to clayslate and greywacke. 



To this I may observe, that the distinctions of mineral cha- 

 racter, to which he refers, have long since been regarded (in this 

 country at least) as an insufficient guide to a difference of epoch 



