Correspondence — Mr. G. H. Kinahan. 333 



COEEESPOITDEUGB. 



JUKES ON RIVER VALLEYS, S. W. CORK. 



Sir, — In reply to Mr. A. J. Jukes-Browne's letter in the Geol. 

 Mag. for May, 1879, 1 would point out that the apparent discrepancy 

 between the statements in " Valleys and their Eelations, etc.," and 

 in the " Geology of Ireland," is easily explained. In the first, the 

 statement refers to the formation of valleys in any county and in 

 any kind of rocks ; while in the second, the statement refers solely 

 to the valleys of S. W. Cork. Such a general statement as the first 

 would not refer to a peculiar country like S. W. Cork, where the 

 Carboniferous slate rocks are as hard and are as capable of resisting 

 denudation as the Old Red Sandstone, while if Coal-measures once 

 existed in the synclinal troughs, they probably were also indurated 

 and similar to the rocks that form the hills immediately north of the 

 Black Water Valley aud hills elsewhere in South Ireland. 



Jukes distinctly states that the Carboniferous slate was once 

 covered by limestones, while subsequently he relies on the soft 

 nature of the limestone to expedite the formation of his valleys. 



I cannot exactly see why this theory has a claim to be called " well 

 considered." When put forward, it was founded on suppositions 

 that were then questioned, and which have since been shown to have 

 been too hastily arrived at. It also ignores all faults and dislocations 

 of strata in the different areas mentioned, while originally it totally 

 ignored ice-action. It was only an afterthought, to bridge over the 

 last, that the statement " a glacier is only a frozen river " was intro- 

 duced ; but this does not meet the objection, as the actions of moving 

 frozen and unfrozen waters are very different. 



I do not for a moment presume to say that in no place could rains 

 and rivers produce the effects described ; but as the theory was 

 founded in a country and on suppositions which were afterwards 

 found to be erroneous, I think I am justified in saying the general 

 theory " falls to the ground." G. H. Kinahan. 



Ferns, May 13, 1879. 



DEVON GEOLOGY. 



Sir, — From the Eev. H. H. Winwood's letter, Geol. Mag. May, 

 1879, it would appear that my statement casts a slur on the Devon- 

 shire Amateur Geologists; for this I am extremely sorry, as such 

 was never my intention, the remarks being intended solely to refer 

 to a paper which I believe has been given much more importance 

 to than it merits. I can assure Amateurs that I look on them with 

 great respect, and I sincerely wish there were more of them in 

 Ireland, as they are the only safeguard against the overwhelming 

 vagaries and egotism of the " Trained Geologists " ; and I would 

 have much more respect for them if sometimes they were more 

 independent, as they often allow their well-worked-out results to be 

 snuffed out by individuals whose only claim to be heard is that they 

 are officials. 



I regret I cannot accept my friend's hospitable challenge for 



