Correspondence. 279 



It may therefore be worth while for me to appeal to the second 

 edition of my " Descriptions of Volcanos," published so long ago as 

 1848, as showing, that although in my earlier publications I had 

 been led by the authority of Professor Buckland to attribute the 

 formation of valleys to catastrophic action, such as the Noachian 

 Deluge, I had for many years abandoned that hypothesis. 



This circumstance might of itself have been considered a tacit 

 acknowledgment on my part of the value of Mr. Scrope's earlier 

 contributions to Geology, but I was glad of the opportunity afforded 

 by the publication of my recent paper " On the Antiquity of the Vol- 

 canos of Auvergne," of more distinctly recognizing the claims of the 

 author alluded to, to the merit of having been the first of our 

 countrymen who clearly pointed out the evidence afforded by the 

 valleys of that volcanic district, as to the erosive agency of rivers 

 continued during long periods of time. 



Charles Daubeny. 

 Oxford, May 5tli, 1866. 



THE LONGMYND AND ITS VALLEYS. 

 To the Editor of the Geological Magazine. 



Sir,— I have just read Mr, Mackintosh's paper in the April 

 number, as well as his letter in the May number of the Geological 

 Magazine. 



I am well acquainted with the Longmynd and its valleys, and I am 

 still of the same opinion that I formed more than twenty years ago, 

 as to the origin of those deep valleys, locally called " gutters." I feel 

 not the slightest doubt that they were cut by running brooks. I 

 know of no better locality to which I would refer for so good 

 an example, to show the result of long-continued wear by running 

 water, than the Longmynd with its deep valleys. If the brooks 

 that now run in these valleys have the power to furrow even their 

 bottoms, they require only time to cut down a thousand feet. I 

 believe that the action of the sea could in no way excavate those 

 valleys or any similar ones. 



I may add, that after many years of constant observation in the 

 field, on a subject I have always been particularly interested in, I 

 feel now convinced that an immense amount of denudation is due to 

 causes subaerial, and not to the action of the sea, 

 I am, Sir, yours truly, 



W. Talbot Aveline. 

 Geological Survey of Great Britain, 

 Eden Mount, Kendal, 7th May, 1866. 



A DENUDING AGENT. 

 To the Editor of the Geological Magazine, 



Sir, — I have all my life been a diligent explorer of little brooks, 

 in search, I must confess, of beauty rather than fossils. I have often 

 been struck with the steady, and by no means unsuccessful, co-oper- 



