Correspondence. 87 



causes have been at this work for " ages," by tlie discovery of a sub- 

 terranean Eoman villa. But what are such floods and deposits as these 

 compared with those of the Nile, Ganges, Mississippi, or Niger ? It is 

 something, however, that X and the Emperor, ego et rex mens, are 

 now convinced that the late disastrous floods in France and England 

 were simply the effects of rain, as " the flood " was of yore. But 

 when my two illustrious pupUs and the " Correspondent " attempt to 

 remedy the effects of rain on rivers I recommend them to leave 

 woods out of their consideration. Our respected grandmothers always 

 " babbled " about them. — Your obedient servant, 



George Geeenwood, Colonel. 

 Bbookwood Pabk, Alresford, 

 December 18th, 1866. 



TEE DEVONIAN EOCKS OF DEVONSHIRE, ETC. 

 To the Editor of the Geological Magazine. 



Sir. — I do not wish to enter into a controversy on the Devonian 

 delusion ; I had rather let my own field work, and that of the Irish 

 branch of H. M's. Geological Survey, speak for itself. 



There are, however, some statements in Mr. Salter's letter, in your 

 last number, which might mislead persons if they were allowed to 

 pass without contradiction. 



There is no unconformability between any parts of the Old Eed 

 Sandstone, either in the south-west of Ireland, or in South Wales. 



The unconformability which Mr. Geikie and other of my colleagues 

 have shown to exist in Scotland, between beds that have hitherto 

 been called Old Bed Sandstone, is of itself sufficient to prove that 

 that term can only be retained provisionally for those groups till they 

 are more thoroughly distinguished, and some of them freshly named. 



In Ireland I adopted the local name of " Dingle beds " for the 

 mass of red rocks that rest in ajDparent conformity on the Upper 

 Silurian rocks, and are covered quite unconformably by the upper 

 part of the Old Bed Sandstone. 



It is by no means certain, that these " Dingle beds " appear 

 anywhere in Ireland, except in the Dingle promontory. 



To the south of Dingle Bay, there is not the slightest trace of any 

 unconformability in the Old Bed Sandstone. 



Some years ago I wished to know whether the dying away of the 

 Old Bed Sandstone in South Wales, from Herefordshire towards 

 Pembrokeshire, was accompanied by any break in the veins ; I 

 examined the whole country, from the neighbourhood of Llan- 

 deilofawr and Llandovery, by Brecknock and Abergavenny to 

 Pontypool, but could not detect any direct evidence of unconform- 

 ability between the top of the Upper Silurian, and the base of the 

 Carboniferous Limestone. 



In North Devon I believe it will be possible to trace a boundary 

 between the red rocks of Porlock, Minehead and Dunster, which are 

 genuine Old Bed Sandstone, and the grey slates, and variously coloured 

 grits, and slates containing marine fossils above them. 



