Dr. Ramsay on the Physical History of the Dee. 561 



author as the remains of considerable deposits which once occupied 

 large areas in the valleys of South Devon ; and if they are not the low- 

 land gravels of Mr. Belt, the latter are not represented in the district. 

 The author states that there is evidence of the contemporaneity of 

 these deposits with those of the Oreston caves ; and he adds that 

 they furnish no proof of cataclysm al action, but of orderly deposition, 

 the bulk of the pebbles and gravels being inland, nearer the source of 

 the debris, and further off the sands and clays, in fairly regular suc- 

 cession. The author further explains the presence in Cornwall of 

 stanniferous gravels only in valleys opening to the south, by refe- 

 rence to the position of the watershed in that county, which has only 

 two rivers running to the north, whilst on the south-east rivers 

 abound. 



April 26, 1876.— Prof. P. Martin Duncan, M.B., F.R.S., President, 

 in the Chair. 



1. A Translation of a Notice, by Capt. Miaulis of the Greek Royal 

 Navy, of the occurrence of a Submarine Crater within the Harbour 

 of Karavossera, in the Gulf of Arta. Communicated by the Secretary 

 of State for Foreign Affairs. 



2. " The Physical History of the Dee, Wales." By Prof. A. C. 

 Ramsay, LL.D., P.R.S., V.P.G.S. 



The author stated that he regarded the valley of the Dee as mainly 

 preglacial throughout, and sketched the physical history of the 

 region through which it runs. The Silurian rocks were much dis- 

 turbed and denuded before and during the Carboniferous period, and 

 the Carboniferous Limestone was deposited very unconformably on 

 the upturned edges of both Lower and Upper Silurian strata, and 

 once spread all over the region, probably overlain by the Millstone 

 grit and Coal-measures, as now in the east of Denbighshire and 

 Flintshire. The region was again disturbed and elevated during the 

 formation of the Permian deposits ; and then by subaerial denuda- 

 tion a great part of the Carboniferous series was removed down to 

 the old plain of denudation of the Silurian rocks, the surface of 

 which thus probably stood higher than it does at present, being in 

 the midst of a broad continental area. Prom a consideration of the 

 conditions of deposition of the Mesozoic and Tertiary formations the 

 author concluded that, from the beginning of the Permian to that of 

 the Glacial epoch, the higher ground of Wales was land well raised 

 above the sea, except perhaps during the deposition of the Chalk, 

 and that during all this period it was exposed to the influence of 

 subaerial agents of denudation. He indicated the conditions of ele- 

 vation of the old tableland of Carboniferous rocks, and showed 

 that it had probably a slope towards the east and north-east to the 

 extent of about 23 feet in a mile. The drainage of this land then 

 flowed in an easterly and north-easterly direction along the earliest 

 channel of the Dee, which would be at an elevation from 1300 to 

 1400 feet higher than the present channel. 



During the Glacial epoch ice-action deepened and more or less 

 modified the existing channel, and scooped out the basin of Bala 



Phil. Mag. S. 5. No. 7. Suppl. Vol. 1. 2 P 



