AND RIVER VALLEYS BORDERING THE BRITISH ISLES. 317 



outer or " grand submerged escarpment " which finally descends 

 to the deeper oceanic or abyssal plain. 



The courses of the rivers Erne, Shannon, and the " Irish and 

 English Channel rivers'' of Dr. Hull, on the south and west of Ireland, 

 and between England and France, to the edge of the 1,500-fathom 

 or 9,000 feet contoui*, convey to us, through this paper, facts 

 hitherto unexpected. We are now able, through his analysis of the 

 soundings tvest of the 100-fathom plateau, to restore the "di'owned 

 valleys " of Western Britain and Europe, and may prolong the 

 deep soundings of the N^orth British coasts across the ISTorth 

 Atlantic to meet the line of soundings from North America in the 

 region of 52° iST. latitude, which rise northward to the Icelandic 

 ridge north of Rockall. 



Professor Hull's interpretation that the submerged, and now 

 submarine, valleys were originally formed or fashioned through 

 atmospheric denudation in the widest sense, prior to their sub- 

 mergence, is fully demonstrated in his paper, and by his accom- 

 panying map and sections, they are a clear exposition of the 

 arguments thei'ein adopted. The six bathymetrical sections, as 

 would be expected, demonstrate the depths, or amount of depres- 

 sion shown through the contour lines. The two canon valleys 

 ("the Irish Channel river" and the ''^English Channel river'" on 

 the Continental platform) reach the outer deep-sea escarpment at 

 the 250 and 270-fathom line, or 1,500 and 1,620 feet deep respec- 

 tively. The Shannon channel descended to the 250-fathom line, or 

 1,500 feet; that of the river Erne to the 750-fathom, or 1,620 feet 

 contour. We must congratulate Professor Hull on his affording 

 us much new information relative to the hydro-geographical and 

 probably hydro-geological research around the westerly extended 

 submerged land extending from the coasts of North Scotland, 

 Ireland, France, and on to Spain. 



Mr. D. Howard, F.C.S., D.L., &c. — Judging from the shallower 

 seas off the mouth of the Thames, and how pow^erful the silting-up- 

 process is there, the wonder is that the caiions should have re- 

 mained as they are. The instances given in the paper show how 

 rapidly the silting process may take place under favourable cir^ 

 cumstances. 



Professor J. Logan Lobley, F.G-.S. — We must all feel indebted 

 to Professor Hull for this important paper : it is not only a con- 

 tribution to geological, but to geographical, knowledge. 



Its chief value, geologically, is, perhaps, the aid it gives us in. 



