Rev. J. Clifton Ward — Geology of the Lake District. 113 



skirts of the district, carried boulders from Sale Fell southwards on 

 to Broom Fell. Not until the submergence reached over 1,500 feet 

 was there any direct communication between the northern and 

 southern halves of the Lake District, except by the straits of Dunmail 

 Eaise. Under such conditions a current very probably ran through 

 those straits from south to north, turning mainly to the east on 

 reaching Keswick Vale, though probably sending a branch off to the 

 west ; while other currents may have set through the straits between 

 Skiddaw and Blencathra. The case mentioned of an ash boulder at 

 the upper sources of the Caldew Avould seem to point to a current 

 having at one time passed from south to north, up the Glenderaterra 

 Valley and down through that of the Caldew. The block could not 

 have reached its present situation from any of the volcanic deposits 

 lying north of Carrock and Comb Height, and is scarcely likely to 

 have come from the very limited ash exposures of Eycott Hill, to 

 the south-east of the Caldew at Mosedale. It is not likely that this 

 boulder could have been transported by glacier-ice or any form of 

 ice-sheet, because it is in the very midst of lofty mountains which 

 would have produced sufficient ice to have filled the valleys between 

 them and kept out any ice-sheet foreign to this group. Hence, I am 

 inclined to consider this case as a proof of submergence to the height 

 of at least 1,300 feet, and of the existence of marine currents passing 

 through the Skiddaw mountain group. 



" The submergence continued until the land must have sunk more 

 than 2,000 feet below its present level, as the position of boulders 

 in many parts of the district seem to show, and notably those on 

 Starling Dodd (see page 93, also Quart. Journ. Geol. Soc. vol. xxix. 

 p. 437, and vol. xxx. p. 96). Then the whole district was repre- 

 sented merely by scattered islands clad in snow and ice, each a little 

 nursery of icebergs. 



" As the land was re-elevated, the glaciers crept down to the level 

 of the sea, sometimes forming moraines just at the sea-margin, as 

 was the case beneath Wolf Crag, Matterdale Common, when the 

 land stood 1,400 feet below its present level. During all this time 

 numerous boulders were let fall upon the early-formed mounds of 

 sand and gravel, and as the sea shallowed, more of such mounds were 

 deposited, now, however, frequently containing ice-borne blocks. 



" Finally, when the land had regained its former height above the 

 sea, glaciers still lingered in the recesses of the mountains, but this 

 second set of glaciers at no time equalled the first in size. Some, in 

 Borrowdale, were sufficiently large to creep down probably as far as 

 Bosthwaite, and the more or less perfect moraines in every upland 

 valley remain as the last traces of the Glacial Period. 



"I think too that the immediate cause of the numerous lake- 

 hollows, many of which are now completely filled with stream- 

 borne detritus, was the onward movement of the glacier-ice when at 

 its thickest, as suggested by Professor Bamsay's theory ; for not 

 only are these lake-basins extremely shallow when compared with 

 the heights of the mountains and the thickness of the former ice- 

 sheet, but in most cases the agreement is remarkable between the 



DECADE II. — VOL. VI. — NO. III. 8 



