438 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 28, 



tion to consider in what directions currents may have flowed to trans- 

 port boulders. We have already seen that not until the submergence 

 exceeded 1500 feet could there have been any through passage be- 

 tween the southern and northern parts of the present lake-district, 

 except by the straits of Dunmail Raise. That a current passed 

 through these straits from north to south seems improbable, since 

 no boulders of the rocks of Skiddaw and Blencathra are found any- 

 where along the St. John's or Thirlmere valleys. If, however, a 

 current at one time ran through these straits from south to north, 

 we should not expect to find boulders of the Upper Silurians of the 

 southern part of the lake-district transported north of Dunmail Baise, 

 since there are scarcely any points due south of the straits where the 

 Upper Silurians attain the elevation of 1000 feet. Again, it is some- 

 what significant that no boulders of the Volcanic series have been 

 detected up the valley of the Glenderaterra, between Skiddaw and 

 Blencathra ; hence we can scarcely suppose that any current ran 

 through that gap from south to north, though many boulders of 

 granite and hornblende slate have travelled southwards, and then 

 principally westwards towards Bassenthwaite. 



Of course it is very difficult to say how much of this transport of 

 boulders has been due to floating and how much to glacier ice ; and 

 it is very probable that the directions of transport in the two cases 

 were to a great degree the same. Thus I should be inclined to con- 

 clude that, when the submergence had reached 1500 feet, there may 

 have been a current setting through the straits of Dunmail Eaise 

 from south to north, turning eastward on reaching the end of St. 

 John's Vale, though perhaps sending off a small branch westward 

 as well — also that a current may have set through the straits be- 

 tween Skiddaw and Blencathra from north to south, turning for the 

 most part westward on gaining the wide channel of Keswick Vale. 

 It is quite possible, however, that before the submergence had reached 

 1500 feet, and before the strait had been opened through between 

 Skiddaw and Blencathra, a main current passed through what is now 

 Keswick Vale from west to east, skirting also the whole district on 

 the west, across the end of the Vale of Lorton, and dispersing 

 the greenstone boulders from Sale Fell southwards to Broom Fell. 

 I fully trust that more extended observations to the north and east 

 of the area now described may either confirm or prove the incorrect- 

 ness of such surmises as to the directions of these old currents. 



3. Period of Local Glaciers and Re-elevation. — The non-occurrence 

 of true moraines over any part of the area occupied by the drift 

 gravel is, I think, sufficient evidence that there was no return of the 

 great ice-sbeet or even of very considerable glaciers after the land 

 had been re-elevated. All the main upland valleys, however, had 

 their glaciers during this later cold period ; and the fresh-looking 

 moraines now to be seen in them are the last relics of our Glacial 

 Period. 



In this paper I have been dealing solely with that part of the 

 district north of the great east and west watershed ; I may here add 

 that, so far as I have myself examined the country south of that line, 



