446 D. Mackintosh — Geology of the Lake- District. 



intercepted and collected falling screes, which of course would form 

 moraines. A part of the debris may have found its way through 

 cracks to the beds of the glaciers, and terminal moraines, resulting 

 from the shedding of supra-glacial detritus, may have become mixed 

 with protruded sub-glacial mud and stones. But the constantly- 

 encroaching sea, during the sinking of the land, must have re- 

 distributed the moraine matter (as Professor Kamsay has shown it 

 must have done in North Wales) to such an extent that it would 

 now be unreasonable to look for many instances of unmodified 

 glacial moraines in the lower valleys of the Lake District. The 

 existence of false-bedded sand and gravel up to at least 1,000 feet 

 above the present sea-level, {see sequel) shows that the country was 

 certainly submerged to that extent, and the mode of occurrence of 

 Boulder-clay at higher levels would seem to indicate a deeper sub- 

 mergence, so that very few unmodified moraines of the pre-marine 

 set of glaciers are probably now to be found. 



In the Lake District the true glacial moraines, consisting mainly 

 of ridges or banks of loose angular stones, are chiefly, though not 

 exclusively, to be seen in upland valleys and cwms, where they 

 were probably shed by small glaciers after the emergence of the 

 land. At low-levels the moraine-matter, along with matter detached 

 by the direct action of the sea, has been so rearranged that the 

 external form of the hillocks, knolls, and ridges, supposed by 

 many observers, at first sight, to be real glacial moraines, is 

 merely a continuation of the contour of the undulations which 

 diversify the surface of the drift-deposits in the valleys, on the 

 plains, and along the sea-coast. Where good sections are obtained, 

 many of the reputed moraines are found to consist of pinel, often 

 distinctly surmounted by loam, both of which are an inland and 

 upland extension of the general Boulder-clay of the N.W. of Eng- 

 land.^ From Troutbeck, Windermere, Kentmere, Ullswater, Borrow- 

 dale, Crummock, and other valleys, the alternating flat expanses, 

 and knolls and basins of drift, run out to great distances along the 

 neighbouring plains, where they ramify in various directions.^ 

 There is no difference in form between the plateaux and undulations 

 at the lower end of Troutbeck valley and those which cross the 

 watershed between Windermere and Kendal, and run along between 

 Kendal and Lancaster, while, in internal structure, the difference 

 (where any difference exists) is only what may have resulted from a 

 deep or shallow sea, flat or sloping ground, and a greater or less 

 share of ice-action in connection with that of water. 



The theory of a general ice-covering, with an ice-foot changing its 

 level upwards as the land went down beneath the sea (as ably 



1 Many, if not most of these mounds exist, because the drift of which they consist 

 ■was directly, or indirectly, arrested by a projecting boss of rock. 



2 The regularly flat or curvilinear surface of drift-deposits is owing partly to 

 deposition and partly to denudation. It could only have been left by the sea, as the 

 effect of rain is to rut down the sides of the knolls and break up the plateaux, while 

 rivers either make well-defined channels in the plateaux, or, by encroaching on the 

 knolls, convert their slopes into cliffs. 



