LAKE-BASINS OF CUMBERLAND AND WESTMORELAND. 161 



Easdale. It may seem strange to some, on the glacial- erosion 

 theory, that Easdale under a moderate thickness of ice should be as 

 deep as Grasmere or Derwentwater under a much greater thickness. 

 But we should always consider the nature of the ground in every 

 case. Thus, in that of Easdale we might have the scooping power 

 exercised just at the foot of a very considerable fall (see fig. 12), 

 while in the case of Grasmere the warn mass of ice would be moving 

 down a valley of very gentle slope ; and it might be that when some 

 obstacle, such as Loughrigg Fell (65), was opposed to its onward 

 path, then the deepest hollow was excavated. Certainly, if we are 

 to admit that the other lake-basins already treated of were formed by 

 glacial erosion, there is no difficulty in including such tarns as Codale 

 and Easdale, and such lakes as Grasmere, under the same head. 



c. Langdale Old Lake. — It seems highly probable that there 

 formerly existed a long lake in Great Langdale, now represented by 

 a stretch of alluvial land, which is not unfrequently much flooded. 

 Fig. 15, PI. VII. B, is a section of the head of this valley, where 

 Mickleden and Oxendale unite ; and in fig. 14 the form of the valley 

 is again seen near the termination of the lake at Chapel Stile. 

 Mention has already been made of the volume of ice which flowed 

 down the dale, and which, on the theory of glacial erosion, may have 

 been instrumental in the formation of this old lake, since filled up by 

 material brought down from the head and steep sides of the valley. 



d. Various Tarns. — It is not easy to determine certainly whether 

 a tarn be moraine-dammed or whether it be a true rock-basin, 

 unless its depth is known and the probable thickness of the morainic 

 material. Thus, at first sight, Easdale Tarn might appear to belong 

 to the former group ; but when its depth is known, and that depth 

 compared with the height at which rock is seen below the moraine- 

 material, it may be confidently classed with the true rock-basins. 



There is every transition from the merest rock-bound pool, with 

 glaciated inner surface, to tarns of considerable size, down beneath 

 the waters of which the ice-scratches may be seen to run, and 

 which are bounded at their lower ends either by a rounded rocky 

 rim, by the same with a thin covering of moraine-material, or by 

 undoubted moraines, which extend below the level of the water. 

 So that a tarn may owe its existence to a basin-like hollow formed 

 in the solid rock — to a somewhat similar hollow not wholly sur- 

 rounded by a rocky rim, but having the open end dammed by 

 morainic or similar matter — and to a combination of these two, in 

 which case a certain depth of water may be retained by a continuous 

 rocky rim, and the remaining depth by a moraine dam. In any 

 part of the district which is much glaciated — or, rather, in which the 

 effects of glaciation are well preserved — there may be seen many 

 examples of tiny ice-worn rock-basins. Just below and south of 

 Nethermost Pike, Hellvellyn(6)*, inRuthwaite Cove, is Hard Tarn, 

 150 feet by less than 100 in size it is very shallow, so that one 

 can see the rocky nature of its bed and sides, and mark how the 

 ice-scratches pass beneath the water from one side to the other. 

 * See Map in first paper. 



