162 J. C. WARD ON THE GLACIAL ORIGIN OF THE 



In the case of Red Tarn (fig. 18, PI. VII. B), immediately beneath 

 Helvellyii, scratched rock-surfaces may be seen passing beneath the 

 water at its upper end, while the banks at the lower seem made up 

 of morainic material. This tarn is very shallow and was dry in 

 1869 ; so that it is very likely that we have here merely a glaciated 

 hollow in the comb — between Swirral and Striding Edges — con- 

 verted into a lake by moraine-rubbish deposited at its lower end. 

 Keppelcove Tarn, a little further north, is also moraine-dammed ; but 

 whether wholly so or not, it is difficult to say* ; at any rate glacial 

 scratches may be seen on the rocky western sides. 



Stickle and Angle Tarns (figs. 21 and 20) are probably both rock- 

 basins of a slight depth converted into tarns of a greater depth by 

 moraines at the lower end ; and Blea Tarn, between Great and 

 Little Langdale, although now nearly filled up, may originally have 

 been a tolerably deep rock-basin, the mounds at its lower end, 

 which at first sight look like moraines, being rounded rocks with a 

 thin coating of moraine-matter. 



In all these cases it is clear, from the glaciated rock-surfaces, 

 that ice has occupied the hollows now filled by the tarns ; and it is 

 difficult to admit its scooping power in the case of very small rocky 

 basins and deny it in that of the larger, especially when it is 

 remembered that in many cases part, at any rate, of the depth, is ac- 

 counted for by the presence of moraines at the lower end. 



There are some instances, however, where no glacial markings 

 have been observed at the sides of a tarn, and yet at its lower end 

 there may be what appears like a conspicuous moraine. Of such is 

 Bowscale Tarn, two or three miles north of Blencathra (Saddleback). 

 It is possible that the Hornblende Slate, of which the tarn crags 

 are composed, has lost glacial markings originally impressed upon 

 it ; but at the same time the gathering-ground for a glacier is here 

 very small, and it is quite conceivable that the moraine-like mound 

 at the north side of the tarn represents the debris accumulated at 

 the foot of a snow-slope (fig. 19). The same may be the case in 

 some other instances of apparently moraine-dammed tarns. The 

 objection that is sometimes made to the glacial-erosion theory, 

 when applied to the case of tarns lying in combs, that there could 

 have been no feeding-ground for a glacier, is opposed by the fact 

 that ice-scratches, pointing directly out of the combs and often at 

 the head of the tarns, are frequently met with. The way also in 

 which these scratches occur, conforming in direction to the shape of 

 the comb, show that they must have been produced by small 

 glaciers originating in or occupying the hollow. Such tarns as Burn- 

 moor (31 feet deepf),Blea, Little Langdale, Elterwater (29 feet deepf ), 

 and Loughrigg (34 feet deep £), all lie in the direct paths of the main 

 glaciers, and, since most of them appear to be rock-basins, come 

 under the same head as the lakes before treated of. 



* Both these tarns have been converted into reservoirs, by means of artificial 

 dams and sluices, for the use of the G-reenside mine. 

 t Sounded by my colleague, Mr. Hebert. 

 } Sounded by my colleague, Mr. De Ranee. 



