n 



m °rak 



eat rock 

 rtly damj 

 fes above 



arted froi 



It STONES 



rHED AM 



(unsifted' 



ne 



matter 



wynant. 



ELSPATtfJ 



a* 





.gula* 



,itio» > 



V*C& 



tb^ 



NORTH WALES. 



19 



an >Sno% °f the rock, and stretches across the hollow between two 



brooks, looking almost like an artificial mound, so perfect 



o 



f tbe . l 



Upper 

 Gallery, 



is its form. 



Many other traces of moraines occur higher i T ^ >le " cas ^ ] 



in this valley, especially in the neighbourhood of the little 



A.VEL urn lakes i n the uppermost recesses of Cwm Glas. 



Lhjda% 



75. — Mor 



roche moutonnee, 

 Llanberis. 



MUD AND SMALL ANGULAR STONES, m 



from the outer moraine, N. W. of the great 

 Blaen-y-Pennant, Cwm Glas, Pass of 



76. — Felspathic and slaty scratched angular stones, 



from the same moraine as 75. 



This moraine is elliptical in form, very stony, and divided 

 into two or perhaps three mounds, one within another, show- 

 ing, like the moraines of the glacier of the Rhone, the gradual 

 retreat of the glacier. In the same neighbourhood, between 

 Blaen-y-Pennant and Pont-y-Gromlech, on the S.W. side of 

 the Pass, at a short distance from the road, there is an immense 



than LIji mound of moraine debris, so lofty and solid looking that it 

 y poliste forms an actual hill. This is probably the remains of a 



great moraine shed by the Cwm Glas glacier, when it was 

 )yli, belotf at that stage that it descended into the Pass, and its ex- 

 alley 8^ tremity abutted on the opposing slope of Y-Glyder-fawr. In 

 f glacifl such a case, the debris that fell from the glacier on the side 



Pass 



that side of the glacier, while the moraine matter shed from 

 the side that looked down the Pass would in great part be 

 destroyed, nearly as fast as it was formed, by water flow- 

 ing from the glacier. Since the disappearance of the ice, 

 Qf jtf frf P art °f the great moraine has been entirely destroyed by 



the ordinary drainage of the upper part of the Pass of 



Llanberis. 



Moraine drift. — On the mountains of Caernarvonshire, 

 and in North Wales generally, the surface is, over large areas, 

 more or less covered by glacial drift. This drift rises from 



