Glaciers of North Wales. 407 



either flank of Aran Mowddwy. Further west, swelled 

 by all the snows of the Manods and the Moelwyns, a 

 great ice-stream flowed south-west, into what is now 

 the broad flat of Traeth Bach, there to be joined by 

 another tributary which, partly descending Cwm Llydaw 

 and Cwm-llan from the high eastern slopes of Snowdon, 

 rilled Nant Grwynant, and debouched into the area now 

 occupied by the marshy flat of Traeth Mawr. In all of 

 these the directions of the striations necessarily conform 

 to the trend of the valleys easterly, southerly, or 

 south-west, as the case may be. And this must have 

 been the case even though it happened that the moun- 

 tain valleys and broader amphitheatres were tilled to 

 the very brim, and overflowing with ice and snow in 

 such a manner that, had there been human eyes to 

 look on the scene, it would have been impossible to 

 have specialised each individual glacier. In such a 

 case, however, there were many deviations consequent 

 on under and upper ice-currents, the upper parts of 

 glaciers diverging from the direction of the under-flovv, 

 and passing across what are now low watersheds, like 

 that of Llyn Cawlyd, which lies between the valley of 

 the Llugwy, arid that of the Conwy a circumstance 

 to which special attention has been called by the Rev. 

 W. T. Kingsley. 



On the north-west slopes of the Snowdonian range, 1 

 great glaciers poured their ice-streams down the val- 

 leys of Llyniau Nant-y-llef to the west, and of Llyn 

 Cwellyn, Llanberis, and Nant-ffrancon, the last deriving 

 additional power by aid of the tributary ice-flows of 

 Cwm-llafar and Afon-gaseg, the chief gathering grounds 



1 I use the word range as a convenient term. There is no 

 range of mountains in North Wale's. Taken collectively they form 

 a group. 



