THE 



EDINBURGH NEW 



PHILOSOPHICAL JOURNAL, 



Indications of Glacial Action in North Wales. By Sir 

 Walter C. Trevelyan. In a Letter addressed to Pro- 

 fessor Jameson. 



Wallington, Morpeth, 14eA July 1853. 



My dear Sir, — Several years ago, when in North Wales, 

 I made notes of several indications I observed of glacial ac- 

 tion ; and as some of them have not, I think, been noticed by 

 other observers, I send yon a copy of some of the notes I made 

 at the time (in September and October 1844), thinking that, 

 if you should consider them worth a place in your Journal, 

 they may interest some of your readers, and draw attention to 

 localities which would, I think, repay further examination. 



On Snowdon, on the west side of the small lake at the foot 

 of the bold precipice of Clogwyn dur Arddu, is an enormous 

 moraine of large angular fragments, derived from the peak 

 from which it is separated by the lake ; its position can only 

 be accounted for by the deep interval having been filled with 

 ice, over the surface of which the fragments of rock had fallen. 

 Some of the rocks at the base of the peak above the lake, and 

 by the side of the stream by which its waters escape, have 

 been rounded and scratched by the action of ice. 



In Cwm Llan, at the eastern foot of Snowdon, is a terminal 

 moraine, the last probably left there by the melting glacier ; 

 it stretches across the termination of the Cwm in a semi- 

 circular form, and incloses several acres. The exterior slope 

 is about double the height of the interior, probably owing to 



VOL. LV. NO. CX. — OCTOBER 1853. N 



