and on Boulders tramported by Floating Ice. 353 



of the appearances described, I have been enabled to make a 

 few additional observations. 



Dr Buckland has stated, that, a mile east of take Ogwyn, 

 there occurs a series of mounds, covered with hundreds of large 

 blocks of stone, which approach nearer to the condition of an 

 undisturbed moraine than any other mounds of detritus noticed 

 by him in North AVales. By ascending these mounds, it is, 

 indeed, easy to imagine that they formed the north-western 

 lateral moraine of a glacier, descending in a north-east line 

 from the Great Glyder mountain. But at the southern end of 

 Lake Idwell, the phenomena of moraines are presented, though 

 on a much smaller scale, with perfect distinctness. On entering 

 the wild amphitheatre in which Lake Idwell lies, some small, 

 conical, irregular little mounds, which might easily escape at- 

 tention, may be seen at the further end. The best preserved 

 mounds lie on the west side of the great, black, perpendicuhu: 

 face of rock forming the southern boundary of the lake. They 

 have been intersected in many places by streams, and they are 

 seen to consist of earth and detritus, with great blocks of rock 

 on their summits. They at first appear quite irregularly 

 grouped ; but to a person ascending any one of those furthest 

 from the precipice, they are at once seen to fall into three 

 (with traces of a fourth), narrow, straight, linear ridges. The 

 ridge nearest the precipice runs some way up the mountain ; 

 but the outer one is longer and more perfect, and forms a 

 trough with the mountain-side, from 10 to 15 feet deep. On 

 the eastern and opposite side of the head of the lake, corre- 

 sponding but less developed mounds of detritus may be seen 

 running a little way up the mountain. It is, I think, impos- 

 sible for any one who has read the description of the moraines 

 bordering the existing glaciers in the Alps, to stand on these 

 mounds, and for an instant to doubt that they are ancient mo- 

 raines; nor is it possible to conceive any other cause which 

 could have abruptly thrown up these long, narrow, steep 

 mounds of unstratified detritus against the mountain-sides. 

 The three or four linear ridges evidently mark the principrl 

 stages in the retreat of the glacier : the outer one is the longest, 

 and diverges most from the great wall of jock at the south end 

 of the lake. The inner lines distinctlv define the boundarv of 



