THE GLACIAL DEPOSITS OF WESTERN CARNARVONSHIRE. 



37 



beautiful examples of oblique bedding. The deposits in the western half of the section 

 are very varied, and change frequently in nature when traced laterally. Near Afon- 

 wen a bed of peat is seen under the soil and blown sand, and where the cliff descends 

 the peat comes down on to the beach. The well-bedded sands generally underlie the 

 coarse gravels. Inclusions or pockets of stiff yellow clay occur in the gravels. At some 

 places the pebbles or rounded boulders are heaped in a tumultuous fashion and show no 

 traces of bedding (fig. 5). A curious accumulation of well-bedded ferruginous sand 

 occurs at one place in the cliff, the beds being arched up (fig. 6). This may repre- 

 sent an intra-glacial channel which became filled up with sand arranged in beds. When 



Soil. 



Upper Boulder Clay 

 —10 feet. 



Coarse gravels with -ffi 



some sand — 18 feet. —' 



Fine-bedded sand. 



Sand, more clayey 

 at the bottom — 15 

 feet. 



Bedded sand. 

 Beach. 



10 feet = l inch. 

 Fig. 8. — Diagram of the Afonwen Section near the East End. 



the walls of ice disappeared the beds would tend to bend over at the sides so as to give 

 an archlike arrangement. These ferruginous beds are followed by boulder gravel and 

 over this lies stony till full of boulders which are glaciated. 



About midway along the section peat again appears. Two beds can be seen 

 separated by a thin band of very stiff bluish-grey clay with rootlets. The lower bed 

 of peat is underlain by tough bluish clay of a similar nature. This peat was examined 

 by Mr F. L. Lewis of Liverpool University. He states that it yielded : — Viola 

 palustris, Carex sp. (fragments), Menyanthes trifoliata seeds (fairly numerous), frag- 

 ments of Sphagnum leaves, Potamogeton fruits in fragments (most probably those 

 of P. natans), also scraps of birch bark and birch wood. Further east these beds 

 of peat seem to unite owing to the dying out of the intermediate band of stiff 



