278 Scientific Proceedings, Royal Dublin Society. 



exposures of the beach-gravel and sand overlain by head. Some- 

 times the junction between the two deposits is sharp, but the 

 upper part of the gravel frequently contains angular fragments of 

 slate, either scattered through it, or more or less arranged in 

 layers, so that the line of separation is difficult to draw. 



East of Ballinglanna Cove, yellowish boulder-clay, 10 to 12 feet 



thick, overlies the rocks, and is covered by a varying thickness of 



upper head. The shore-platform of the small bay, one-third of a 



mile to the south-east, is cut in a series of vertical black slates to a 



very smooth surface, which slopes gently upwards from low-tide 



mark to the foot of the cliffs. The slates extend up into the cliffs 



for 10 feet, at which height they are abruptly truncated by a 



similar seaward- sloping surface, and are overlaid by about 12 feet 



of gravel. The gravel is cemented by iron-oxides, and consists of 



well-rolled pebbles with a good proportion of vein-quartz and hard 



grits. Yellowish- grey boulder-clay, from 12 to 15 feet thick, 



caps the cliffs. The pre-glacial cliff is close behind the present 



cliff at the centre of the bay ; but when traced eastward, it 



gradually recedes inland from the modern cliff. Consequently, at 



the eastern end of the bay, the truncated edge of the pre-glacial 



platform, being further from the pre-glacial cliff, is a few feet 



lower, and the base of the drift almost reaches high-water mark. 



At this point there are several stacks on the shore which are 



planed off at the top, and continue the slope of the old platform 



seawards (see Plate XXIX.). 



For some distance to the east, the seaward portion of the pre- 

 glacial platform forms the modern shore, and the cliffs consist 

 of boulder-clay overlying the cemented gravel. Two or three 

 outlying patches of gravel remain cemented on to the rock- 

 platform several yards from the cliffs. The pebbles in the 

 gravel are composed chiefly of the local green grits and of vein 

 quartz, but several well- rolled pebbles of flint, about half an inch 

 long, were also found in it. The boulder-clay is a stiff yellowish- 

 grey clay, containing numerous local grits and slates, and some 

 pebbles of Old Red Sandstone. Most of the stones are sub-angular, 

 but they vary from angular to rounded. Probably some of the 

 rounded ones have been derived from the underlying gravel. The 

 stones are seldom more than 8 inches long, and many of them are 

 well striated. 



