Wright and Muff — P re-glacial Raised Beach. 265 



from the cliffs and its low angle of slope preclude the idea of its 

 being ordinary screes. The materials seem to have been carried 

 out from the cliff ; and, on the whole, the finer materials have 

 been moved furthest. Periodical heavy rains washing down the 

 slopes might have effected this. 



Owing to the superposition of the boulder-clay, it is not easy 

 to perceive the form of the upper surface of the head. Though it 

 generally seems to rise towards hollows in the hills, there is hardly 

 sufficient evidence for stating that it accumulated as a series of 

 cones of dejection. It is, however, to be noticed that a large cone 

 of head, with its apex pointing up a valley, lies on the pre-glacial 

 shore-platform, just over two miles east of Ballycroneen. The 

 upper head also forms a small cone, resting on the boulder-clay 

 in the middle of Ballycroneen Bay. Its apex is directed up a 

 small valley in the pre-glacial cliff. 



In order that the head might accumulate, it is necessary for the 

 platform to have been raised beyond the reaoh of the waves. An 

 elevation of 10 or 20 feet above its present level would have been 

 sufficient to allow of this accumulation. 



There is difficulty in the way of making any definite deduc- 

 tions from the nature of the head as to what were the climatic 

 conditions at the time it was formed. It is fairly clear that it 

 indicates the action of frost, or of rapid alterations of temperature, 

 in shattering the rocks and forming screes, and of periodic heavy 

 rains in washing the material further from the cliff. It is hard to 

 say, however, whether the shattering action is that due to the expan- 

 sive force of water in a wet climate, or that due merely to rapid 

 and unequal expansion and contraction in an arid climate. The 

 first state, and indeed a condition equivalent to the second, might 

 arise as the result of a great elevation of which the 10 or 20 

 feet mentioned above may have been only the beginning. There 

 were, however, changes of climate in progress before the uplift 

 began, so that, although it must always be kept in mind as a 

 possible cause of the conditions, it is not at all a necessary nor 

 even a probable one. 



Other ways in which the required climatic conditions might 

 be brought about can be adduced. A general lowering of mean 

 temperature during part or the whole of the year might cause more 

 frequent frost-action without any other change in the climate. 



