658 REPORT— 1903. 



varying width, sloping gently seaward and terminated at its landward side by a 

 rocky clift" against which the deposits overlying the beach are banked. The 

 higher portions of this platform, just at the foot of the cliff, are from tive to ten 

 feet above high-water mark — that is, perhaps seven to twelve feet above the 

 higher portions of the corresponding plane of erosion in process of formation at the 

 present day. 



The overlying deposits, where completely developed, exhibit the following 

 succession of strata : — 



5. Upper 'head.' 

 4. Boulder-clay. 



0. Lower ' head.' 

 2. Blown sand. 



1 . Raised-beach shingle and blocks from clifF. 

 Rock platform. 



The ' head ' is composed of angular fragments of rocks similar in cliaracter to 

 those forming the cliti's above. It has a bedded appearance, like that of a tip-heap, 

 but there is no sorting of material. By far the greater proportion of it lies below 

 the boulder-clay. The upper ' head ' often contains rounded stones derived from 

 the drift. 



The boulder-clay contains well-scratched subangular stones, all local, but much 

 more miscellaneous than those in the 'head.' 



The blown sand is found banked against the cliff behind the ' head,' which has 

 the appearance of having slipped dovs'n little by little over it. The rock cliff" often 

 has a polished appearance, probably due to the action of the wind-borne sand. 



The shingle lies upon the platform among the bloclrs, which have evidently 

 fallen from the cliff above. The blown sand is heaped over and among these 

 blocks, which are absent in sections further from the old cliff. The shingle in 

 these seaward sections is often replaced by fine stratified beach-sand. 



As tlie present coast-line recedes from the old cliff', the ' head,' both upper and 

 lower, is seen to thin out and finally disappear. The boulder-clay, on the other 

 hand, thickens at tirst to seaward, until it replaces the * head ' and comes to lie 

 directly on the rock platform, which is often beautifully glaciated beneath it. 

 When sufficiently preserved, however, it can be seen to thin out iurther seaward, 

 Laving in section a somewhat lenticular shape. 



The sections are, of course, not always as complete as indicated above. Some- 

 times one member is absent, sometimes another, but the relative succes.sion is 

 invariable. With the exception of a few fragmentary shells no fossils have up to 

 the present been found in any of the deposits. 



The superposition of the boulder-clay and the glaciation of the rock platform 

 are taken to prove the preglacial — or, more strictly, the pre-boulder-clay — age of 

 the beach. 



The occurrence of blown sand and lower ' head ' indicates an elevation of the 

 beacli prior to the deposition of the boulder-clay. 



The preponderance of the lower over the upper ' head ' is no doubt due to the 

 greater steepness in preglacial times of the dominating cliff or slope from which 

 the 'head' was derived. It is as a consequence not to be taken as any indication 

 of a longer lapse of time between the elevation of the beach and the period of 

 glaciation than between that period and the present day. On the contrary, 

 the occurrence of ffints in the beach near Clonaldlty points to the presence of 

 floating ice during its formation, and indicates a beginning of glacial conditions 

 even before the commencement of the elevation. 



In Ballycroneen Bay a section of more than usual interest is exposed. The 

 ' head,' which here rests immediately on the rock-ledge, is overlain by two distinct 

 boulder-clays. The lower of these contains shell-fragments, chalk flints, and 

 boulders of Wexford and Waterford rocks, and is obviously the boulder-clay of 

 the Irish Sea Ice. The upper is the ordinary local boulder-clay of the district 

 laid down by the ice which moved from west to east over Cork. The beach is 

 therefore prior to both these ice-flows. 



