502 H. B. Muff^ W. B. Wright— Glacial Beach, Cork. 



The overlying deposits, where completely developed, exhibit the 

 following succession of strata : — 



5. Upper ' head.' 

 4. Boulder-clay. 

 3. Lower ' head.' 

 2. Blown sand. 



1. Eaised-beach shingle and blocks from cliff. 

 Eock platform. 



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

 character to those forming the cliffs 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 down 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 blocks, 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 the present coastline 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 first 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 further 

 seaward, having in section a somewhat lenticular shape. 



The sections are, of course, not always as complete as indicated 

 above. Sometimes one member is absent, sometimes another, 

 but the succession 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 beach prior to the deposition of the Boulder-cla3^ 



The prepondei'ance of the lower over the upper ' head ' is na 

 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 pi'esent day. On the 

 contrary, the occurrence of flints in the beach near Clonakilty points 



