KiNAHAx — On Sea-beaches. 199 



iudistinct, that no one unacquainted with such accumulations would 

 observe them ; but they are characteristic of the S. portion of the 

 strands of "VVicklow and Killiney Bays, always occurring in connexion 

 with the " counter-tides." They are best developed during directly 

 on-shore gales from the E. If formed during the rise of the spring 

 tides, each ridge after being produced is destroyed by the next " flow- 

 tide," but if formed during the fall of the springs, successive nearly 

 parallel ridges accumulate (Fig. 2, Plate 5), which remain till the next 

 spring, when they are levelled, and the material carried southward.^" 



It ought to be specially pointed out, that the storms which cut out 

 ■ the beaches may not he the same as those ichich denude away the marginal 

 cliffs. The beaches are principally "cutout" by "ground swells," 

 or storm waves, that come in an opposite, or obliquely opposite, direc- 

 tion to the "flow-tide" current, or they may be carried forward by 

 the sole agency of the tidal current, or by the latter assisted by wind 

 waves coming in a similar direction. Any of these causes may scoop 

 out or sweep a strand bare, and leave it with little or no beach ; and, 

 under the latter circumstances, the storm waves act with full force on 

 the marginal cliffs. ^^ A small storm when the strand is empty may 

 do great damage on the coast line ; while a great storm with a full 

 beach will do scarcely any. The best section of a beach seems to be 

 that similar to Fig. 1, Plate 5, having below, or to seaward, a slope (h), 

 above which is a flat or " cess" («, c), and higher up a second 

 slope (c), which is succeeded by a second " cess." Such beaches, how- 

 ever, seem to be of rare occurrence, they usually having cross sections 

 similar to that in Pig. Aa, PI. 6, with a slope below and a wido " cess" 

 above; but on the " cess" in this case the waves lose a great deal of 

 their power before they reach the marginal cliffs. 



Extraordinary high tides, unaccompanied with wind, seem to do 

 little or no damage on an open seaboard. In March, 1867, there was 

 a remarkably high tide on the coast of Gal way, the traces of which 

 were scarcely perceptible along the open coast, even on the sandhills ; 

 but in the land-locked bays it did considerable damage to the piers 



1" On tliis poi-tion of tlie Irisli shore, where there is a tidal cun-ent, the " storm 

 beaches ' ' only exist during the intervals between the spring tides ; but in other 

 places, where there is a "rise" and "fall" of tide, but no ciuTents, the " storm 

 beaches" remain, and add to the extent of the land. The latter is veiy well seen 

 in North Wales, along the coast line of Morecambe Bay, as also in other places. 



'1 After very wet seasons great falls of the cliffs often take place ; but until the 

 debris is denuded away, few or no further falls will take place. The natives will 

 often tell you that so many yards are going yearly, and in proof of this assei'tion 

 will point to the waste of the previous winter, they supposing that the same happens 

 every year. The greatest falls occur at the highest cliffs, on which account the 

 greatest waste is supposed to be taking place in these localities -, but after careful 

 calculation I find this not to be the case. None of the high cliffs reach an average 

 waste of -lb ft. per annum, and generally the loss is less than •') ft., while in 

 places the low cliffs have been denuded away as much as 2o feet per annum. The 

 greatest denudation on the whole line of coast between Hook and Dalkey is at the 

 low cUff near St. Patrick's Bridge, Kilmore. 



