KixAHAN — On Sea-beaches. 197 



tlae driftage is westward. This forms a "full" {a, Fig. 1, PI. 5) on 

 the slope of the beach, and gives the beach a lower (i) and an upper 

 (c) slope, with a cess, as the Dutch engineers call it (a o), between ; 

 thus producing a section, of a form best calculated to break the force 

 of the waves in the succeeding two hours of the full tide, which prevents 

 the storm waves from having full effect on the coast line. Ordinarily, 

 however, this beach is much cut out, especially by " ground swells;" 

 and when the shores are empty, gales, whether from the S. "W"., S., or 

 S. E., have great effect. Consequently, during the last forty years, 

 the coast line between Lady's Island Lake and Kilmore has been con- 

 siderably denuded away, especially in the vicinity of St. Patrick's 

 Bridge. These beaches, during the continuous E. and N". E. winds of 

 the spring of 1876, changed from their ordinary gravel into "fulls" of 

 shingle. This must have been solely due to the " flow-tide" currents, 

 as for months no wind waves broke on the coast. 



On the east coast, between Greenore and Dalkey Island, as a 

 general rule the beaches are travelling north, and this is accelerated 

 by the south and south-east winds ; there are, however, long stretches 

 of beach swept by " counter-tides," at which places these winds gene- 

 rate " cutting-out tides." Although the most continuous winds are 

 those from the S. "W. and "W. S. W., yet they are not effective winds, 

 as they come across the land ; their only effects being those due to the 

 " ground swells " generated by them and the driftage seaward of the 

 ^olian sands, so prevalent on the east coast line of Ireland. The 

 winds that do the most damage on this coast are those from the S.W. ; 

 but the most continuous that effect the beaches are those from points 

 between E. and jST., and their results are perhaps the most interesting. 



The points of interest in the South or BaUygeary Bay, JN". "W. of 

 Greenore, will have to be mentioned hereafter when describing the 

 harbours and groynes, so at present they may be passed over. In the 

 J^orth Bay all winds seem to "cut out," this being due to the com- 

 plication of the tidal currents, the beaches rarely being full, except 

 in the summer and autumn, when there are no winds. On account of 

 the great cutting out along this beach, the marginal cliffs have been 

 vastly denuded within the last forty years. The " Cahore Shingle 

 Beach," at the north of the bay, is fullest during S. and S. E. gales; 

 while it is cut out by winds from the N. E. and by " ground swells." 

 After S. and S. "W. gales it is often smothered up with fine sand, 

 blown from the adjoining accumulations of ^olian drift. 



A little N. "W". of Cahore Point is Poulduff Pier, with the beaches 

 accumulated since it was erected, while farther northward are the 

 piers and other works at Courtown. These will be described hereafter ; 

 but it may now be mentioned that between Cahore and Xilmichael 

 Points the driftage is nearly altogether northward, and accelerated by 

 the S. and S. E. wind, while the IS", to E. winds cut out the strands. 



On the coast line S. (Fig. 4, PI. 6) and N. (Fig. 5, PL 6) of Kil- 

 michael Point there has been considerable denudation of the sandhills 

 since the Ordnance Survey was made (forty years) . In the first locality 



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