250 Scientific Proceedings, Royal Dublin Society. 
XXXVII—ON THE ARKLOW BEACH AND RIVERS, 
By G. H. KINAHAN, m.r.1a., &c. PLATES 16, 17, anp 18. 
[Read June 16th, 1879.j 
IN connexion with the travelling of Beaches, places of no mean 
interest are the beaches north and south of the present mouth of 
the Ovoca River, county Wicklow, or as it is more generally 
known, Arklow Harbour. 
On the coast between Arklow and Mizen Heads the “ flow tide ” 
current runs northward drifting the beach with it, and this north- 
ward driftage of the beach with the land driftage of the sand in 
a similar direction are the causes of the Arklow Harbour, in spite 
of the great sums of money spent on it, not being as commodious 
a haven as had been expected. 
On account of the northward travelling of the beach the river 
mouth is also inclined to move northward ;* while from the ap- 
pearance of the ground it is evident that in olden time it extended 
as far north as the Seabank Cliff. In the olden times, however, 
it is. probable that the outlet shifted considerably, changing accord- 
ing to wind and tide, from one place to another between the present 
site and Seabank Cliffs. The reasons for this are easily explained. 
If the only agent acting on the beach was the “ flow tide ” current 
its movement would be more or less regular, faster during spring 
than neap tides, but forming an even beach ; for as the materials 
were carried north they would be replaced by more from the 
south. But the winds, have also, considerable influence ; their in- 
fluences have been fully discussed elsewhere,t but it is necessary to 
refer shortly to them here. Winds from the south and south-east 
more or less accelerate the travelling of the beach, and if they are 
extreme it travels so rapidly northward that “ fulls ” of the beach 
form at the north, while the south portion is left empty. Strong 
* The travelling of beaches has already been discussed in papers read before the Royal 
Trish Academy ; Institutions of Civil Engineers, England and Ireland; and the Geol. Soe. 
Lond.—Proceedings Roy. Irish Academy, 1878 and 1879 ; Tran. Inst. C.E. Lond., 1878 and 
1879; Tran. Inst. C.E. Dublin, 1878 and 1879 ; and Quart. Jour. Geol. Soc. Lond., 1877. 
} Proceedings Royal Irish Academy, 1879. 
