KiNAHAN — On Sea-beaches. 203 



••a similarly circumstancecl sandy strand at the west end of the Tacum- 

 shin ^olian sand ridges (Chart sheet, xi"v.), which was visited during 

 low water on April 4, 1876, after a heavy gale from the S.W. Sec- 

 tion (Plate 5, Pig. 3) represents the form of the beach. Below, at the 

 line of low water, there was nearly level, undisturbed fine sand ; next 

 above this was a slope of shingle, mixed with gravel and sand. At 

 A and B, above and below the shingle slope, were lines of blocks 

 with deep-seaweeds attached to them, and a few similar blocks were 

 scattered over the slope, while they were very numerous on the 

 nearly flat undisturbed sand, between B and C. As the tide rose, 

 the blocks to which seaweed was attached began to travel landwards, 

 although there was no wind, and only slight waves, due to a " ground 

 swell." When visited twenty-four hours afterwards, not a block 

 remained on the fine sand, and only a few on the shingle slope, 

 they having been collected into horizontal lines at A and B. Subse- 

 quently this beach, as also others similarly circumstanced, were visited 

 after storms, and in all cases the results were the same ; as the large 

 stones attached to deep- seaweeds were brought in, and in one or two 

 tides sorted and arranged in lines, below and above the slope of the 

 beach. 



"When discussing this subject with Mr. Thos. Winder, M.. Inst. 

 'C.E., he mentioned that after he had ran out the Dover Breakwater 

 into ten fathoms water, "pebbles, during storms, were carried round it, 

 foundations opened were filled with sand and gravel, the pebbles usu- 

 ally not being larger than nuts, but sometimes as large as hen eggs ; 

 while rounded chalk fiints, from the Shakespeare Cliff, were carried to 

 the end of the breakwater"; also that a piece of iron plant, about 1"5 

 feet by 2 feet, and 1-5 inches thick, was, during a gale, blown off the 

 stage, and carried about twenty feet to leeward, or about thirty feet 

 from the end of the work, in water about ten fathoms deep. " I traced 

 the track of it through the small thread-like seaweed, and my conclu- 

 sions, as I stood on the sea-bed, were that the sea undoubtedly moves 

 things which may fall upon, and stand above, the general sea-bed in 

 •depths of ten fathoms ; although it does not move the fine and tender 

 growth which my feet trod into the surface, and my hands easily 

 pulled out of it." 



During storms large stones, with deep-seaweed attached, are car- 

 ried up on to St. Patrick's Bridge, near Kilmore, county Wexford, 

 as also on to the tidal portion of the Long Bank off Ballygeary Bay. 

 At the Kish Bank, off Dublin Bay, an attempt was made to erect a 

 lighthouse on screw piles ; but it was given up, as the flanges of the 

 piles were broken by large blocks in the accumulation of sand. Such 

 blocks were probably carried by seaweed to this shoal, as the shifting- 

 nature of which shows that it is the result of the action of the present 

 sea, and not a submerged hill of boulder drift. 



From the foregoing observations it would appear that large blocks 

 can be drifted in considerable depths of water : not by the simple im- 

 pulse of the currents or storm waves, applied directly to them, but by 



