252 Scientific Proceedings, Royal Dublin Society. 
such permanent outlet must have been made, as in 1835, at the 
time of the Ordnance Survey, the main channel oceupied nearly the 
pvesent position, but it was more or less shoaled, rarely over 4 feet 
in depth, while there was a second channel to the north of the 
present Chemical works, and farther north there were passages 
through the sand-hills covered at very high tides. On the map 
(Plate 18) the margins of the sea and the estuary are marked in 
black, while the new works and present marginsare indicated in red. 
On examining this map it will be seen the old sea margin was much 
more regular than the present one, and that since the present piers 
‘have been erected, the south beach has considerably increased 
while the land to the north has been encroached on. A remark- 
able feature in the 1835 map is a channel outside the sand-hills 
but separated from the sea by a shoal bank, that extends north- 
ward to the Seabank Cliff. 
In 1847 the first early permanent improvement was made in 
the erection of two quays with parallel north and south piers. 
During their erection it was found that, as long as the south pier 
was carried straight out, the strand followed it ; while during 
storms a shoal collected to the north of it. - It was also found 
that the wind driftage, due to gales from the southward, swept 
a vast amount of sand into the river, to be carried down to 
auginent the bar.* About the year 1860 under Barton the piers 
were extended further seaward, they being curved northward, 
following the trend the river course seemed inclined to follow ; the 
entrance was also narrowed to cause a sweep alongside the south 
pier, and thus prevent a shoal accumulating on the north of it. 
Also, the amount and current of the water in the estuary 
were increased, thus generating a greater scour on the bar, 
This was accomplished by extending the poundage room in the 
estuary, by deepening the river’s channel, and by regulating the 
latter by systems of “ piling, interwoven by watling.” Further- 
more, it was proposed to stop the northward travelling of the 
beach by groynes, and thewind driftage, from the 8., by a palisade, 
“a line of timber piles driven by hand and woven between with 
wattles.” Neither the groynes or the palisade were erected, but 
* During the erection of the south pier a bank of sand of about 500 tons was carted 
away for filling stuff, and this bank was filled in again during a twenty-four hour gale 
from the southward. 
