September 1898] THE ESKERS IN IRELAND 173 
300 feet from the existing level. The old sea-margins are pointed 
to in proof of the depression—lines of beach, and notches cut into 
the hill-sides ; but, as will appear further on, such evidence is by 
no means conclusive of marine action. 
“The low country,” continues Jukes, “is largely covered by a 
widely-spread mass of drift, consisting of dark sandy boulder-clay, 
with pebbles and blocks, and occasional beds of sand and gravel, 
sometimes very regularly stratified.” In a footnote he adds :— 
“This seems to be the equivalent of the Scottish 77l, at least in 
its upper part.” The gravel, it may be remarked, extends through- 
out wide areas and to considerable depth, without any apparent 
mingling of clay, but consisting wholly, or almost so, of sand and 
pebbles, “The great majority of the pebbles are rounded fragments 
of Carboniferous Limestone, whence the deposit usually goes by the 
name of the limestone gravel. This deposit rests not only on the 
limestone but sweeps up on the flanks of the hills, both those that 
are made of the lower palaeozoic rocks and those formed of the 
Coal-measures. In each case the limestone gravel becomes largely 
mingled with detritus of the rocks of which the hills are made, and 
sometimes to such an extent that the local rocks assume a decided 
preponderance and occasionally compose almost the whole of the 
deposit.” 
That these superficial deposits were formed under the sea, Jukes 
entertains no doubt, just as Professor Ramsay holds that the drift of 
North Wales is of marine origin. Kinahan agrees with Jukes. The 
only ground, according to these able writers, for a contrary opinion 
is supplied by the unfossiliferous character of the deposits, But the 
circumstances would not be in favour of the preservation of shells 
(save those embedded in the limestone) in a mass of materials, which 
presumably have been subjected to much agitation and trituration. 
Against these, however, we have the very decided opinion of 
Dr James Geikie, as to the analogous order of things in Scot- 
land :—“It seems most reasonable to conclude that neither the 
water-worn and stratified drift, nor the loose angular debris, nor 
yet the erratics that le scattered over the low grounds of Scotland, 
give any indications of a former submergence of the land below the 
sea. The loose angular debris or moraine matter and erratics have 
been carried down and dropt over the terminal front of the ice- 
sheet, or have stranded upon the mountain-slope and hillside, or have 
been left lying in what once formed the bed of the old ice-sheet. 
The sand and gravel drifts have been produced by the 
action of water escaping from the melting ice-sheet which 
re-arranged the morainic debris, &¢., heaping it up in banks 
or spreading it out in undulating flats” (“The Great Ice Age,” 
p. 244 of 2nd Ed). 
