250 NATURAL SCIENCE [October 
I have described, and to the depth of twenty-five feet, without any 
indication of peat. The boring passed through beds similar to those 
of the ridge, but horizontal, and of closer grain. No boulders were 
met with until the water-bearing stratum had been tapped, and then 
some large ones were encountered. 
In the sand-hill group, the few openings I have seen showed 
less of the stratified arrangement, with a greater number of rounded 
pebbles, exemplifying, I think, the passage of the true esker into 
the morainic mounds, much acted upon by denudation. 
Are we then to take it as a settled matter that the esker sea is 
all a myth ? 
I hardly think so. Even Geikie admits the probability of an 
epoch of depression, and mentions that “gravel beds with marine 
shells have been traced in Ireland up to a height of 1235 feet on 
Montpelier Hill.” Again, how are we to account for the presence 
of large blocks of the red porphyritic granite of western Galway on 
the Sheve Bloom mountains? This granite, as Jukes remarks, ‘‘is 
easily recognisable inasmuch as it contains hornblende instead of 
mica, and has large crystals of pinkish felspar, and is therefore 
porphyritic.” How could these erratics be borne to their present 
situation except on rafts of floating ice? It is known that blocks 
of stone will sometimes rise through the glacier to its surface. 
But in such cases the erratics do not rise above the level of their 
origin; they merely describe a plane of less incline than the upper 
surface of the glacier. It may be contended that the period of 
depression did not synchronize with the formation of the eskers, 
and if so, we have new difficulties to meet. It may be that the 
eskers were not all formed at one time or in one way, and that 
most of the theories apply to a certain extent, while no one theory 
yet propounded, is comprehensive enough to cover all the ground, or 
clear enough to explain all the circumstances. I have no intention 
and no ambition to attempt a new solution. But I have frequently 
been struck by what appears to me the marked resemblance between 
some eskers and certain phenomena in progress round the shores of 
Galway Bay. 
In his essay on ‘“‘ The Arenaceous Rocks of Ireland” (Proe. R. Soe. 
Dublin, n.s., vol. v., p. 507, 1887), Kinahan describes a curious spit 
of conglomerate at Lisbellaw, Co. Fermanagh, which he believes 
to have been formed in Silurian times after the manner of the 
Chesil Bank. “In Lyme Bay the flow tide current runs from the 
westward of Portland Bill which acts as a groyne; Chesil Bank or 
Beach becomes coarser and larger as it is followed east, till it forms a 
massive heap of shingle to the west of the Bill; but eastward of the 
Bill, in Weymouth Bay, there are finer accumulations. In Silurian 
times similar forces were at work in the neighbourhood of Lisbellaw.” 
