Prof. P. F. Kendall—The Glaciation of Ireland. 53 
on-Shannon is made. to swerve round the west side of the Shieve 
Bloom Mountains, instead of, as Wright represented it, down the 
east side near the famous Maryboro esker, the error is perhaps 
accountable for Professor Gregory’s mistaken supposition that this 
esker was “‘ probably formed by ice which flowed down the northern 
slopes of the Slieve Bloom Mountains”. He might have been 
spared this mistake had he consulted the Geological Survey memoir 
explanatory of Sheets 117-18 of the year 1866, which states that 
boulders of the Galway granite “are not so large or abundant on 
the northern as on the southern slopes of the Sieve Bloom Moun- 
tains”. The Roscrea esker is by Professor Gregory included in the 
same explanation, but unfortunately it is not at the northern end 
of the mountains but a few miles south-west of the southern end. 
Professor Gregory insists that the eskers were formed under water, 
and he assigns an arbitrary limit of 400 feet as the water-line, 
though in order to do this he finds it necessary without other apparent 
justification to put the Tyrone ridges in a separate category. 
The question whether this was lake or sea he decides in favour of 
the sea, remarking: “ The difficulty in the assumption of a glacial 
lake is to account for the containing barriers.”” Without labouring 
the point, 1 would say that the interpretation of Irish glacial 
geology adopted by all recent workers, except Professor Gregory, 
would without much difficulty provide him with the barriers he 
would need. 
Having settled the marine origin of the eskers the author proceeds 
to disclose a remarkable and hitherto unsuspected change of opinion 
on the part of the British glacial geologists. He says (p. 145), 
‘Some submergence of the British area during Glacial times is now 
generally accepted.” Again, on p. 148, “ It is now generally agreed 
that large parts of the British area were submerged in Glacial times 
to a sufficient height to have flooded the typical esker district of 
Central Ireland.” And finally, with still greater courage, “* Boulder- 
clay, the marine origin of which has been persistently maintained 
in spite of the rejection of that view by, at one time, the great majority 
of British glacial geologists.’ The implications here, and especially 
in the last quotation, are that a great and hitherto undisclosed 
revulsion of opinion has taken place, and that in common with the 
author, who has been sound throughout, the great majority of 
British glacial geologists no longer reject the marine origin of 
boulder-clay. If this is the case, then I can only say that it is the 
_ best-kept secret in geological literature. Where are the signs in the 
Q.J.G.8. or the GrotocicaL Macazine of this change of opinion ? 
Who are the recusants ? I do not think they are to be found in our 
University chairs or in the Geological Survey, and certainly not in 
those of Ireland. 
Though the context shows clearly enough that Professor Gregory 
intends a general assertion of the marine origin of all boulder-clay, 
I do not think he sufficiently realizes that if he and the “ hidden 
