106 = Prof. Edw. Hulli—Submergence of the British Isles. 
icebergs, he says with reference to the question of submergence: 
“ From circumstances presently to be mentioned, it is to me certain, 
that at a time when North Wales was so far submerged that only 
the higher mountain tops rose as islands, none of them more than 
about 2000 feet” above the surface, ete. (Old Glaciers of North 
Wales, p. 96). This is the deliberate opinion of one who, as 
Director of the Geological Survey, and as taking an active personal 
part in the work in North Wales for several years, had become 
familiar with every spot and section where the Glacial deposits were 
visible ; and was investigating the phenomena of glaciation with the 
enthusiasm which their novelty at the time inspired. It is true that, 
as Ramsay himself determined, the ice-sheet of the Irish Channel 
was sufficiently thick to pass across Anglesea, and the low ground 
adjoining the Menai Straits in a S.W. direction; but there is no 
evidence whatever that it ascended the mountain slopes around 
Snowdon to a level of 1400—1500 feet above the present surface. 
It is in such Marine Drift deposits as those above described that the 
shells occur, not only at Moel-Tryfan, but in several other places, 
such as the valleys which descend from Carnedd Llewelyn, at 
elevations of about 1200—1300 feet and also in Denbighshire. | 
Then as regards Ireland, the evidence is quite as conclusive. The 
shell-beds which were discovered by Mr. John Kelly, and the Rev. 
Maxwell Close, at Caldbeck Castle, at 1300 feet, and in several 
other localities, not so elevated, amongst the Wicklow Mountains, 
are by no means solitary representatives of submergence. They 
are detached portions of the shelly gravels of Wexford which reach 
levels of 300—400 feet, and of the great deposits of sand and gravel 
which cover such large tracts of the central plain of Ireland, up to 
levels of several hundred feet, and in which sea-shells have been 
found at various elevations, as in the Dargle Valley, at spots west of 
the Sugarloaf Mountain, and south of HEnniskerry, county Wicklow, 
up to heights ranging from 500 or 600 up to 1000 or 1200 feet 
according to Jukes (Manual of Geology, 8rd edit. p. 709). They 
have also been found in more inland places. But the presence or 
absence of shells in these deposits is of very little consequence; the 
beds are the same, whether shells have been found in them or not; 
and it is easy to conceive how shells, originally contained, may have 
been dissolved out of them by percolating rain-water. That the 
shell-gravels of the central plain of Ireland are the same deposits as 
those which contain shells in the higher elevations, and that they 
are the result of submergence is the clear opinion of the late Prof. 
Jukes (Ibid. p. 710). If they had been formed by an ice-sheet, that 
ice-sheet must have moved from the sea and spread itself over the 
land-surface of Central Ireland, but this is exactly the reverse of the 
case, as shown by the glacial striae and the roches-moutonnées. These 
have all been observed and tabulated in detail over the whole 
country by Mr. Close, the Geological Surveyors, and others, and 
will be found laid down on my map of the General Glaciation of 
Ireland (Phys. Geol. of Ireland, 2nd edit. p. 211), from which it will 
be seen that the movement of the great ice-sheet was everywhere 
