518 Prof. T. G. Bonney—Glacial History of Western Europe. 
But a large part of their cutcrop would disappear before the former 
submergence was completed. . . . The instances, also, of the 
transportation of boulders and smaller stones to higher levels, some- 
times large in amount, as in the transference of ‘brockram’ from 
outcrops near the bed of the Eden Valley to the level of Stainmoor 
Gap, seem to be too numerous to be readily explained by the uplifting 
action of shore-ice in a subsiding area. Such a process is possible, but 
we should anticipate it would be rather exceptional. 
Submergence also readily accounts for the above-named sands and 
gravels, but not quite so easily for their occurrence at such very 
different levels. . . . In other words, the sands and gravels, © 
presumably (often certainly) mid-Glacial, mantle, like the Upper 
Boulder-clay, over great irregularities of the surface, and are some- 
times found, as already stated, up to more than 1200 feet. Hither 
of these deposits may have followed the sea-line upwards or down- 
wards, but that explanation would almost compel us to suppose that 
the sand was deposited during the submergence and the upper clay 
during the emergence; so that, with the former material, the higher 
in position is the newer in time, and with the latter the reverse. 
The passing of the great Ice Age was not sudden, and glaciers may 
have lingered in our mountain regions when Paleolithic man hunted 
the mammoth in the valley of the Thames, or frequented the caves of 
Devon and Mendip. But of these times of transition before written 
history became possible, and of sundry interesting topics connected 
with the Ice Age itself—of its cause, date, and duration, whether it 
was persistent or interrupted by warmer episodes, and, if so, by what 
number, of how often it had already recurred in the history of the 
earth—I must, for obvious reasons, refrain from speaking, and content 
myself with having endeavoured to place before you the facts of 
which, in my opinion, we must take account in reconstructing the 
physical geography of Western Europe, and especially of our own 
country, during the Age of Ice. 
Not unnaturally you will expect a decision in favour of one or the 
other litigant after this long summing up. But I can only say that, 
in regard to the British Isles, the difficulties in either hypothesis 
appear so great that, while I consider those in the ‘land-ice’ hypothesis 
to be the more serious, I cannot, as yet, declare the other one to be 
satisfactorily established, and I think we shall be wiser in working 
on in the hope of clearing up some of the perplexities. I may add 
that, for these purposes, regions like the northern coasts of Russia and 
Siberia appear to me more promising than those in closer proximity to 
the North or South Magnetic Poles. This may seem a ‘“‘lame and 
impotent conclusion” to so long a disquisition, but there are stages in 
the development of a scientific idea when the best service we can do it 
is by attempting to separate facts from fancies, by demanding that 
difficulties should be frankly faced instead of bemg severely ignored, 
by insisting that the giving of a name cannot convert the imaginary 
into the real, and by remembering that if hypotheses yet on their trial 
are treated as axioms, the result will often bring disaster, like building 
