290 Geological Progress. 
they will believe nothing, if they cannot see it, until they are 
obliged, and fight in defence of their scepticism like soldiers 
for their country. 
We have recently seen this characteristic most excellently 
displayed in several discussions on theoretical subjects, espe- 
cially in the controversies on the modes of formation of lake- 
basins and river-valleys. Field-geologists have, indeed, lately 
aroused from the lethargy in which their theory-forming facul- 
ties had so long lingered, and some of them have put forward 
hypotheses that have excited the remainder to digress for a — 
while from their more general and more profitable occupation 
of fact-finding. Thus, Professor Ramsay’s memoir on the 
Formation of Lake-basins produced a desultory discussion 
which commenced three years ago, and still continues. In the 
April number of the ‘ Philosophical Magazine,’ the enunciator of 
this theory replied tc Sir Charles Lyell’s remarks in the new 
edition of his ‘ Elements ;’ but this pamphlet has already been 
noticed in the GEoLoGICAL MaGazine.* More recently, 
Mr. John Carrick Moore has shown that Professor Ramsay has 
been a little forgetful of the laws of dynamics, while many 
other geologists, including the Presidents of the Geographical 
and Geological Societies (in their anniversary addresses), Dr. 
Haast (in the last number of the Geological Society’s Journal), 
and Mr. Ruskin in this Magazine, have taken part in the con- 
troversy on behalf of one view or the other, without contributing 
very much towards its solution. But, in fact, we cannot expect 
a question of this kind to be definitively solved and settled. It 
must always remain, for instance, a matter of opinion whether 
a large rock-basin like that of the Lake of Geneva was or 
was not scooped out by glaciers, unless some mathematician of 
acknowledged authority steps forward and proves that ice could 
not perform such a feat. For if it were absolutely proved that 
ice could scoop out a hollow in a hard rock, it would still be 
uncertain, without strong corroboratory evidence, whether this 
were the mode of formation of any particular rock-basin. In- 
deed, it is much easier to assail an hypothesis of this kind than 
to defend it; and accordingly the several lines of argument 
adopted by its opponents appear much stronger than the argu- 
ments hitherto put forward in its favour, as in many cases Pro- 
fessor Ramsay and his adherents cannot, from the nature of the 
objections advanced by those opposed to his theory, bring for- 
ward facts in direct contravention of them. Such is the case, 
for instance, in regard to the alleged incapacity of a glacier to 
excavate a deep rock-basin after it has emerged from a deep and 
* Vol. II. p. 212. t Phil. Mag., June 1865, Supplement number, p. 526. 
