568 Reports and Proceedings—Duke of Aryyll’s Address. 
fresh-water as against marine currents on the plea that sea-water 
would have sifted the smaller animals trom the larger, and would not 
have deposited them all in one place. So far as I know, marine 
currents would act upon carcases precisely in the same manner as 
currents of fresh water, and neither of them would separate drowned 
beasts according to their size. Surely the opposite assumption arises 
from a confusion of thought, because in so far as water sorts and sifts 
materials which fall into it, the sorting and the sifting depends on 
differences of specific gravity. But the specific gravity of animal 
carcases does vary with the size of the animal. A dead cat is very 
much the same specific gravity as a dead donkey, and a dead beaver 
would float readily alongside of adead mammoth. But really it matters 
little whether the eddies which carried these carcases in such numbers 
are supposed to have been marine or fresh. The question equally 
remains how these rivers came to be in such roaring flood, and to be 
charged with the dead bodies of animals floating and eddying pell- 
mell together. Then, again, in a distant but over an immense area of 
the globe we are confronted by the problem of the sudden destruction 
of the Mammoth and its contemporaries, now preserved in millions in 
the Tundras of Siberia from the Gulf of Obi to Behring’s Straits. 
The facts upon this poimt, as well as on many others, have lately been 
collected and presented, in their mutual bearing and connection, in 
the very able papers of Mr. Howorth contributed to the GxroLoeicaL 
Maeazine. One main fact and difficulty in the problem presented to 
us is the preservation of many carcases in the flesh by having been: 
frozen up immediately after death, and never having been unfrozen from 
that date to the date of discovery in our own times. The difficulty 
may be stated thus :— Under glacial conditions so severe these animals 
could not have lived, whilst at the same time, under glacial conditions 
equally severe, these animals must have died. From this dilemma I 
can only see one method of escape. It seems to compel us to believe 
in a rapid congelation accompanied by an inundation. The sudden 
advent of very hard frost within the limits of our own climate is a 
familiar phenomenon. . But we must suppose the advent, with at least 
a like suddenness, of a cold far more extreme, and of a permanent 
refrigeration of all the seasons. I propound no theory as to the 
explanation of facts so unquestionable and yet so mysterious. I am 
quite sure there has been no break in the perfect continuity of physical 
causation. But I am disposed to think that this very continuity has 
brought about, and that suddenly, some very extensive and very violent. 
changes in those configurations of sea and land which have the most 
powertul effect on climate. 
Lastly, I desire to point to the earliest traces of mankind, and to the 
conditions under which they have been found, as another great pro- 
blem of Pleistocene geology on which the prepossessions of the Uni- 
formitarian theory have prejudiced the natural interpretation of facts. 
And be it remembered that this is the loftiest theme which belongs to 
our science. It is, indeed, the loftiest theme which belongs to any of 
the physical sciences. There is not one of them which teaches any 
fact, or even deals with any conception, so significant or so impressive 
as the fact that the birth of man is a thing of yesterday. And if there 
