PHESlDliNT’s ADOUESS. 
IGl 
times be a correct one, and that from it was derived part of 
the flora and fauna which now tenant our earth, it doubtless also 
afforded the highway for the translation of animal forms between 
tlie two Continents referred to by Wallace, w’ho, in his great work 
(‘ 'I'he Geograpliical Distribution of Animals,’ vol. i. p. 142) in 
summing up the general relations of the extinct Tertiary 
^lammalia of JN’orth America and Europe, draws this memorable 
conclusion : — “ If then the facts at present known represent 
approximately the real time-relations of the groups in question on 
the two continents, they render it probable that Weasels, Dears, 
true Horses, Swine, Oxen, Sheep, and Antelopes, originated on the 
t)ld World continent, and w'ere transmitted to America during some 
part of the Miocene period ; while Camels originated in the New 
World, and somewhere about the same time passed over to Europe. 
Of the genera common to the two countries, almost all seem to 
liave had a European origin, the only genera of equal date being 
the two Khinoceroses and three Anchitheridye ; but if the 
Brontotheridse are allied to the llhinocerotidic, these latter may 
have originated in America, although now an exclusively Old 
AVorld typo.” I will, however, candidly admit that the theory 
I have here advanced in regard to the distribution of these animal 
forms is mainly based on hypothesis, but still I think one 
deserving of your reflection ; for if I have offered you a j^aucit}’ 
of facts, it is possible that my theories may induce some amongst 
you to consider the subject, with the result of adducing fresh facts 
to support it. This much may be said in favour of the argument, 
that such facts as are known do not seem to contradict it. 
If wo accept as a fact the existence of a Polar continent in 
^Miocene times around the Xorth Pole, such a land surface must 
have exercised a most potential effect during the later periods 
of geological time, as a surface for the accumulation of snow and 
ice around the Xorth Pole ; therefore it appears to me incumbent 
that I should allude as briefly as possible, to that important 
episode in the recent geological history of the northern hemisphere 
which is styled the Glacial epoch, and which undoubtedly has 
VOL. IV. 
