9HMKJM - The Complete Work of Charles Darwin Online

114
DARWIFIAFA.
faunas and floras, and in nearly the same proportions
and the same diversities as at present. The faunas of
what is now Europe, Asia, America, and Australia,
differed from each other much as they now differ : in
fact— according to Adolphe Brongniart, whose state-
ments we here condense '— the inhabitants of these
different regions appear for the most part to have ac-
quired, before the close of the tertiary period, the
characters which essentially distinguish their existing
faunas. The Eastern Continent had then, as now, its
great pachyderms, elephants, rhinoceros, hippopotamus
; South America, its armadillos, sloths, and ant-
eaters ; Australia, a crowd of marsupials ; and the very
strange birds of ISTew Zealand had predecessors of simi-
lar strangeness. Everywhere the same geographical
distribution as now, with a difference in the particular
area, as respects the northern portion of the continents,
answering to a warmer climate then than ours, such
as allowed species of hippopotamus, rhinoceros, and
elephant, to range even to the regions now inhabited
by the reindeer and the musk-ox, and with the serious
disturbing intervention of the glacial period with-
in a comparatively recent time. Let it be noted also
that those tertiary species which have continued with
little change down to our days are the marine animals
of the lower grades, especially mollusca. Their low
organization, moderate sensibility, and the simple conditions
of an existence in a medium like the ocean,
not subject to great variation and incapable of sudden
change, may well account for their continuance;
while, on the other hand, the more intense, however
1 In Comvfes Rendus, Academie des Sciences, February 2, 1857.