160 
ELEMENTS OF GEOLOGY. 
the limitation of particular genera or families of quadrupeds, 
mollusca, etc., to certain existing provinces of land and sea, 
began before the larger part of the species now contempora¬ 
ry with man had been introduced into the earth. 
Professor Owen, in his excellent History of British Fos¬ 
sil Mammals,” has called attention to this law, remarking 
that the fossil quadrupeds of Europe and Asia differ from 
those of Australia or South America. We do not find, for 
example, in the Europseo-Asiatic province fossil kangaroos, 
or armadillos, but the elephant, rhinoceros, horse, bear, hy¬ 
aena, beaver, hare, mole, and others, which still characterize 
the same continent. 
In like manner, in the Pampas of South America the skele¬ 
tons of Megatherium, Megalonyx, Glyptodon, Mylodon, Tox- 
odon, Macrauchenia, and other extinct forms, are analogous 
to the living sloth, armadillo, cavy, capybara, and llama. 
The fossil quadrumana, also associated with some of these 
forms in the Brazilian caves, belong to the Platyrrhine fam¬ 
ily of monkeys, now peculiar "to South America. That the 
extinct fauna of Buenos Ayres and Brazil was very modern 
has been shown by its relation to deposits of marine shells, 
agreeing with those now inhabiting the Atlantic. 
The law of geographical relationship above alluded to, be¬ 
tween the living vertebrata of every great zoological prov¬ 
ince and the fossils of the period immediately antecedent, 
even where the fossil species are extinct, is by no means con¬ 
fined to the mammalia. I^ew Zealand, when first examined 
by Europeans, was found to contain no indigenous land quad¬ 
rupeds, no kangaroos, or opossums, like Australia; but a 
wingless bird abounded there, the smallest living represent¬ 
ative of the ostrich family, called the Kiwi by the natives 
{^Apteryx). In the fossils of the Post-pliocene period in this 
same island, there is the like absence of kangaroos, opos¬ 
sums, wombats, and the rest; but in their place a prodigious 
number of well-preserved specimens of gigantic birds of the 
struthious order, called by Owen Dinornis and Palapteryx^ 
which are entombed in superficial deposits. These genera 
comprehended many species, some of which were four, some 
seven, others nine, and others eleven feet in height! It seems 
doubtful whether any contemporary mammalia shared the 
land with this population of gigantic feathered bipeds. 
Mr. Darwin, when describing the recent and fossil mam¬ 
malia of South America, has dwelt much on the wonderful 
relationship of the extinct to the living types in that part 
of the world, inferring from such geographical phenomena 
that the existing species are all related to the extinct ones 
which preceded them by a bond of common descent. 
