lvi PROCEEDINGS OF THE GEOLOGICAL SOCIETY, 
isting fauna of the same province, as a whole, the component elements 
of the fauna were differently associated. In the Miocene epoch, 
North America possessed Elephants, Horses, Rhinoceroses, and a 
great number and variety of Ruminants and Pigs, which are absent 
in the present indigenous fauna; Europe had its Apes, Elephants, 
Rhinoceroses, Tapirs, Musk-deer, Giraffes, Hyzenas, great Cats, EHden- 
tates, and Opossum-like Marsupials, which have equally vanished 
from its present fauna; and in Northern India, the African types 
of Hippopotamuses, Giraffes, and Elephants were mixed up with what 
are now the Asiatic types of the latter, and with Camels and Sem- 
nopithecine and Pithecine Apes of no less distinctly Asiatic forms. 
In fact the Miocene mammalian fauna of Europe and the Hima- 
layan regions contains, associated together, the types which are now 
separately located in the South-African and Indian subprovinces of 
Arctogeea. Now there is every reason to believe, on other grounds, 
that both Hindostan, south of the Ganges, and Africa, south of the 
Sahara, were separated by a wide sea from Europe and North Asia 
during the Middle and Upper Eocene epochs. Hence it becomes 
highly probable that the well-known similarities, and no less re- 
markable differences, between the present Faune of India and South 
Africa have arisen in some such fashion as the following. Some time 
during the Miocene epoch, possibly when the Himalayan chain was 
elevated, the bottom of the nummulitic sea was upheaved and con- 
verted into dry land, in the direction of a line extending from 
Abyssinia to the mouth of the Ganges. By this means, the Dekhan 
on the one hand, and South Africa on the other, became connected 
with the Miocene dry land and with one another. The Miocene 
mammals spread gradually over this intermediate dry land, and if 
the condition of its eastern and western ends offered as wide con- 
trasts as the valleys of the Ganges and Arabia do now, many forms 
which made their way into Atrica must have been different from 
those which reached the Dekhan, while others might pass into both 
these subprovinces. 
That there was a continuity of dry land between Europe and 
North America during the Miocene epoch, appears to me to be a 
necessary consequence of the fact that many genera of terrestrial 
Mammals, such as Castor, Hystriv, Elephas, Mastodon, Equus, Hip- 
parin, Anchithertum, Rhinoceros, Cervus, Amphicyon, Hycnarctos, 
and Machairodus, are common to the Miocene formations of the two 
areas, and have as yet been found (except perhaps Anchitherium) 
in no deposit of earlier age. Whether this connexion took place by 
the east, or by the west, or by both sides of the Old World, there is 
at present no certain evidence, and the question is immaterial to the 
present argument; but, as there are good grounds for the belief that 
the Australian province and the Indian and South-African subpro- 
vinces were separated by sea from the rest of Arctogsea before the 
' Miocene epoch, so it has been rendered no less probable, by the in- 
vestigations of Mr. Carrick Moore and Prof. Duncan, that Austro- 
Columbia was separated by sea from North America during a large 
part of the Miocene epoch. 
