422 
ISLAND LIFE. 
[part ir. 
united with Greenland, and probably with Europe by way of 
Britain, in the early part of the Tertiary period, and thus 
afforded one of the routes by which that interm igration of 
American and European animals and plants was effected which 
we know occurred during some portion of the Eocene and Mio- 
cene periods, and probably also in the Pliocene. The fauna 
and flora of this island are, however, so poor, and offer so few 
peculiarities, that it is unnecessary to devote more time to 
consideration here. 
There remains the great Malay island — Celebes, which, owing 
to its possession of several large and very peculiar mammalia, 
must be classed, zoologically, as “ancient continental”; but 
whose central position and relations both to Asia and to Australia 
render it very difficult to decide in which of the primary zoological 
regions it ought to be placed, or whether it has ever been united 
with either of the great continents. Although I have pretty 
fully discussed its zoological peculiarities and past history in my 
Geographical Distribution of Animals, it seems advisable to review 
the facts on the present occasion, more especially as the systematic 
investigation of the characteristics of continental islands we have 
now made will place us in a better position for determining its 
true zoo-geographical relations. 
Physical features of Celebes . — This large and still comparatively 
unexplored island is interesting to the geographer on account 
of its remarkable form, but much more so to the zoologist 
for its curious assemblage of animal forms. The geological 
structure of Celebes is almost unknown. The extremity of the 
northern peninsula is volcanic ; while in the southern peninsula 
there are extensive deposits of a crystalline limestone, in some 
places overlying basalt. Gold is found in the northern peninsula 
and in the central mass, as well as iron, tin, and copper in small 
quantities ; so that there can be little doubt that the mountain 
ranges of the interior consist of ancient stratified rocks. 
It is not yet known whether Celebes is completely separated 
from the surrounding islands by a deep sea, but the facts at our 
command render it probable that it is so. The northern and 
eastern portions of the Celebes Sea have been ascertained to be 
from 2,000 to 2,600 fathoms deep, and such depths may extend 
