and copper in small
quantities; so that there can be little {452} doubt that the mountain
ranges of the interior consist of ancient stratified rocks.

[Illustration: MAP OF CELEBES AND THE SURROUNDING ISLANDS.

The depth of sea is shown by three tints: the lightest indicating less than
100 fathoms, the medium tint less than 1,000 fathoms, and the dark tint
more than 1,000 fathoms. The figures show depths in fathoms.]

It is not yet known whether Celebes is completely separated from the
surrounding islands by a deep sea, but {453} 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 over a considerable portion of it, or even be
much exceeded in the centre. In the Molucca passage a single sounding on
the Gilolo side gave 1,200 fathoms, and a large part of the Molucca and
Banda Seas probably exceed 2,000 fathoms. The southern portion of the
Straits of Macassar is full of coral reefs, and a shallow sea of less than
100 fathoms extends from Borneo to within about forty miles of the western
promontory of Celebes; but farther north there is deep water close to the
shore, and it seems probable that a deep channel extends quite through the
straits, which have no doubt been much shallowed by the deposits from the
great Bornean rivers as well as by those of Celebes itself. Southward
again, the chain of volcanic islands from Bali to Timor appears to rise out
of a deep ocean, the few soundings we possess showing depths of from 670 to
1,300 fathoms almost close to their northern shores. We seem justified,
therefore, in concluding that Celebes is entirely surrounded by a deep sea,
which has, however, become partially filled up by river deposits, by
volcanic upheaval, or by coral reefs. Such shallows, where they exist, may
therefore be due to antiquity and isolation, instead of being indications
of a former union with any of the surrounding islands.

_Zoological Character of the Islands around Celebes._--In order to have a
clear conception of the peculiar character of the Celebesian fauna, we must
take into account that of the surrounding countries from which we may
suppose it to have received immigrants. These we may divide broadly into
two groups, those on the west belonging to the Oriental region of our
zoological geography, and those on the east belonging to the Australian
region. Of