222 MR. A. H. EVERETT ON THE ZOO-GEOGRAPHICAL [ Apr. 16, 
pines. The significance of such a condition of things in the sub- 
marine geography of the area between Borneo and the Philippines is 
too well understood to render it necessary to enlarge upon it here ; 
and if the settlement of the point at issue depended upon considera- 
tions of physical geography alone, it would probably be at once 
conceded by all that to include the Palawan group as an integral 
part of the Philippine sub-area is to draw a purely arbitrary line of 
delimitation somewhere through the Balabac straits and to the 
westward of Cagayan-Sulu and Sibutu, instead of adopting the 
natural boundary which soundings demonstrate to exist already in the 
Mindoro and Sibutu straits. 
But the geographical evidence for the connexion here advocated, 
though valuable in so far as it shows that a very slight elevation of 
the sea-bed would suffice now, and may have sufficed in the past, to 
join the Palawan group to Borneo, while one of considerable magni- 
tude would be required to effect a junction with the Philippines, 
is not of convincing weight unless it can be shown that it is con- 
firmed by the characteristic features of the Palawan fauna. For if 
we were to rely on the argument of physical geography alone, we 
should be confronted with the fact that Celebes might just as well 
be regarded as having been directly connected in recent geological 
time with Borneo, since that island also is apparently linked to the 
latter by a broad band of submarine bank, on which the soundings 
are everywhere, so far as is ascertained, less than 100 fathoms. And 
as this argument might be advanced, and this bank in the Straits of 
Macassar is a real difficulty, in view of the extreme dissimilarity 
of the faunas on either side of that strait, I may be permitted to 
digress for a moment before proceeding to examine the Palawan 
fauna, aud to point out that in consequence of local circumstances, 
which are absent in the case of Palawan, this apparent evidence of 
a recent land-connexion between Borneo and Celebes is susceptible 
of being otherwise interpreted. The interpretation has been suggested 
by Mr. Wallace, who remarks’: ‘‘ 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 40 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 Baly to Timor rise out of a deep ocean, the few soundings 
we possess showing depths of from 670 to 1300 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 voleanic 
upheaval, or by coral reefs. Such shallow seas, 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.” 
The rainfall in Borneo is enormous, and the country is largely made 
1 «Tsland Life,’ p. 425. 
