nent, offers us
some problems of great interest and considerable difficulty.

The accompanying map shows that Borneo is situated on the eastern side of a
submarine bank of enormous extent, being about 1,200 miles from north to
south, and 1,500 from east to west, and embracing Java, Sumatra, and the
Malay Peninsula. This vast area is all included within the 100 fathom line,
but by far the larger part of it--from the Gulf of Siam to the Java Sea--is
under fifty fathoms, or about the same depth as the sea that separates our
own island from the continent. The distance from Borneo to the southern
extremity of the Malay Peninsula is about 350 miles, and it is nearly as
far from Sumatra and Java, while it is more than 600 miles from the Siamese
Peninsula, opposite to which its long northern coast extends. There is, I
believe, nowhere else upon the globe, an island so far from a continent,
yet separated from it by so shallow a sea. Recent changes of sea and land
must have occurred here on a grand scale, and this adds to the interest
attaching to the study of this large island.

{374}

[Illustration: MAP OF BORNEO AND JAVA, SHOWING THE GREAT SUBMARINE BANK OF
SOUTH-EASTERN ASIA.]

The light tint shows a less depth than 100 fathoms.
The figures show the depth of the sea in fathoms.

{375} The internal geography of Borneo is somewhat peculiar. A large
portion of its surface is lowland, consisting of great alluvial valleys
which penetrate far into the interior; while the mountains except in the
north, are of no great elevation, and there are no extensive plateaux. A
subsidence of 500 feet would allow the sea to fill the great valleys of the
Pontianak, Banjarmassing, and Coti rivers, almost to the centre of the
island, greatly reducing its extent, and causing it to resemble in form the
island of Celebes to the east of it.

In geological structure Borneo is thoroughly continental, possessing
formations of all ages, with basalt and crystalline rocks, but no recent
volcanoes. It possesses vast beds of coal of Tertiary age; and these, no
less than the great extent of alluvial deposits in its valleys, indicate
great changes of level in recent geological times.

Having thus briefly indicated those physical features of Borneo which are
necessary for our inquiry, let us turn to the organic world.

Neither as regards this great island nor those which surround it, have we
the amount of detailed information in a convenient form tha