bends, and all the larger ones are navigable by small steamers for
many miles above their mouths: thus a large steam launch can ascend the
Rejang for 160 miles, the Baram for 120, and some of the rivers on the
Dutch side for still greater distances. The limit of such navigation
is set by beds of rock over which the rivers run shallow, and which
mark the beginnings of the middle reaches. In these middle reaches,
where the rivers wind between the feet of the hills, long stretches of
deep smooth water alternate with others in which the water runs with
greater violence between confining walls of rock, or spreads out in
wide rapids over stony bottoms. The upper reaches of the rivers, where
they descend rapidly from the slopes of the mountains, are composed
of long series of shallow rapids and low waterfalls, alternating at
short intervals with still pools and calm shallows, bounded by rock
walls and great beds of waterworn stones, which during the frequent
freshets are submerged by a boiling flood. The whole river in these
upper reaches is for the most part roofed in by the overarching forest.

Practically the whole of Borneo, from the seacoast to the summits of
the highest mountains, is covered with a dense forest. On the summits
this consists of comparatively stunted trees, of which every part is
thickly coated with moss. In all other parts the forest consists of
great trees rising to a height of 150 feet, and even 200 feet, and of a
dense undergrowth of younger and smaller trees, and of a great variety
of creepers, palms, and ferns. Trees of many species (nearly 500)
yield excellent timber, ranging from the hardest ironwood or BILIAN,
and other hard woods (many of them so close-grained that they will not
float in water), to soft, easily worked kinds. A considerable number
bear edible fruits, notably the mango (from which the island derives
its Malay name, PULU KLEMANTAN), the durian, mangosteen, rambutan,
jack fruit, trap, lansat, banana of many varieties, both wild and