22 HISTORY OF SANTUBONG, SARAWAK. 
numbers can in a very few years raise the surface of the area 
in which they work through 6 or 7 feet; and no doubt this 
Crustacean has been a most important factor i in the formation 
of dry land from mangrove swamp. 
THE FLORA OF SANTUBONG. 
It will be convenient’ to consider the flora of this island 
uncer several headings according to habitat, that of the moun- 
tain, of the sea shore and of the mangrove swamp. 
3 The mountain flora. The forest of the slopes has all the 
appearance of a truly indigenous flora and is very like that of 
Mt. Matang: it is not in any sense what is known to botanists 
as an island flora. From the evidence of the trees it would 
seem most probable that the two mountains just mentioned 
have in past times been united by high land. Fornot only are 
the two floras so similar throughout but also there isin this 
flora a fair percentage of plants whose means of distribution 
are so limited that they are unable to cross the wide stretch of 
mangrove swamp and of sea which now separates the two 
mountains. Ofsuch plants we may mention in particular the 
. Ironwood tree, Bilian (Husideroxylon zwagert). The fruits of 
the Bilian being large and heavy cannot be blown in the wind 
and as the epicarp is very hard and thick it is not eaten by 
animals (except porcupines) : no doubt it is carried by water 
but streams cannot carry uphill nor-is it probable that Bilian 
will grow in aswamp. Such being the case its wide distri- 
bution in this country argues for it a great antiquity and when- 
ever it occurs on elevated ground there we may expect to find 
primary jungle. Again, there is on Santubong, as also on 
Matang, a number of different species of oak (Quercus) and of 
Engkabangs (Shorea and other dipterocarps) : now the metre fact 
that a given genus of tree has a number of different species in 
one particular locality would lead us to believe that here the 
genus is endemic and when we remember also how imperfect 
is the mode of distribution of the heavier fruited dipterocarps 
and of the oaks we can only suppose that the forest on Santu- 
bong mountain was once quite continuous with that of Matang 
Jour. Straits Branch 
