BORNEO 
217 
with them a tolerably advanced civilisation, as we can see 
from Pigafetta’s description, their influence did not pene¬ 
trate far into the interior. 
3. Geology and Physical Features. 
Borneo in pre-Tertiary days exhibited a very different 
configuration from that of the present time. It consisted 
almost certainly of a mass of islands, now represented 
by the central range, Kinabalu, the Sarawak and 
western districts, the Tana Laut Mountains, etc., which 
in geological structure resembled the islands of Bangka 
and Blitong. In his work on the geology and minera¬ 
logy of Borneo, Dr. Theodor Posewitz remarks that in 
this ancient archipelago crystalline schists played only 
a subordinate part. “ The rocks ' belonged mainly to 
the ‘ Old Slate Formation ’ of Devonian age, and in the 
northern portion of the islands to the Carboniferous. 
The stratigraphical position of these strata was dis¬ 
turbed by the eruption of igneous rocks, granites, and 
diorites. The eruption took place partly after the forma¬ 
tion of the Devonian, partly in pre-Devonian times. . . . 
Then began a deposition of sedimentary matter in the 
seas surrounding the islands. The Eocene strata contain¬ 
ing the thick coal-beds were formed, and then disturbed 
by the eruption of andesite. Further, younger Tertiary 
beds containing brown coal were deposited. The separate 
islands were now united, the Tertiary beds being de¬ 
posited not only between them, but also as a belt on all 
sides. The configuration of Borneo was thus brought 
nearer to its present shape, first acquiring a form similar 
to that possessed at the present day by the neighbouring 
island of Celebes. Wide arms of the sea ran far into the 
