THE GEOLOGY OF THE MALAY PENINSULA. 255 
Tertiary of Java. 
The greater part of Java is covered with Tertiary, Quater- 
nary, and Recent deposits, and all the divisions of the Tertiary seem 
to be represented in some part, or other, of the island. The Eocene 
beds include compact clays, marls, and the widespread nummulitic 
hmestones common to this period all over the world. In west 
Java, at Bantam, dolerites and diorites are intercalated with them 
and at Nanggoulan, besides basalts and olivine dolerites, lhgnite 
beds are found interbedded with the sediments. 
The lower Miocene are often very much folded, and may be 
even vertical. Some of the beds were laid down under water, and 
the andesitic lava flows of this period were sometimes laid down 
under the sea, and sometimes on dry land. 
The middle Miocene beds are less strongly developed than the 
lower, and they are typically marly rocks. Pyroxene-andesites are 
interbedded with the series in Bantam and in Preanger, but not 
in east or central Java. The upper. Miocene beds are essentially 
calcareous, sometimes consisting of hard, crystalline limestone, and 
sometimes being soft and marly. They are markedly dolomitic. 
No volcanic rocks are found in this part of the Miocene series. The 
middle and upper Miocene beds are often folded, but usually less 
strongly so than the lower Miocene. 
There have been reports of rich gold deposits being present 
in Java, but there is no foundation for them. A little gold is present 
in the pyrites of certain Miocene clavs which have been altered by 
andesitic flows in the Residency of Krawang, but the commercial 
value of the deposit is negligible. 
Eocene deposits in Bantam contain a good coal, but they are 
so folded, and the position of the one metre seam is made so irregu- 
lar by these foldings, that it would not pay to work. There are 
about two million tons of fuel available here. Lignites of upper 
Tertiary age are known in Nanggoulan and in Bantam. Oil is 
obtained from Miocene beds in many localities, perhaps formed 
from the foraminiferal remains which they contain, 
Tertiary of Borneo. 
In Borneo, in the west, no Tertiary strata are found, this period 
being represented only by andesitic lava flows, whereas, in the south- 
ern, northern, and central parts of the island, Tertiary deposits are 
well developed. In Central Borneo boulders of Eocene age contain- 
ing nummulites are contained in valley gravels, but these anmemrancol sie 
Hocene beds are not met with in situ. A sandstone formation of 
estuarine origin, with interbedded coal seams in Central Borneo, 
is placed in the older Tertiary series. Gienerally the strata are 
horizontal, or only shghtly tilted, but locally they are tilted and 
stronely disturbed and sometimes even vertical. ‘T'wo seams of 
coal, two metres thick are being worked in Eocene beds on the island 
of Poeloe Laoet, off the southeast coast of Borneo. The field is 
estimated to contain eighty million tons of workable coal. 
eA SOC.) No» 86) 19227 
