788 MINERALOGICAL DESCRIPTION OF THE ISLAND OF BANKA. 
western extremity of the island. The abundance of Iron in the 
uniting medium of the Poudingues of Sungie Barn has already been 
mentioned; those I met on my further track afford still stronger in¬ 
dications of this abundance. The Iron-ore here is the basis, and 
the particles of the Poudingue adhere to it only in small proportion. 
The veins and beds of these and of the Iron-ores intersect and are 
imposed upon each other in many points, in the space between the 
two rivers and a considerable distance westward of Teluk Robiy&. 
The commencement of this depository of Iron-ore is an extensive 
stratum in conjunction with the district of Poudingues, in the west; 
it composed a length of several hundred yards of the extremity of 
the hill which is washed by the ocean at high tide : it varies in height 
from 20 to 30 feet and is only very superficially covered with soil. 
The ore appears in the stratum in several different forms, but chief¬ 
ly in laminse and nodules. In many portions the lamina? are com¬ 
pact and disposed horizon tally or slightly undulating, in others they 
are arranged obliquely diverging, and leave intermediate spaces 
which are filled by an earthy substance. The colour is black, of va¬ 
rying shades inclining to grey or blueish, and the surface is macu¬ 
lated with yellow ochreous spots. The thickness of the separate la- 
minee varies from several lines to several inches : it often shows it¬ 
self in uniform masses r the fracture is semi-metallic and portions 
of the laminm are often covered with minute crystals. 
From tbe lower termination of this stratum the ore extends near¬ 
ly half a mile towards the shore, stretching at the same time several 
hundred yards east and west. The surface here, which has gene¬ 
rally the same black or blueish colour, exposes principally nodules, 
some of which are of immense size. They appear externally as if 
composed of concentric layers, but on removing them from their 
fixed situation they separate into irregular masses. Tbe fracture is 
more compact and the colour more uniformly of a semi-metallic 
lustre than in the lamime of the large layer above. 
These ores belong to the species of Black-Iron-stone, but many 
of the portions approach the nature of the argillaceous or Bog-Iron- 
ore. The disposition to form regular nodules (which will be exem¬ 
plified in the southern appearances on this depository) is evident in 
many of the fragments of the lower plain, and some of the superior 
layer must be considered as Bog-Iron-ore. Not far from the west¬ 
ern extremity of these strata large rocks of Red-Iron-stone are dis¬ 
persed on the surface, many of which appear as brown ochre more 
