718 MINERALOGICAL DESCRIPTION OF THE ISLAND OF BANKA* 
7. Iron-stone consisting 1 of nearly regular alternate bands of dif¬ 
ferent shades of colour, the interior often metallic, the exterior ear¬ 
thy or ochrcous. t 
8. Breccias formed by Red-Iron-stone inclosing numerous sili¬ 
ceous particles. 
On the surface more universally dispersed I observed : 
D. Coarse sand bedded in white and yellow-clay. 
10. Black-clay, the substance above mentioned as occurring 
massive in the strata of most mines. 
I made a seeond excursion from the stockade of Pangkal-pinang 
in an eastern course; on which I observed occasionally some loose 
fragments of Red-Iron-stone on the surface. I arrived at the mines 
of Krdssdk ; they are of a description of small mines but no part of 
the island offers a larger surface from which the ore has been suc¬ 
cessively extracted. 
At two of the works on which the miners had lately been employ¬ 
ed, I noticed the following strata and appearances viz : 
At the first .* 
Soil. 
Fine-sand. 
Particles of quartz mixed with sand, a deep stratum. 
Clay of different colours white and red. The fragments remain¬ 
ing at the canals w 7 ere, with few exceptions, of a siliceous nature. 
At the second: 
Soil. 
Fine sand, mixed thinly with clay of a yellow colour. 
Layer from which the ore had been extracted, consisting chiefly 
of large fragments of quartz and coarse sand, next to this, deep 
layer of variegated clay, red and white ; it was intersected with nu¬ 
merous canals that had served for the former works. 
Pursuing the investigation of the numerous substances which re¬ 
mained on this extensive district from former works I noticed Brec¬ 
cias (or amygdaloids) accumulated in large heaps near the old aque¬ 
ducts at which remained chiefly fragments of siliceous stone: the 
contiguity of these two substances appeared therefore also at these 
mines. The sections of the ground were mostly concealed by re¬ 
turning vegetation, in one place I remarked a deep stratum of sili¬ 
ceous stones bedded in clay of a yellow or red colour. 
Among the substances which I collected as explanatory specimens 
I shall only notice ; 
