93 
GEOLOGICAL FEATURES OF SINGAPORE. 
coherence being very friab'e. It seems however to aid in pre¬ 
serving the stems of trees which lie imbedded in it, but to a li¬ 
mited extent only. 
When burned in contact with the atmosphere the result was 
Carbon,.43. \ This specimen so exa- 
Silex and other earths,. . 2. 75 § mined was from the swam- 
Very magnetic & minute >py flat at the base of the 
grains of protoxide of iron, .25 k western slope of Mount 
Loss,.. 54. /Sophia. 
100 . 
Sir II. Davy shewed that, in general, peat is found to contain 
from 60 to 99 parts of inflammable or destructible matter, the 
residuum being similar to the components of the substratum, with 
some oxide of iron. 
r 
THE IRON STONE, 
Although the ironstone of the Island is most commonly found 
in detached masses, yet there are thin strata of it also. These 
last occur chiefly amongst the upper sandstone and clay layers. 
I am inclined to believe that these masses in most instances are- 
concretionary, but I have in several localities found them in situ, 
either in thin sfrata of irregular thickness, or forming a sort of dyke 
cutting vertically through the clays. This vertical appearance may 
be deceptive, for the clays may have been similarly inclined at first* 
but decomposing and mixing afterwards, may have left the harder 
ironstone by itself. 
U i; 
This ironstone, which has been called by some laterite, has not 
I believe been analyzed. It has been considered I understand to 
contain Manganese, which is probable enough, since Umber, an ore 
of iron, contains that substanes. It exists from the size of coarse 
sand, and smooth small pebbles, up to rounded masses of ten or 
twelve feet in diameter. It has a black or dark clove brown aspect 
externally; sometimes it is scoriatcd; and I have found it botrvoidal, 
and this at the depth of six feet from the surface of the ground. 
Internally it is cellular like aetites—the cells containing the same 
substance as the mass but in a pulverulent state, and of a reddish 
yellow colour. It varies in density, and where hardest does not 
