166 
MISCELLANEOUS NOTICES <&C. 
of a region the rocks of which have been more or less transformed, 
/ 
siiicified, ferruginated or ironmasked, in the progress of the plutonic 
developement which elevated and moulded it. There may however 
be considerable tracts, as there are small tracts in every district, which 
have escaped the stronger attacks of the subterranean powe rs, and 
should coal beds occur in such, the lesser plutonic influence which 
has been exerted on them may have been advantageous instead of 
the reverse. 
The surface layer broken through to reach the coal and said to con¬ 
tain shells, is a congloineritic sand, partially ironmasked. The speci¬ 
mens which wehave seen contain no shells, but some fresh barnacles 
and other shells adhere to its upper and under surfaces, which have 
other marks of having been taken from a spot within the range of the 
tide. A portion of a ferruginous vein varying in thickness, and ac¬ 
companied by a lateral ramification and reticulation of thin veins, 
pervades a slab about 2 feet square, and from 6 inches to 1 inch 
thick, in the possession of Colonel Butterworlh. It is in every 
respect similar to one of the common forms of ironmasked rock in 
and near Singaporethe base in the course of the veins being 
merely impregnated and coloured of reddish-brown and blackish co¬ 
lours by-hydrous oxide of iron, although there are spots where the rock 
is completely disguised. On the under side there are small portions 
of the vein where the hydrated peroxide is represented by iron 
pyrites thickly disseminated amongst the sand and pebbles of the 
base; and the appearances at one spot where the passage of the 
latter into the former is distinctly seen leave little doubt that the 
decomposition of the pyrites has produced the hydrated peroxide. 
We have observed similar phenomena in ferruginous dykes in the 
granite of Pulo Besar near Malacca, as well as at other places, and 
both instances, when we consider the facility with which the bi- 
sulphuret of iron decomposes, lend colour to the surmise that the 
ferruginous exhalations with which the Peninsula has been so largely 
penetrated may have more frequently been accompanied by sul¬ 
phur, and originally condensed in the form of pyrites, than the ge¬ 
neral absence of this mineral in the ironmasked rocks seems to 
evince. 
In the Ligor rock the pyritous nests are separated from the 
brownish black ironmasked rock by a narrow irregular band of dull 
