536 On the Local and Relative Geology of Singapore, [Junk, 



character with the existing superficial strata, and of slaggy and scoreous 

 rocks of which the materials, with the exception of the oxides of iron, 

 might have been derived from similar strata at no great depth. The 

 iron might, on this supposition, have been supplied by beds of ore 

 occurring amongst the carboniferous rocks. 



At present this view is inadmissable ; and it would still remain so 

 even if no other hypothesis derived from analogy were probable. But 

 there have been many volcanoes without streams of lava, from which 

 earth and altered rocks, gases, steam, water, or mud have been ejected, 

 and there are abundant marks of igneous action throughout the series 

 of stratified rocks, proving how frequently volcanic forces have operated 

 from beneath, often without reaching the surface at all, and at other 

 times producing mechanical, igneous, or electrical changes in the super- 

 ficial rocks, unaccompanied by the more marked phenomena of proper 

 volcanoes. 



But the absence of such products in Singapore is not universal, nor 

 are there wanting proofs of the direct connection of the superficial 

 igneous action with a great nether fountain of volcanic power. It is 

 clear that the action reached below the stratified rocks, for in some of 

 the hills near town I have discovered fragments of unaltered sienite, 

 and on one, a large block of sienite passing into basalt, which may 

 either be an ejected fragment, or the protruded summit of a continuous 

 mass, is now being quarried by Chinese. In the Bukit Temah group 

 solid masses of sienite are exposed, and appear to compose a large part 

 of one of the hills. At some places I found it passing into basalt. 

 That the elevation of the sienite and basalt was contemporaneous with 

 the production of the ordinary volcanic or igneous phenomena of 

 Singapore (if the basalt itself was not also then formed) is, to say the 

 least, highly probable. Not only the sides in general, but the summits 

 of the hill, consist of a thick mass of soft ferruginous clay or mould, 

 holding large quantities of the common igneous rocks found elsewhere, 

 but often bearing marks of a more intense igneous action. Thus on 

 the same side of the hill where the sienite and basalt are laid bare I 

 found, in contact with soft sandstone, a piece of compact, dull, igneous 

 rock Jof a light yellowish brown colour, with veins of a violet colour 

 and vesicles whose sides were similar. At the plane of contact, the 

 rock chano-ed into a dark green translncent-glass, which included some 



