lS-l/\] including Notices of Sumatra, the Malay Peninsula, §c. 6*83 



their sides and the interstices filled with a black ferruginous substance 

 sometimes dull and sometimes shining (apparently hydrated oxide of 

 iron) and of quartz holding a similar substance in seams also occur. 

 One of the largest and boldest cliffs has been converted into a compact 

 siliceous rock pervaded by numerous quartzose and ferruginous dykes 

 and veins. In some places a complete net-work of fissures ramifies 

 through the rock, and it is evident that quartzo-ferruginous gas or 

 vapour has been injected through these fissures and the large veins 

 and dykes, and metamorphosed the rock. 



At the Water Islands south of Malacca, and at Tanjong Panchur 

 and Budewa to the north, I carefully examined some large developments 

 of granitic rocks. In the former I found some dykes composed of 

 quartz felspar and a ferruginous substance similar to that already 

 noticed. In decomposed felspar and also in solid quartz in those dykes 

 I found much both of decomposed and of undecomposed iron pyrites. 

 Although these dykes seem to countenance the idea that the plutonic 

 agency which has so greatly affected the superior rocks was exerted 

 after the formation of the upper granite, I have from all my observa- 

 tions come to a different conclusion. I cannot now state its grounds, 

 and I do not positively bind myself to an opinion to which perhaps I 

 cannot demonstrate beyond doubt to be correct, but the result of my 

 constant consideration of the subject in all its relations, and with 

 reference to every new locality that I have explored, is as follows : — ■ 

 The whole region has been subjected to plutonic reduction. The 

 plutonic fluid by its pressure has caused fractures in N. W. S. E. lines, 

 and it has swollen up in ramifying bands having that general direction. 

 Its pressure and heat have varied at different portions of its surface. 

 In some places the heat has been so intense as to reduce all the super- 

 incumbent rock up to the very surface into its own substance, and it 

 lias swollen up into mountains in the interior and hills in the exterior 

 lateritic tracts of the Peninsula. 5 " 



* This is opposed to prevalent theory, and it may be asked whether in that case it 

 would not have flowed over? But I have found it impossible to apply the prevalent 

 plutonic theory, — I mean that of a necessarily Tartarean origin of granite, &c.,— to the 

 granites of the south of the Peninsula, considered even perse, and I would ask in return 

 whether there is any proof or probability that granite prior to solidification ever exists 

 in the upper crust of the globe in any other form than as a viscid cohesive mass. Lei 

 Fig. 1, PI, XXII. be the surface of a plutonic bubble swelling up and reducing 



