18-17.] including Notices of Sumatra, the Malay Peninsula, §c. 541 



vocally attesting the abrading, sorting, or transporting operation of a 

 large body of water, or which could not be referred to some known form 

 of volcanic agency. It must also be borne in mind that the convulsive 

 mechanical action which enters so largely into the general hypothesis, 

 would be most powerful in shattering compact and loosening soft rocks, 

 when the stratified masses were ruptured and raised into highly in- 

 clined, vertical or reversed positions. In such cases the exposed basset 

 edges, in their fragmentary or pulverized state, and before they were 

 protected by any vegetation, would be more acted on by meteoric causes 

 than at present. 



The system of hills with their dykes and veins affords an interesting 

 field for the application of the principles of mechanical science. But it 

 would be premature to enter on this subject before the country is 

 better opened up, as it will soon be by the lines of road now in pro- 

 gress. There can be little doubt however that the directions of the 

 hills agree with the ramifications of fissures which in those places where 

 the intensity of the elevatory force caused their extension to the sur- 

 face, have formed vents through which the superficial volcanic deposits 

 were expelled. The principal ranges, we have seen, are nearly parallel 

 and have directions approximating to N. W. and S. E. The lateral 

 hills are placed on lines at right angles to these, and the secondary 

 lateral hills again on lines parallel to the principal ranges. 



My remarks have been hitherto confined to facts entirely local, and 

 inferences or hypothesis strictly deduced from, or applicable to them. 

 Before concluding this paper, however, let us extend the limits of our 

 observations, and see whether a wider geological area presents pheno- 

 mena repugnant to the large influence which has been assigned to volca- 

 nic causes. 



That the movements which elevated the central mountains of the 

 Malayan Peninsula had an intimate relation with those that elevated 

 the mountains of Sumatra, seems evident, whether we regard the hypo- 

 thesis of De Beaumont, the more recent observations and theories of 

 Mr. Darwin, or the mechanical researches of Mr. Hopkins. Both 

 form long chains which pursue parallel lines not more than 3 or 4 

 degrees distant. But we must probably take in a much wider geogra- 

 phical range if we would seek a general geological theory for the region 

 which they traverse. The mountain chains of the Peninsula of India 



