184/.] including Notices of Sumatra, the Malay Peninsula, fyc. 673 



At the southern extremity of the western St. John's (Pulo Sikijang) 

 two adjoining hills have been formed by strata being bent into a 

 convex shape — rising only a few feet above the level of the beach. 

 There is a remarkable approach to uniformity in the strike of all 

 the strata and in the direction of the hill ranges. Speaking ge- 

 nerally, it may be said to approximate to N.W. — S. E. The hills 

 have commonly mamillary surfaces. The ranges may be said to 

 consist of distinct hills bulging out and united at their sides. The 

 central hills are generally the more bulky. Lateral hills ramify on 

 each side to a short distance. The whole connected system is disposed 

 in a symmetrical ramose manner, indicating a wonderful uniformity in 

 the mode of operation of the dynamical forces which produced them. 

 The investigation of the forms of these hills, and of the laws of the 

 mechanical forces of which they are the result, assumes a high interest 

 and importance when we find that these forms are not confined to 

 Singapore, but are repeated in low hill ranges over large portions of 

 the Peninsula, Sumatra, Southern India, Northern India, Northern 

 Australia, &c, and accompanied, as I believe, by volcanic phenomena 

 of exactly the same nature as those which I have described. I do not 

 say that the phenomena are identical at all points. In Singapore itself 

 they vary almost infinitely. But they are always analogous, frequently 

 the same, and, to my mind, are undoubtedly the product of one well, 

 marked species of volcanic* action. 



I should not omit to notice the frequent occurrence, in those ranges 

 which have been most burnt, of mounds or monticules of scoreous 

 blocks, sometimes on the summits, and sometimes bulging out from 

 the sides of hills. The ridges and angles of hills appear frequently 

 to present scoreous blocks. 



The valleys between the long hill ranges are, in Singapore, perfectly 

 flat, so that they display the outlines of the bases of the ranges almost 

 as well as if they still remained what they were at no very remote 



* In reference to the igneous changes which the rocks have undergone, I use the 

 words volcanic and plutonic indiscriminately, because a minute examination of some of 

 the best marked developments of crystalline rocks (graduating from basaltic to granitic 

 types) at the extremity of the Peninsula, has led me to think that though the distinction is 

 useful and appropriate in some regions, the theory which it expresses is not sound as a ge- 

 neral one— at least as expounded by many Geologists. 



4 s 2 



