552 On the Local and Relative Geology of Singapore, [June, 



with an internal igneous sea, and from time to time emit smoke and 

 gases, that to this day the Island is subject to frequent earthquakes, 

 that several of those that have occurred within the last hundred years 

 have been of great force, rending the ground, and at least on two occa- 

 sions giving vent to liquid volcanic matter, and that their operation 

 extends, though with diminished violence, to the western coast of the 

 Peninsula. When we consider the height arid bulk of the crateriform 

 volcanic mountains even viewed only relatively to the level of the hilly 

 country above which they rise, and the large belts of volcanic rocks which 

 exist in the neighbourhood of some of those that have been explored, if 

 they do not connect the whole chain, we are carried back to a period in 

 the history of Sumatra during which its volcanic phenomena were on 

 the grandest scale. If at this day, when the fires of her mountains 

 have ceased, or are dormant, the coast of the Peninsula is agitated by the 

 comparatively feeble shocks which disturb the repose of the Island, it 

 is reasonable to believe that when her volcanoes, whether simultaneously, 

 successively, or alternately, were in full activity along a line of nearly a 

 thousand miles, the neighbouring regions to the distance of 100 to 200 

 miles must have been subject to earthquakes of great violence, and 

 accompanied, according to the degree of their intensity, by volcanic 

 emissions and eruptions in greater or less abundance. That portion of 

 the volcanic belt where the evidences of violent igneous action are most 

 striking, appears to be Singapore, and the neighbourhood, although it 

 is not improbable that the whole tract from Cape Rachado to Banca, 

 exhibits more extensive and continuous disturbance than the northern 

 part of the belt. That region of Sumatra which, so far as observation 

 has extended, may be termed the principal volcanic tract, is about 3 

 degrees distant from Singapore, and lies in a parallel about a degree 

 and a quarter to the south of this Island. The direction of the Singapore 

 strata is across or approximately at right angles to parallel lines form- 

 ing the sides of a plane connecting the Island with this part of Me- 

 nangkabu, and the dip of the strata although, as formerly observed, 

 exhibiting much irregularity, is generally from the point of the compass 

 where Menangkabu lies. 



There seems, upon the whole, to be strong grounds for the opinion 

 that the hill system of Singapore has its volcanic* connection with 



* Our meagre information regarding the formations of Sumatra does not admit of our 

 instituting a comparison between them and the rocks of the opposite coast of the Penin- 



