f)26 On the Local and Relative Geology of Singapore, [June, 



The bills of the first and second ranges in the order in which they 

 arc above noticed consist chiefly of sandstone (fine grained, gritty and 

 conglomeritie) and shale strata. Towards the eastern extremities of 

 (be two next ranges similar rocks are observed. Further on soft clays 

 of various hues, but mostly mottled white and red or purplish, passing 

 into a soil of different shades of red, yellowish red, and brownish red, 

 are observed near the surface, and occasionally protruding blocks of 

 sienite and green-stone occur. The hills of the eastern side of the 

 Island seem to be principally sandstone with slight traces of shale. 

 The western side is also for the most part sandstone and shale. At 

 the N. E. extremity granite or sienite appears and it is also seen at 

 several places along the N. and N. "W. coast. 



The superficial deposits which occur at various places are very remark- 

 able. On some hills a red stiff clay resembling laterite is found. On 

 many, imbedded in clay of different red and brownish hues, in irregular 

 sheets or in thin seams, occur blocks of a ferruginous clay, rock or 

 smaller stones and pebbles of various kinds and sizes. These will best be 

 described hereafter by selecting particular localities where they abound. 



I now proceed to notice the different hypothesis that have been or 

 may be suggested to account for these appearances. Of the alluvial 

 plains and valleys which ramify through the Island in all directions I 

 need say nothing here, as they, in exposed beds at least, have all or 

 nearly all been formed subsequent to the hills and their "superjacent 

 deposits, and are separated from the latest accessions of matter which 

 these received at a period when they formed a multitude of little bays 

 and long narrow inlets of the sea. 



The first class of the hypothesis that may be offered in explanation 

 of the superficial formations of Singapore, embraces those that contem- 

 plate merely the position, external appearance and size of the detached 

 rock fragments. 



1. — Alluvial Hypothesis. 



Of these the first supposes the blocks, gravel, &c. to be the debris 

 of older rocks deposited in the sea before the extrusion of the hills. If 

 it be conceived that the elevation of the hills above the level of the 

 sea was the same act with the protrusion of the strata of which they 



