674 On the Local and Relative Geology of Singapore, [July 



period, long narrow inlets of the sea. This circumstance also is not 

 confined to Singapore. 



I will now briefly notice the nature of the sedimentary rocks which 

 have been more or less altered and elevated in the modes I have men- 

 tioned. If you think it worth while, you can, I dare say, procure a 

 copy of Mr. Thomson's Chart of Singapore straits from the Admiralty 

 for reference. It would scarcely be advisable at present to attempt to 

 make a geological map. The southern portion of the Island (including 

 the town, the adjacent district to the N. W ; the ranges between the 

 road from the town to Biikit Tfmah, the central and highest hill, and 

 the sea to the S. W.), and the Islands of Blakan Mati, Pulo Brani, 

 St. Johns, &c, are compossd of shales, clays, sandstones and conglo- 

 merates, the shales predominating. It is impossible to refer these 

 rocks to any place in your European systems, as no organic remains 

 have yet been discovered, and the only rocks with which they are 

 associated are hypogene. In their general appearance and mineralogical 

 characters they agree with the aluminous and arenaceous beds of the 

 new red sandstone. Between the parallel of strike passing through 

 the town and the steep Tulloh Blangan range, there is an area about a 

 mile in breadth, stretching from the sea inland over the Tanjong Pagar 

 and Tanghir districts, and of course in a direction approaching to N. 

 W., and in the opposite direction, including Pulo Brani and the eastern 

 portion of Blakan Mati, composed in great measure of shale strata, 

 although a few of sandstone also occur. The prevailing colours of 

 the shale beds are dull violet, liver brown and chocolate. Beds of 

 the most lively variegated colours sometimes occur motled, striped, 

 damasked, &c , the colours are white, yellow, orange, red, violet, purple, 

 green, bluish and blackish, in addition to the dull violet and chocolate. 

 To the N. E. of this tract sandstone is more frequently interstratified. 

 To the S. "W. sandstones, grits, and coarse conglomerates prevail ; and 

 these are continued, interstratified however with some shales, from the 

 range along the coast of Tulloh Blangan through the western portion 

 of Blakan Mati, and through Sikukur and Sikijang (St. Johns), in a 

 S. Westerly zone. I have not yet pursued this zone further across 

 the strait, but the Island of Sambo, on the other side, is a continuation 

 of the same parallel of elevation, and may consist of the same rocks. 

 To the N. E. of the town, a large alluvial plain sweeps into the coun- 



