290 J. B. Scrircnor — T/ie Sediiiioifar// Rochs of Singapore. 



that under the circumstances it would be unsafe to assume an extension 

 of the Tembeling Series in Singapore until more definite evidence was 

 forthcoming. 



The Tembeling Series consists of shale, sandstone, and conglomerate. 

 The shales are sometimes deep red, sometimes grey ; while the sand- 

 stone and conglomerate are leraarkable for containing derived fragments 

 of chert, and sometimes of black carbonaceous shale also. In Singapore 

 the sedimentarj' rocks consist chiefly of fine sandstone and deep red 

 and grey shales. 



Prior to the discover}^ of the fossils described by ]\[r. Xewton only 

 a little coarse sandstone had been seen by the writer in Singapore, and 

 it seemed essential to prove the presence of chert pebbles in either 

 sandstone or conglomerate before including the Singapore rocks in the 

 Tembeling Series. 



Early in 1907 an opportunity presented itself of devoting several 

 days to a further examination of the Singapore beds, with the result 

 that the presence of chert pebbles was proved in both sandstone and 

 conglomerate. The best sections were found at the west end of 

 Blakang Mati, a fortified island guarding Singapore Harbour. Access 

 to these sections was kindly permitted by the military authorities. 

 The west end of Blakang Mati is composed of red and grey shales, 

 sandstone and conglomerate. The beds are vertical. The general strike 

 is N.AV.-S.E. There are several bands of fine conglomerate, all showing 

 chert pebbles ; and near a point marked " Chupa Rock " on the 1904 

 map of Singapore, by the Colonial Engineer and the Surveyor General, 

 a band of coarse conglomerate is exposed in a deep cleft between 

 a large isolated mass of rock and the cliff. This also contains chert 

 pebbles and other pebbles to be noted later. 



Again, in the grounds of the municipal filter beds, behind Government 

 House, grey and red shales and sandstone are exposed. Here also 

 fresh specimens show that the sandstone contains fragments of chert. 



In the writer's lleport of Progress it is assumed that the presence 

 of the chert pebbles in the conglomerate of the Tembeling Series in 

 Pahang shows an unconformity between the Tembeling Series and the 

 Paub and the Chert Series. It was pointed out, however, in this 

 report, that pebbles of the Pahang Volcanic Sei'ies, which one would 

 expect in the conglomerate also, had not been found, but that little 

 time had been spent in searching for them. In the "Chupa Rock" 

 section on Blakang Mati several pebbles of pale-green partially de- 

 composed lava were found (probably andesite or dacite), agreeing with 

 some of the Pahang rocks ; and a subsequent comparison of these 

 pebbles with the material of specimens of sandstone from Pahang 

 showed that small, soft, pale-green fragments in the sandstone are 

 probably decomposed lava also. The pebbles in the Singapore con- 

 glomerate were well enough preserved for microscopic examination. 



It may be noted here that Pahang Volcanic Series x'ocks are known 

 to occur in Singapore as rough boulders which are probably hard 

 ' cores ' left from beds now weathered away. The writer has not yet 

 seen any such rocks in Singapore clearly in situ. 



One large chert pebble from the " Chupa Rock " section was cut 

 for microscopic examination. The slides show abundant obscure 



