﻿430 ME. J. B. SCRIVENOR ON THE HOCKS OF [Aug. I9IO,. 



those islands, at variance with mine as expressed now. Dr. Verheek 

 said that this granite is probably later Palaeozoic, 1 but his state- 

 ment does not appear to have been based on any palaeontological 

 evidence derived from those islands. The radiolarian chert on 

 Billiton only shows the granite to be probably younger than some 

 part of the Palaeozoic. 



Again, in order to emphasize the possibility of the granite-masses 

 of Borneo and the Peninsula being of different ages, it is necessary 

 to quote Mr. Wing Easton's opinion that the granite of a part of 

 Western Borneo either dates from before the deposition of the 

 Triassic beds, or was contemporaneous therewith. 2 



The question remains — is there any known granite-mass in the 

 Archipelago with which we can correlate the granite fragments in 

 the tuff of Pulau Nanas ? Thanks to the invaluable work of 

 Dr. Verbeek, this can be answered in the affirmative. In 1899 

 and again in 1905, Dr. Verbeek described the geology of the Island 

 of Amboyna, in the Banda Sea. 3 In the later publication the 

 author described a series of sandstones and argillaceous schists with 

 interbedded limestones. Fossils were found in the limestones 

 which led to their being referred to the later Palaeozoic, but 

 Dr. Verbeek says that new fossils may show the beds to be 

 Triassic. The important point, however, is that the granite of 

 Amboyna is known to be older than the sandstones : because the 

 latter contain granite-gravel, and there is no trace of action at 

 the granite-contact with the sandstone that can be attributed to the 

 granite, therefore ' the age of the granite cannot then be younger 

 than the Permian.' 4 It is noteworthy, too, that on Amboyna 

 hornblende-granites do not exist as rocks of any extent, and that 

 the granites often contain cordierite. 5 No cordierite has been 

 detected in the granite fragments on Pulau Nanas, but the horn- 

 blende appears to be all of secondary origin, while the younger 

 normal granite of Pulau Ubin is a hornblende-granite. There is, 

 then, at least a strong probability that the granite of Amboyna and 

 the fragments in the tuff of Pulau Nanas belong to the same period 

 of irruption. 



1 ' G-eologische Beschrijving van Bangka & Billiton ' Jaarb. v. h. Mijnwezen 

 in Nederl. Oost-Indie, Wetensch. Gedeelte, vol. xxvi (1897) p. 23. 



a 'Geologie eines Teiles von West-Borneo' Ibid. vol. xxxiii (1904) p. 369. 



3 ' Over de Geologie van Ambon ' Verhandl. K. Akad. v. Wetensch. Amster- 

 dam, sect. 2, pt. iv, No. 7, 1899 ; & ' Description Geologique de Tiled' Ambon ' 

 Edition francaise du Jaarboek v. h. Mijnwezen in Nederl. Oost-Indie, vol. xxxiv 

 (1905) partie scientifiqne. 



4 Op. cit. 1905, p. 74. 



5 Op. cit. 1905, pp. 73-74. 



