﻿Vol. 66.~] rtTLATJ TBIN AND PULAU NANAS. 429 



In dealing with areas so large as the Malay Peninsula and 

 Archipelago it would be too much to assume, even were there no 

 evidence to the contrary, that masses of granite far removed from 

 one another are of the same age ; but there is one factor in the 

 geology of the East Indies that supports the correlation of certain 

 granite masses. This is the presence of tin-fields ; and we may 

 suppose, therefore, that the granites of the Peninsula and the 

 islands of Banka and Billiton, 1 which lie approximately on a pro- 

 longation of the axis of the Peninsula, are of the same age. With 

 the exception of some radiolaria found on Billiton and described 

 by Dr. G. J. Hinde as probably Palaeozoic, 2 the two islands have 

 afforded no pakeontological evidence of the age of the granite ; but 

 on the Peninsula the case is different, and we have reason for 

 supposing that the tin-bearing granite is post-Inferior Oolite, 

 and certainly post-Triassic. 3 This gives us one limit of age : for 

 the other we must turn to the Archipelago, where we have the 

 significant fact that in Sumatra and Java are Tertiary deposits con- 

 taining granite pebbles. Thus Dr. Verbeek & Dr. Fennema state 

 that the oldest Tertiary conglomerates of Java contain granite 

 fragments 4 ; and, again, Dr. Yerbeek in 1875 described Tertiary 

 breccias in Central Sumatra 5 containing fragments of syenite, 

 granite, quartz-porphyry, etc. We may say, then, that the other 

 limit is not later than the oldest Tertiary ; but if we go to 

 Borneo, we find further though not such strong evidence. In his 

 description of Central Borneo, 6 Prof. Molengraaff speaks of granite 

 and pegmatite boulders found in great quantities in a conglomerate, 

 probably of Cretaceous age, on the Seberoewang River, and on the 

 •slopes of Mount Oejan, adding, however, that nothing is known of 

 the origin of those boulders. So it is possible that the granite of 

 the Peninsula, and therefore the normal granite of Pulau Ubin, is 

 post-Inferior Oolite and pre-Cretaceous, while it is almost certainly 

 post-Triassic and pre-Eocene. 



I am aware that Dr. Verbeek' s opinion as to the age of the 

 granite of Banka and Billiton was, at the time when he described 



1 See R. D. M. Verbeek, ' Geologische Beschrijving van Bangka & Billiton ' 

 Jaarboek van bet Mijnwezen in Nederl. Oost-Indie, Welensch. Gedeelte, vol. xxvi 

 (1897). 



- See Dr. G. J. Hinde's Appendix to Dr. Verbeek's memoir, ' Note on a 

 Radiolarian Chert from the Island of Billiton ' pp. 223-27 & pi. iii. 



3 R. B. Newton, ' On Marine Triassic Lamellibrnnchs discovered in the 

 Malay Peninsula ' Proc. Malacol. Soc. vol. iv, pt. iii (1900) pp. 130-35 & pi. xii ; 

 'Fossils from Singapore, &c.' Geol. Mag. dee. v, vol. iii (1906) pp. 487-96 

 & pi. xxv ; ' Age & Locality of the Estheriella Shales from the Malay Peninsula ' 

 Rrid. vol. ii (1905) p. 49 ; also T. Rupert Jones. ' A Triassic Estheriella from 

 the Malay Peninsula' Ibid. pp. 50-52 & pi. ii. 



* R. D. M. Verbeek & R. Fennema, ' Description Geologique de Java & 

 Madoura' vol. i (1896) pp. 38 & 39. 



' ' On the Geology of Central Sumatra ' Geol. Mag. dec. ii, vol. ii (1875) 

 p. 479. 



6 'Geological Explorations in Central Borneo (1893-94)' pp. 251-54 & 433. 

 London. 1902. 



