Federated Malay States. 513 



age, and on account of this Dr. Aug. Tobler, in his description of the 

 volcanic rocks of South Sumatra in Mi/nwezen, 1912, assigns them to 

 the Permo-Carboniferous period. Thus, in age the Sumatran and 

 Malayan volcanic rocks correspond, for the latter are extensively 

 interstratified with Raub rocks, and certain fossils from limestone 

 beds belonging to the Raub Series give it a Permo-Carboniferous age. 



Volz says that the volcanic rocks of South Sumatra do not persist 

 so late as the Triassic period, and this is a point of difference from 

 the Malayan rocks, for the latter were being deposited during and 

 probably later than the period of formation of the Lower Gondwana 

 beds of Pahang, which are correlated with the uppermost Trias. 



The Tertiary volcanic rocks of the Goemaigebergte seem, from 

 Dr. Gutzwiller's descriptions, to contain no epidote, and this agrees 

 with the rocks of the Malay Peninsula, where rocks younger than 

 the Mesozoic granite contain no epidote. It will be remembered 

 that some specimens of the dark-purple quartz-porphyry of Selangor 

 contain epidote, and that this is taken as evidence of the pre-Granitic 

 age of the intrusion. 



Conclusions. 



It is not possible to define the limits of the volcanic period with 

 any certainty. The majority of the tuffs and lavas are interstratified 

 with Raub shales, and fossil evidence proves that some of them are 

 of Permian age. The field evidence suggests that the Raub shales 

 are contemporaneous with the Raub limestones, and the latter 

 contain fossils of Upper Carboniferous Limestone ( Visean age), but no 

 volcanic rocks have yet been seen that were underlain and overlain 

 by Raub limestones. A boulder-in-tuff deposit was seen in contact 

 with a vertical face of limestone in the river bank a few hundred 

 yards down-stream from Lubok Plang, but according to the theory 

 that the boulders are a beach-deposit it is certain that the deposit is 

 lying unconformably against the limestone. So we have proof that 

 there was volcanic activity during the Permian period (late Raub), 

 and there is no proof that it started so early as the Carboniferous 

 period. 



It is possible that volcanic activity continued during the period of 

 dry land which prevailed through the greater part of the Triassic 

 and perhaps during a part of the Permian period, and we know that 

 tuffs were being deposited at the coming on of the Gondwana shallow- 

 water conditions, when the beach-deposit was formed. 



Tuffs and lavas were extruded during the deposition of the earliest 

 Gondwana rocks in the north and south zone now marked by the 

 Pahang and Tembeling Rivers and probably also further to the east, 

 though this last point has not been investigated. No cases of Pahang 

 Yolcanic Series intrusions penetrating Gondwana rocks have been 

 noticed, though there are several doubtful cases; for instance, the 

 granophyre north of Pulau Guai and the quartz-porphyry at Jeram 

 Gading*. However, if the beach-deposit of boulders in tuff was 

 formed immediately before the earliest Gondwana rocks of the 

 locality it is clear that the granophyre was intruded and laid bare 

 before this date, for granophyre boulders are included in the deposit. 



DECADE VI. — VOL. IV. — NO. XI. 33 



