448 E. S. Willboum — The Pahang Volcanic Series — 



or less extent in Singapore* 1 Island, 2 Job ore *, Negri Sembilan*, 

 Selangor *, and Perak *, and possibly also in the more northern states, 

 Kedah*, Kelantan*, and Trengganu *. The present account deals 

 for the most part with the main development in Pahang, and most 

 of the information was obtained on two trips, one to examine the 

 railway-cuttings from Gem as* to Kuala Lipis, and the other to 

 examine outcrops over a distance of about 100 miles in the rivers 

 Jelai and Pahang, from Kuala Lipis to Mengkarak. 



A large part of the first trip was fruitless, for the railway cuttings 

 over a distance of 80 miles in Negri Sembilan * and part of Pahang 

 were so much weathered that they conveyed practically no information. 

 For instance, it was impossible to determine whether certain sandy 

 strata intercalated with shales near Kerdau railway-station were 

 weathered quartzites or volcanic-tuffs, and it is possible that the 

 Gondwana outcrop extends further to the north than is represented 

 on the map, whereas, on the other hand, it may be incorrect to leave 

 the 20 miles of river and railway below Kuala Tekal barren of 

 Pahang Volcanic Series rocks, and indeed, in the sketch-map attached 

 to the above memoir, Mr. Scrivenor indicated their presence along 

 this stretch. Between Kuala Krau and Kuala Lipis, and particularly 

 along that part between Kuala Tekal and Kuala Lipis, there were 

 some excellent exposures, but at the time when the trip down the 

 Pavers Jelai and Pahang was taken the river was not low, and so 

 many exposures which had previously been described by Mr. Scrivenor 

 were not seen on this occasion. 



Great use has been made of the information and specimens collected 

 by Mr. Scrivenor from different rivers and from the Benta-Kuantan 

 road, and the occurrences of Pahang Volcanic Series rocks represented 

 on the Map (Plate XXX 3 ) in all districts, excepting the railway and 

 Pi vers Jelai and Pahang, have been copied from bis 1911 sketch-map. 4 



Associated Rocks. 



The Pahang Volcanic Series is associated with the sedimentary 

 rocks of the llaub, and also, to a less degree, with Gondwana rocks. 

 The Raub Series is the more prominent in the Pahang Valley, and 

 consists of limestones and calcareous shales, the colour of the lime- 

 stones varying from white to black, according to the quantity of 

 carbon they contain. The greater part of the Gondwana rocks is 

 made up of quartzites, grits, and shales, the exposures of quartzite 

 being usually weathered to sandstone except in fresh cuttings, though 

 occasionally "core-boulders" of hard quartzite are found. In many 

 parts of the Peninsula cherts are seen at the base of the Gondwana 

 rocks, and in Negri Sembilan * several exposures east of the Main 



1 An asterisk marks the names of all those places in Malaya mentioned 

 in the text which are outside the area shown on the accompanying Map, 

 Plate XXX. 



2 Described by Mr. Scrivenor in the Geol. Mag., Dec. V, Vol. VI, 

 pp. 17-22, January, 1909. 



3 The Map will appear in the second part of the paper in November. 



4 The photographs of rock-sections illustrating this paper (Plate XXIX) 

 were taken by Mr. Scrivenor, to whom I now tender my best thanks. 



