IV. 



THE GEOLOGY OF THE TAHAN RANGE. 



By J. B. SCRIVENOR, 

 Geologist, F.M.S 



r "PHE following Account of the Geology of the Tahan Eange is 



based chiefly on notes collected during an ascent of Gunong 

 Tahan in May, 1906, and subsequent journeys in Pahang : 



The Tahan Range is remarkable in being composed almost entirely, 

 as far as is known, of a series of estuarine rocks — comprising shale, 

 sandstone, grit and conglomerate — which is provisionally named 

 the Tembeling Series. The main range of the Peninsula, which, 

 although greatly more extensive in length, rises very little higher than 

 Gunong Tahan, is believed to be all granite and its modifications, but 

 for occasional areas of schistose rocks, representing altered sediments. 



Two ranges, similar to the Tahan Range, but on a smaller scale, 

 are known in the Federated Malay States. One of these is a long 

 range of low hills in the west of Pahang, parallel to the main range, 

 and referred to elsewhere as the Bentong-Telom Range ; the other is 

 the small isolated Semanggol Range forming the border between 

 Larut and Krian in Perak. 



No direct evidence of the age of this series of estuarine rocks has 

 yet been derived from the Tembeling District of Pahang ; but fossils 

 discovered elsewhere point to a range in time dating from the Rhsetic 

 to the Inferior Oolite. The collections made, however, are not 

 numerous, either in specimens or species. 



The breadth of the outcrop of the Tembeling Series in the typical 

 district is about thirty-five miles. The strike is roughly N.N.W.-S.S.E., 

 and there is reason to suppose that the series extends into Johore, 

 reappearing as far south as Singapore. The Tahan Range lies on the 

 western side of the outcrop. It would appear that the Tembeling 

 River, whose general course in the upper reaches is to the west, has 

 been turned south by this enormous barrier. 



On either side this outcrop of the Tembeling Series is flanked by a 

 wide outcrop of a series of calcareous rocks and associated igneous 

 rocks, named provisionally the Raub Series and the Pahang Volcanic 

 Series, respectively. One of the remarkable ranges of limestone hills 

 belonging to the Raub Series was seen from the top of Gunong Tahan 

 and visited later by the writer. It lies to the west of the range and is 

 situated near Ka in pong Cherual in the Ulu of the Tanum, a left tribu- 

 tary of the Jelai. From a peak in this limestone range a magnificent 

 view of the Tahan Range, about fifteen miles distant, was obtained ; 

 and it appeared to the writer that it would be easier to ascend Gunong 

 Tahan from this side than from the east. 



