20 | GUNONG TAHAN AND GUNONG RIAM. 
about the same time, which I have called the Main Range Anti- 
cline, and the Benom Anticline. As these arches were formed, much 
of the rock fell into the molten granite, but when the latter consoli- 
dated, stratified rocks remained above. Much later in the earth’s 
history denudation laid bare the granite cores below the remains of 
these anticlines, carving out the main range and the Benom range. 
In time denudation will cut down into these granite masses. How 
far have they cut down already ? 
It is obvious that at some period of the process of denudation 
the highest peaks would show remains of the superincumbent 
stratified rocks. At such a time a large part of the surface of the 
granite core would be visibie In the case of the main range there 
is some reason to suppose from the evidence of the distribution of 
tin-deposits that denudation has not gone far beyond this surface 
of the core of granite, and it is very interesting to find, as de 
Morgan noted in the eighties, that the summit of Riam is composed 
of altered stratified rocks, phyllites and quartzite. On this, the 
highest peak of the main range, there is then a remnant of the 
superincumbent stratified rocks, corroborating the other evidence 
“of denudation not having advanced far into the granite mass. I 
~ expect too that stratified rocks will be found on Gunong Gyang, on 
Yang Blav, and other high peaks in the neighbourhood. We may 
regard these rocks on Riam as a remnant of the lid of the 
Peninsula’’ which, when removed, revealed the vast wealth of 
tin-ore below. 
Riam, then preserves for us a portion of this lid. Lower peaks 
in the main range that I have ascended, Gunong Ulu Kali and Gu- 
nong Berembun, have been stripped of these rocks and show granite 
only, as far as we know. 
Gunong Tahan however, and the Tahan range generally, although 
connected with this folding, fall into a different category. A glance 
at the map shows that the Benom Anticline lies parallel to the 
Main Range Anticline. Between the two anticlines the east limb 
of the latter and the west limb of the former meet, and when they 
meet we find a range of hills formed of quartzite and conglomerate. 
These rocks are the younger members of the two arches, and we ex- 
pect to find them of course on the east side of Benom as part of the 
east limb of the Benom Anticline. They are there, forming a great 
belt of hilly cotintry stricking through the centre of Pahang and 
including the Tahan range, which is on the western border of this 
belt. 
The Tahan range, then, including Gunong Tahan, is part of 
one of the two great arches. 
Gunong Riam is capped by a small remnant of the other of 
the two arches, but is chiefly composed of granite. 
Gunong Ulu Kali, Berembun, and the majority of the peaks 
in the main range, as far as we know, retain no trace of the arch, 
but consist of the solid granite core only. 
Jour. Straits Branch 
