R. B. Newton — Geology of the Malay Peninmfa. 131 



accentuated by pressure at right angles to them. These slates rest 

 on a basin in granite, and by a movement of this rock they have 

 been highly tilted, so that the average dip is about 80°. The 

 underlie here is westward, while nearer the dividing range of the 

 Peninsula it is eastward. The dip changes along a line about 

 ij^ miles westward from here. The strike of the slates is extremely 

 regular, and is parallel to the main dividing range, or 8° to 81° west 

 of the magnetic north. The mass of slate rock is penetrated by 

 numerous intrusions, which consist generally of granite or green- 

 stones. All the known mineral deposits of any value in Pahang 

 are either included in these intersecting rocks, or occur in close 

 proximity to them. The intrusions generally take the form of large 

 lenticular masses, which are often some miles in width. The 

 main axis of these masses is always parallel to the strike of the 

 slates, and the intrusive rocks sometimes show a cleavage produced 

 by side pressure, parallel to the cleavage of the slates. 



" These intrusions are highly developed in some parts of the 

 country. There is a granite intrusion 1^ miles to the westward 

 of the Tui. This is succeeded to the eastward by a belt of slate 

 about a mile in width, and then we have a belt of intrusive rock 

 about a mile in width, and it is on this that the Tui flows. 



"Overlying all these rocks, and resting on their upturned edges, 

 is a deposit of crystalline limestone, which was originally very 

 extensive, and of great thickness. It certainly has been some 

 thousand feet thick, and there is some evidence which seems to 

 show that it has overlain even the tops of the main dividing range. 

 But only a few isolated patches of this limestone now remain, 

 the rest having been eaten away by the comparatively rapid action 

 of denudation. The limestone in which we are mining is a small 

 patch which remains in the bottom of an ancient valley. Tradition 

 indicates that the Chinese have exported much gold from this part 

 of Pahang, and there is good reason to believe that most of this 

 gold has been derived from the limestone, and has been left on the 

 surface when that rock has been dissolved away. I feel fairly 

 certain that such has been the origin of practically all the gold 

 exported from the Tui valley. 



"The clay deposit was composed of fine yellow clay, which 

 contained some spherical nodules of iron oxide, and rarely some 

 fragments of quartz. The gold was not distributed through the 

 mass, but occurred in occasional streaks or veins, which could not be 

 distinguished by the eye 



" This clay deposit, which covers the whole of the limestone in 

 the valley to a depth of about twenty feet, is the product of 

 decomposition of the greenstone which forms the sides of the valley, 

 and the peroxide of iron nodules which accompany it had their 

 source in the hornblende of that rock." 



Kkmarks.— From the foregoing notices it would appear that the 

 Malay Peninsula is largely composed of plutonic rocks more or less 

 covered by sedimentary strata, of which sandstone, slates, and 



