BY THE REV. J. E. TENISON-WOODS, F.G.S., F.L.S., &C. 1187 



Instances of this are common at Assam Knmbang, where the 

 surface soil is level, but underneath this thepaleozoic clays are found 

 to be very uneven and lying in ridges on the summits of which 

 there is no tin but with very rich deposits in the valleys between. 



Thaiping Range. 



The range that bounds the plain from the coast has this pecu- 

 liarity, that it sends out at right angles a number of long undulating 

 spurs, gradually decreasing in height and becoming a series of 

 small detached hills. The spurs end sometimes abruptly, and 

 sometimes run out into the plains for four or five miles. They 

 give rise to a sei-ies of long narrow valleys. Near Thaiping the 

 spurs and the valleys are shorter. Eound the sudden termination 

 of the spur on which the Government quarry is situated^ is the 

 rich tin field of Assam Kumbang. It is curious to remark how 

 the tin mines curve round the base of the hill, and also to what a 

 distance they extend from it. The Residency Hill is a detached 

 portion of one of the many short spurs abutting from the main 

 range. There is evidence that they are or they were covered with 

 outliei's of the paleozoic rock, and to this I attribute the richness of 

 the tin fields around Thaiping. 



5. Valley of the Perak River. — Jungle and alluvium prevent any 

 close examination of the geology of this portion of the section. 

 There are detached outliers of the limestone formation and in the 

 valleys near them I should look for rich tin deposits. At Salak, 

 about four miles from Enggor there is a fine valley with tin in it 

 derived from the spur of the range. In this case there are schists 

 and hard slates in the bed of the river where the stream tin is 

 found. 



KiNTA Range. 



This is another granite mountain chain which is detached from 

 the main axis and trending south. Its exact height is not well 

 known. Those portions which I have seen were overlaid by lime- 

 stone strata, crystalline but with a clear easterly dip of about 17 

 degrees. This rock bore a strong resemblance to the Devonian 

 limestones of North-eastern Australia. These are also crystalline 

 77 



