1190 GEOLOGY AND PHYSICAL GEOGRAPHY OF THE STATE OF PERAK; 



from it to the north, so that in reality they are diverging groups 

 distinct from it, and terminating to the southwards. It is owing 

 to these isolated groups that the Malayan Peninsula widens out to 

 so great an extent about the centre of the State of Perak. Looking 

 at the extent to which denudation has taken place, we have clear 

 evidence that the central range has been much higher than it is 

 now, but its reduction has been by erosion, not by subsidence. 

 Much of this has been carried to the sea as sediment, and some 

 spread in the valleys. The upheaval of these large mountain 

 systems is too much involved in obscurity to render any specula- 

 tions on the subject of use in estimating the physical geology of the 

 country. It may, however, be fairly assumed that the granite was 

 at one time overlaid completely by the paleozoic formation, and 

 probably by the limestone. The upheaval dates subsecpiently to the 

 deposition of the latter. The granite has broken through both 

 formations, depositing them, and it may be other newer strata on 

 each side of the chain. Erosion through the countless ages has 

 left us the rocks as they stand at present. 



The granite being a metamorphic rock was pix>bably at one time 

 stratified and was one of the earliest formations, either Lower 

 Cambrian, or Laurentian. This accords with what is universally 

 observed in connection with tin deposits which are always found 

 in the most ancient rocks. The metamorphism must date subse- 

 quently to the deposition of the paleozoic clays and may even 

 have been subsequent to the deposition of the limestone. The 

 breaking through of the granite chain may have been much later. 

 The chronology of the opei-ations thus revealed may be stated thus : 

 1. The tin was originally disseminated in finely divided m3sses in 

 the paleozoic strata, of whatever age they were. 2. It was subse- 

 quently segregated and brought to the surface of the overlying 

 rocks. 3. It was brought within the influence of erosion by the 

 upheaval of the granitic chain. 4. Denudation distributed it as 

 stream tin in the valleys and alluvium. 



There is one more geological question that may here be touched 

 upon. It is generally recognised in the present day that in granite 

 we have one of the results of volcanic action presented to us. It 



