BY THE REV. J. E. TENISON-WOODS, F.G.S., F.L.S., (fcc. 1183 



8. Alluvium of the Kinta Valley. 



9. A low limestone range of crystalline limestone in which a dip 

 and strike may be observed. 



10. Alluvial valley. 



11. Central granite chain. 



I shall now proceed to consider the geology of these eleven 

 formations. 



1. Alluvial Mangrove Flats. — These are a sei-ies of mud islands 

 and flats from two to three miles in width, fringing the whole of 

 the coast line. The vegetation is principally made up of Rhizophorae. 

 There can be no doubt that such islands and flats are the usual 

 deposits from lands on which great erosion is going on, from 

 numerous and large rivers and an abundant rainfall. They point 

 very clearly also to an absence of any upheaval along the coast 

 line. Like the eastward of Australia in its northern and central 

 portions the waste Irom the land is gradually extending the limits 

 of the shore and filling up the sea. Such a process has been going 

 on for a very long geological period in the Straits of Malacca. 

 Both the coasts of Sumatra and Malaysia prove this as well as the 

 shallowness of the Strait and the numerous mud banks occurring 

 in it. The rich vegetable mould in this formation is entirely due 

 to the mangrove forests, valuable as timber for fuel and making a 

 very graceful and luxuriant fringe to the shores. I intend subse- 

 quently to make a report on the general aspect of the vegetation of 

 tha mangrove flats. It is extremely probable that here they cover 

 tin deposits, but the great depth and the water must render them 

 inaccessible. 



1. Quaternary Drifts. — Probably most of the surface drifts in 

 this State are quaternary, but I restrict the term now to those drifts, 

 which form the alluvial plain between the Mangrove and the 

 Thaiping Range. These range between 10 and 30 feet deep and 

 have all been deposited by the various small streams which now 

 run across the plain. These have been larger and smaller, fewer 

 or more numerous by turns in the history of the filling up of the 

 level. The channels have also shifted to an almost inconceivable 

 extent according as the levels were altered by the deposition of 



