Reports & Proceedings — Geological Society of Glasgow. 381 



Gastropods and thirteen Pelecypods : the latter embrace a new 

 Dosiniform shell belonging to the genus Sinodia, the relationships of 

 which are entirely confined to the Indian Ocean regions of Southern 

 Asia. Eighteen of the species, or about 80 per cent, trace their 

 origin from the Vindobonian stage of the Miocene ; ten, or about 

 40 per cent, may be regarded as extinct ; whereas twelve, or 

 50 per cent, still exist in recent seas. The majority of the species 

 are fairly evenly distributed in both the Coralline and the Red Crag 

 formations of East Anglia, although, on account of so large a number 

 being extinct, and bearing in mind their southern facies, it is thought 

 that the rock must be of older age than Red Crag. Additional 

 support is given to this view because such shells as Arcoperna sericea, 

 Tellina benedeni, and Panopcea menardi are not known of later age in 

 this country than the Coralline Crag. The occurrence also of the 

 extinct Gastropods Streptochetus sexcostatus and Ficus [Pyrula] 

 simplex, which are particularly characteristic of the Upper Miocene 

 or Messinian deposits of Northern Germany, constitutes further 

 evidence in favour of a greater antiquity for this limestone than 

 that of the Red Crag : it is therefore considered to be of Coralline 

 Crag age. 



3. "The Origin of the Tin-ore Deposits of the Kinta District, 

 Perak (Federated Malay States)." By William Richard Jones, 

 B.Sc, E.G.S. 



Certain tin-ore-bearing clays and boulder-clays occurring in 

 the Kinta District have been described by Mr. J. B. Scrivenor, 

 Government Geologist E.M.S., as being of glacial origin, and the 

 tin-ore which they contain as having been derived from " some mass 

 of tin-bearing granite and rocks altered by it, distinct from and older 

 than the Mesozoic Granite " (that is, than the granite now in situ in 

 the Kinta District). These clays and boulder-clays are stated to 

 have furnished a more valuable horizon on climatic evidence than can 

 be afforded by limited collections of fossils in rocks far removed from 

 Europe, and have been correlated with the Talchirs of India and 

 mapped as Older Gondwana rocks. 



It would be difficult to over-estimate the importance of the origin 

 of these clays in a country where, on the one hand, they yield a very 

 important part of the world's output of tin-ore, and where, on the 

 other, they have been used as the horizon on which to base the 

 geological age of rocks which cover about a third of the surface of 

 the Malay Peninsula. If of glacial origin, a vast tin-field remains to 

 be discovered. 



The object of this paper is to show that all the tin-ore found in 

 these clays is derived from rocks now in situ in the Kinta District ; 

 that it is not necessary to bring in glacial action to explain any of 

 the features which led to the adoption of the theory of their glacial 

 origin ; to point out that these deposits cannot be correlated with the 

 Talchirs of India ; and to show that a simple interpretation may be 

 given to the geology of the Kinta District. 



The sources of the tin-ore here are: (1) the stanniferous granite 

 of the Main Range and of the Kledang Range ; (2) other granite 

 outcrops known to carry cassiterite ; (3) the granitic intrusions in 



