oof, IWOWN & HERON: GEOLOGY AM) ORE DEPOSITS OP TAVOY 



one,— the sea. and wo know that granite reappears again in the string 

 of islands which fringe the coast. The eastern or interior edge of 

 the so-called belt is an arbitrary one. and it is merely giving a very 

 doubtful hostage to the future, to assert that profitable deposits 

 will never be found beyond the Siani frontier in the north of the 

 district or east of the Ban chaung further south. These are the 

 limits of exploration at the present time. The Tavoy field owes 

 its shape to the situation and trend of the great granite masses which 

 form so large a part of it, and wherever similar granite intrusions 

 occiir outside its present boundaries, there is a, reasonable possibi- 

 lity of finding wolfram and cassiterite veins, provided that the por- 

 tions of the parent rock which contained them originally have not 

 been removed. The general distribution as it appears to-day is 

 best appreciated by studying the geological map of the district, 

 with reference to the locations of the larger mines. We consider 

 it better to advise this course than to attempt any limitations in 

 figures, for just as deposits may, and do, occur outside the belts 

 which have becm so described, for example the concessions of the Pe- 

 Palauk-Pyicha region, or to go further afield, the cassiterite deposits 

 of Lampi or Sullivan's Island, so it is equally easy to demarcate 

 large tracts within such belts themselves, where careful search has 

 failed to reveal any minerals of value, and regarding which there are 

 strong reasons for thinking that they cannot occur. 



The general strike trend of the granite is north and south or north- 

 north-west and south -south-east approximately, and along the 

 intrusions where marginal and crest aureoles exist and are favourable, 

 mineral deposits of various kinds are found. The linear arrangement 

 which has given rise to the belt hypothesis is due to this cause. As 

 examples of it we mention the Medaw Kambay, Kanbauk, Taung- 

 shun-taung, Pachaung, Kechaung and Egani mines, associated with 

 the Coastal Range and extending 40 miles from north to south : 

 and the Hermyingyi, Taungpila, Thingandon. Wagon. Putletto, 

 Paungdaw districts stretching '20 miles from north to south as the 

 crow flies, associated with the Central intrusion. It is excep- 

 tional to find any large part of the field where some such arrangement 

 of this kind is not apparent. It is not asserted that any particular 

 vein or vein system carries right through from one mine into the next, 

 indeed this is very often known not to be the case: all we wish to 

 emphasize is that the main vein strike approximates very closely to 

 the trend of the granite masses. 



