GEOLOGY. 



199 



past Tavoy and Mergui through the Isthmus of Kra into the Malay 

 Peninsula. In the north the Coastal Range and the Frontier Range 

 widen and join together in a transverse- running mountain mass, 

 where the Tavoy and Amherst Districts and Siani meet. This is 

 crossed by the Moulmein-Tavoy telegraph line over a pass about 

 300 feet high, used only by pedestrians, cattle and elephants. From 

 the headwaters of the Tavoy River a thin sheet of Mergui sedi- 

 mentaries extends to the summit, covering the granite, but it is 

 essentially a granite ridge. 



In the south the district boundary runs up a transverse ridge 

 to the summit of Myinmoletkat (6,800 feet) and down to the Tenas- 

 serim River. This portion of country is little known geologically, 

 but the Myinmoletkat group of peaks is in all probability granite. 

 At all events here also the Tavoy District is cut off from outside 

 communications by mountains, except for a narrow coastal strip 

 three miles wide. The natural obstacles which isolate the district 

 and form its boundaries on every side have doubtless had much 

 to do with developing those special peculiarities which are said to 

 distinguish the Tavoyan from other Burmans ; they actually mark 

 at least the limits of the Tavoyan dialect. 



i Not only is the district surrounded by granite ranges but all 

 the higher land within it is occupied by granite ; excluding the 

 south it is almost correct to say that all land over about 3,000 

 feet in height is granite, with occasional sedimentary cappings ; 

 in the south, however, there are tracts of considerable elevation 

 covered by sedimentaries of the Mergui Series, with doubtless 

 granite underlying a little depth beneath, and indeed sometimes 

 exposed in deep valleys cut down through the sedimentary 

 covering. 



It may be assumed that the granite intrusions have a more or 

 less dome or wedge shaped upper surface, elongated in the direc- 

 tion of the trend of the mountain ranges or axes along which folding 

 has taken place. According to the extent to which denudation 

 has proceeded we may have the granite quite concealed by the 

 overlying sedimentaries, or seen only where the dome has been 

 deeply trenched, we may have the granite extensively exposed 

 and dissected by mountain torrents, but with here and there patches 

 of sedimentaries preserved and giving an idea of the height to which 

 its upper limit rose, or it may be that all the overlying rocks and a 

 great thickness of tho granite itself have been removed. 



