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COGGIN BROWN : MINES & MINERAL RESOURCES OF YUNNAN. 



PART III 



COAL. 



Coals of three distinct geological ages arc found in Yunnan, 

 belonging to the late Tertiary, Trias or Rhsstic and Carboniferous 



periods respectively. 



Tertiary Lignite. 



Lake basins filled with lacustrine and fluvio-lacustrine deposits 

 of late Pliocene and recent ages abound throughout Yunnan. To 

 these deposits I have given the name "Nan Tien Series." Bands 

 of impure carbonaceous shale and lignite very often occur in them 

 and are mined sometimes for local domestic purposes. 



A typical occurrence is that of the Nan Tien plain (lat. 24° 



49', long. 98°22') which extends for some 

 [ignite of Nan Tien. 15 ' miles (lmvn tne K . m , Ti valley between 



Bhamo and Teng-yiieh. Well-marked terraces, about 80 or 90 

 feet high, border the plain on both sides of the river and are deeply 

 dissected where small tributary streams cross them. Sections of 

 the deposits show them to be made of beds of sand loosely held 

 together, pebble beds which, being slightly cemented, have the 

 appearance of conglomerates, silts, and bluish clays with bands 

 of carbonaceous shale containing fragments of lignite. About half 

 a mile to the east of Nan Tien itself, a band of black carbonaceous 

 shale, about 12 inches thick, crops out in a high terrace of these 

 Tertiary deposits, composed of hard blue clays and white and 

 yellowish sands. In the next valley to the north there arc two 

 outcrops of the same sort of material both about 15 inches thick 

 ;111( | separated by 20 feet of yellowish sands. The outcrop of 

 one of the bands can be traced for 300 yards. The material com- 

 posing the scams is not a true coal, but a carbonaceous shale which 

 has been formed by the addition of much vegetable matter to the 

 mud of a lake or slowly flowing river. It decomposes very easily 

 and goes to pieces when dried, or on exposure to the air for any 

 length of time. In places it is purer, and masses of Lignite, evidently 

 formed from fragments of driftwood, occur in it. 



