56 C0GG1N BROWN : MINKS & MINEHAL RESOURCES OF YUNNAN. 



province, thanks to the brilliant researches of the official geologists 



of Tongking. 



A few exposures of the Dinantian, the lowest division of the 

 Carboniferous have been found by Deprat in the Yang-tze valley 

 north of Yunnan Fu. 



The Moscovian or Middle Carboniferous attains an exceptional 

 development and is at least 1,200 metres thick. The lower horizons 

 are sandy, whilst the higher horizons are invariably limestones. 

 Between the two, there is a sandy coal-bearing series with subordi- 

 nate limestone bands. 



During the Uralian, Axtinskian and Middle Permian periods, 

 enormous thicknesses of limestone were laid down during a slow 

 submergence of the sea. In appearance they are so much alike 

 that it is quite impossible to distinguish them lithologically, but 

 the beauty and variety of their foraminiferal remains have enabled 

 this to be done by Deprat and his colleagues. 



These immense limestone masses have made the scenery of 

 Eastern Yunnan what it is. The folded middle Carboniferous 

 of the regions of the great lakes, owing to the ease with which its 

 sandy horizons are denuded, produces great limestone escarpments 

 on the hillsides or forms the fine lines of the crests. The Uralian 

 and Permian limestones constitute a series some 1.500 metres thick 

 without any other rocks. 



At the end of the Middle Permian or perhaps during Upper 

 Permian times a retrogressive 7 movement Set in. The land emerged 

 from the sea and denudation vigorously attacked the limestones, 

 removing them more or less completely according to local circum- 

 stances. 



(8) The Upper Permian or Red Beds Series. 



(a) Western Yunnan. — The elevation and subsequent denuda- 

 tion of the deposits of the Permo-Carboniferous Sea resulted in the 

 formation of a great arenaceous and argillaceous system, not 

 unlike certain facies of the Indian Gondwanas in lithological aspect. 

 A thick conglomerate often separates them from the underlying 

 limestones, and the lower sandstones and shales are characterised 

 by thick beds of rock Salt and gypsum. Red and greyish-red sand- 

 stones, often in thick bands, reddish-purple and greenish shales, are 

 the commoner types of the series which forms a distinct and very 

 monotonous type of country well Seen on the main road between 



