G COCHIN BROWN : MINES & MINERAL RESOURCES OF YUNNAN. 



been estimated that they form about one-fifteenth of the total area 

 of the province and support one-third of its population. These 

 plains are nearly all the dried beds of old lakes ; occasionally the 

 lakes or portions of them still exist ; they date b&ck to sub-recent 

 times when the land stood at a higher level than it does now. They 

 are always intensively cultivated and form a striking contrast 

 with the nigged mountains surrounding them. Practically Iho 

 whole of the walled cities are built on such sites at heights of 5,000 

 or 6,000 feet, while the ranges rise 3,000 or 4,000 feet above them. 

 The lowest land in the province is found in the bottom of the 

 deep river canons where they cross the southern frontiers. The 

 Mekong leaves at 1,700 feet, the Red River at 500 feet and the 

 Clear River at 700 feet above the level of the sea. 



CLIMATE. 



It is impossible to advance any general statement regarding 

 the climate of Yunnan which would be applicable to the whole 

 province. Its area is as large as that of some European kingdoms 

 and it possesses a bewildering variety of topographic detail, broad 

 open spaces alternate with exceedingly high mountain ranges, there 

 are regions nourished by some of the greater rivers of the world 

 and there arc others parched and uninhabitable owing to the lack 

 of water. I divide the province into three climatic zones : — 



(a) The Tibetan tract north of the 27th parallel, 



(b) The low plains and deep river valleys, mainly of the south 



and west, 



(c) The central elevated portion. 



As I have no experience of the Tibetan tract I quote the views 

 of Major Davies, " A country of very high mountain ranges the 

 plains even rising to from 8,000 to over 12,000 feet. The climate 

 here is naturally colder than other parts of Yunnan, and where 

 heights extend from 6,000 feet on the river banks to over 15,000 

 feet on the hill tops, it varies much in different places. At the 

 higher altitudes snow may fall in any month of the year, and many 

 of the passes are liable to be blocked throughout April. In the 

 plains the climate is less severe, but except in a shut-in river bed 

 it never becomes hot." (D., p. 309). 



In the low plains and deep river valleys of the south and west, 

 the general elevation is from 3,000 to 4,000 feet with the rivers 



