324 LA TOUCHE : GEOLOGY OF NORTHERN SHAN STATES. 



(Burm. Taung ya), which corresponds to the 'jhuming' of the 

 hill tribes of Assam. Under this system a certain area is cleared 

 of jungle, which is burnt on the spot when dry, and crops, 

 chiefly rice and millet, are grown for three, or perhaps four years 

 in succession, when the land becomes exhausted, mainly by the 

 washing away of its fertile constituents during the rains. After 

 the lapse of several years, when the ground is again covered with 

 scrub jungle, the process is repeated ; and it does not appear to 

 have such evil results on the erosion of the soil as might be 

 supposed, for in the course of a year or so the surface is pro- 

 tected by a covering of coarse grass. The sterility of the soil 

 may be in some measure due to the absence of lime. For 

 though it is derived in great part from the decomposition of the 

 limestone beneath it, analysis shows that it contains no trace of 

 lime, even in close contact with the rock. And I think that it 

 would be well to find out by experiment whether the addition of 

 lime, which might be obtained by burning the rock which crops 

 out in every field, at very little cost, would not tend to its amelior- 

 ation. 1 



The other rocks of which these hills are composed also weather 

 into clays of various colours and composition, 

 Other varieties of protected from erosion in a similar way to 



surface clay. r ... -. • ,v i n 



such an extent, that it is often dimcult to find 

 a single outcrop of solid rock for miles together. The colours and 

 consistency of these clays often give a useful, though rough, guide to 

 the nature of the rock beneath, and I append a list of them :— 



Formation. Colour of surface clay. 



Gneiss and mica schists . . Bright red, often micaceous and sandy. 



(These are the red clays mentioned 

 by Dr. Noetling in his account of the 

 tourmaline mines of Mong Long re- 

 ferred to above). 



Chaung-Magyi Series . . • Variegated, of light colours. White, buff, 



yellow, or pink. 



1 In the year 1907 I submitted a note to the Government of Burma, suggesting that 

 experiments should be undertaken by the Agricultural Department of the Province, with 

 the view of discovering whether the addition of lime to the clays of the Shan Plateau 

 would not increase their fertility. If the productive capacity of the soil could be en- 

 hanced, to even a small extent, it would op->n to permanent settlement many thousands 

 of acres of land now practically barren, in a country possessed of a salubrious climate 

 and an abundant rainfall. But, so far as I am aware, no steps have yet been taken to 

 give effect to this suggestion. 



