310 LA TOUCHE : GEOLOGY OP NORTHERN SHAN STATES. 



beds, and seams of brown, lignitic coal, which last are in general 

 the most substantial rocks seen in the few outcrops that occur, and 

 to which the formation owes such importance 



Old Lake basins. . * 



as it possesses. Ihey are found m detached 

 areas occupying the present river valleys, and it is significant 

 that they are confined to the portions of the plateau surrounding 

 the high ground culminating in the lofty peak of Loi Ling, the 

 highest point in the States. These detached basins, in fact, seem 

 to have formed an assemblage, of lakes similar to that of the 

 English Lake District, and were either silted up entirely, or were 

 perhaps drained by the deepening and cutting back of the channels 

 in the limestone through which the rivers in every case now find 

 their exit. 



The economic importance of this formation, due to the presence 



_.. ., of the coal seams, has led to the devotion of 



Distribution. . r . . 



a considerable amount of attention to it, and 



full accounts of each basin, the mode of occurrence of the beds 



and the economic value of the fuel they contain, have appeared 



in the Records of the Geological Survey. 1 The areas in which they 



have hitherto been found are six in number : — 



(i) In the upper part of the Namyau valley, beyond the 

 limits of the map, there is a small patch of these 

 r x rocks, surrounding the village of Mongyaw (Lat. 23° 2', 



Long. 98° 9'), but little is known about them. I search- 

 ed for coal in them in 1900, but without success, nor 

 did the inhabitants seem to be aware of any outcrops. 

 In any case they cover a very small area. This patch 

 is separated from the Lashio coal-field by a broad band 

 of the Namyau sandstones, which crosses the valley 

 from south-west to north-east between Mongyaw and 

 Mongyang, and through which the river flows in a deep gorge. 

 The Lashio coal-field. This basin extends along the 

 Namyau valley from Mongyang westwards to Hsunkwe, 

 a few miles north of Lashio, and is about 15 miles in length, 

 with an average breadth of 4 miles. The river runs along 

 the southern boundary of the field, which is all that 



1 P. Noetlin<:, Coal-Fields in the Northern Shan States; Records, Oed.Surv.Ind., 

 Vol, XXIV, l't. 2, p. !)<) : T. D. La Touche and R. R. Simpson, The Lashio Coal-Field ; 

 Ibid, Vol. XXXIII, Ft 2, p. 117: R. R. Simpson, The Namma, Man-sang, and Man- 

 sole Coal-Fields ; Ibid, p. 125 : P. N. Datta, MS. Report, 1903-04. 



