2 



LA TOUCHE : GEOLOGY OF NORTHERN SHAN STATES. 



land, and he crossed the boundary at only one point, between Ta- 

 li-fu in south-west Yunnan and Bhamo in Upper Burma. In Yunnan 

 he found a series of rocks which, as the following pages will show, 

 correspond very closely with those of the Shan States ; including 

 representatives of the lower Silurian or Ordovician, Middle Devonian 

 and Permo-Carboniferous Systems, succeeded by a series of red beds 

 ranging in age from Permian to Jurassic. And his observations have 

 been so far supplemented by those of the French geologists employed 

 on the survey of the country in advance of the railway which has 

 now been carried up from Tongking, and by those of my colleague 

 Mr. Coggin Brown, — who had the advantage, before he visited 

 Yunnan, of making himself acquainted with the geology of the 

 Northern Shan States, — -that it is possible to correlate, with a certain 

 amount of confidence, the formations in these two areas with each 

 other, and consequently with those of Central China ; and to infer 

 that they were accumulated under similar conditions and in a single 

 sea basin. 



There can be little hesitation, I think, in accepting the asser- 

 tion that the crystalline complex of Archaean 

 Relations with Gond- rocks, on the borders of which these sediments 



wanaland. . , . - . . 



were accumulated, once formed an integral 

 portion of the Gondwana continent, though they are now separated 

 from the Indian Peninsula by a great depression, filled for the 

 most part by Tertiary and recent deposits. The Archaean rocks of 

 the Himalaya, which are now acknowledged to have formed a part 

 of Gond wanaland, 1 are now separated from those of the Peninsula 

 in a precisely similar manner by the broad Indo-Gangetic plains, 

 and I think that there is evidence to show that the separation in 

 each case took place at about the same period (s -e below, p. 351 

 seq.). An account of these depressions, their significance and their 

 cause, has been given by Professor Ed. Suess, 2 who designates 

 them by the name of ' foredeeps ' (voriiefen). 



The references to the Shan States in the geological literature of 

 Burma, before the year 1887, are of a very 



Previous notices. . . . , , , . 



meagre description, and are almost entirely 

 confined to an enumeration of the useful minerals that were sup- 

 posed to occur on the plateau in great abundance. These minerals 

 are always mentioned in the accounts of the embassies that were 



1 H. H. Havden, op. cit., Vol. IV. pp. 221, 227. 



* Das Antlitz dcr Erde, Vol. 1, Chap. XII Vol. Ill, pp. 335, 581. 



