LA TOUCHE : GEOLOGY OF NORTHERN SHAN STATES. 



general elevation gradually falls to the plain in which Hsum-Hsai 

 (Thonze) (C 3) is situated. East of this there is an abrupt rise, 

 crossed by the railway at Kyaukkyan, to the Nawnghkio plateau, 

 which is traversed from north to south by the profound and narrow 

 canyon known as the Gokteik (Shan. Ho Kiit) Gorge. This plateau 

 extends as far east as Pyaung-gaung and Kyauk-me (E 2), beyond 

 which there is a gradual descent, flanked both to the north and 

 south by high ground, to the valley of the Nam-Tu (Burm., Myitnge) 

 at Hsipaw (F 2). South and east of this place the country is 

 very hilly, but beyond these hills again a plateau extends from the 

 Nam-Tu to the lofty peaks of Mong Tung in the south-east, to 

 Loi Ling (8,771 feet, the highest mountain on the plateau) (Plate 1) 

 and the ranges bordering the Salween on the east, and, with some 

 breaks, to the north-east beyond Lashio. 



Practically the whole of the area that may be called ' plateau ' 



is occupied by one formation, a dolomitic 

 Rock formation. ,. , f -n i • ■ i ■« i 



limestone of Palaeozoic age, which will be more 



fully described hereafter, and it is to the peculiar form of disin- 

 tegration which this rock has undergone that the main features of 

 the plateau are due. 



To the north the plateau is bounded by a tract of exceedingly 

 hilly country, in which the rocks are entirely 

 Boundaries of the 0 f pre-Devonian age. The boundary is very 

 plateau. irregular. Starting from Maymyo, which it 



approaches very closely, it turns abruptly north to Kalagwe (C 2), 

 on the road to the Ruby Mmes, from which point it runs south-east, 

 to the head of the Gokteik gorge. From here it runs north in zig- 

 zag fashion till the Namhsim is reached beyond Pyaung-gaung (E 3), 

 and then, crossing this river and the Nam-Tu above Hsipaw, it 

 extends, parallel to the latter river, for an unknown distance 

 to the north-east. The boundaries of the eastern portion of the 

 plateau, in the ne'ghbourhood of Lashio, are not so well defined, 

 for in this direction the limestones are thrown into more or less 

 regular folds, and, in association with the older palaeozoics, form high 

 ranges of hills. Even here, however, whenever the limestones 

 cover any large stretch of country, they have a tendency to form 

 broad undulating expanses, recalling all the features of the main 

 plateau. 



