2o6 



M. H. LOVEMAN 



correlations. The area described here helps to explain these dif- 

 ferences and assists in correlating the two sections. Owing to 

 the strictly economic purpose of our work in the field no attempt to 

 gather fossils was made, and consequently the mapping was done 

 on strictly lithological grounds. The various formations have, 

 however, with the exception of the Ordovician and Silurian beds, 

 such definite lithological characteristics that their determination 

 can be safely made without recourse to fossils. The Ordovician- 

 Silurian beds are not mapped separately but are shown as a single 

 formation between the known older slates and quartzites and the 

 younger Devonian- Carboniferous limestone. 



TABLE I 



List of Formations 



Period 



Recent \ 

 Subrecentj ' ' 



Tertiary 



Jurassic 



Permian 

 Carboniferous 

 Devonian 

 Silurian 1 

 Ordovician/ ' ' 



Ordovician 1, 

 Cambrian?/ " 

 Cambrian . . . 

 Arcliean 



Igneous 



Name in the Northern Shan States and Character 



Alluvium — old river terraces — travertine 



Clays — sandrock and brown coal 



Nam Yau series — red sandstones with limestone beds 



Plateau limestone — not differentiated into an upper 

 and lower as by La Touche because of lack of fossil 

 evidence 



Namhsim, Naungkangyi, and other Silurian and 

 Ordovician beds of La Touche grouped because of 

 lack of fossil evidence, shales, sandstones, and some 

 limestone beds 



Pangyun beds — not mapped by La Touche. Sand- 

 stones, shales, and occasional limestone beds 



Chaung Magyi — quartzites and shales 



Mogok gneiss with limestone bands 1 



Granite — intrusive into gneiss and Chaung Magyi] 

 but age unknown. Basic dikes — intrusive intoj 

 the granite 



Yunnan Equivalent 



Nan Tien series 



Permo-Carboniferous and older 

 Paleozoic limestones 



Pu-Piao series 



Possible transition beds be- 

 tween Kao-liang and Pu-Piao 



Kao-liang series 



Crystalline series. Gneiss, 

 granite and mica schist with 

 a few limestone bands of 

 Brown 



In Table I are given the formations present in the area discussed. 

 The same names are assigned to them as are used by La Touche in 

 his Geology of the Northern Shan States. In the right-hand column 

 are given what appear to be the corresponding formations in 

 Yunnan. The names are those given by J. Coggin Brown in his 

 reports on that province. 



TOPOGRAPHY 



The main structural features are the high mountain region of 

 the western section (some of the peaks being over 7,000 ft.) com- 

 posed of granite, gneiss, and the older Paleozoic sediments, and the 



