CHAPTER VII. 



SILURIAN SYSTEM. 



The local names given to the formations in the Northern Shan 

 States belonging to the Silurian system are 

 the following, in descending order : — 

 f Zebingyi beds. 

 Upper Silurian . ■< Upper Namhsim, or Konghsa Marls. 



(_ Lower Namhsim (Sandstones). 

 Llandovery . Panghsa-pye Graptolite band. 

 As in the case of the Ordovician strata, these formations are 

 not always present, one of them, the Zebingyi beds, being of ex- 

 tremely local development. It will be seen in the sequel, also, 

 that there is some doubt as to whether this formation should not 

 be included with the Devonian Plateau Limestone immediately 

 overlying it. 



Llandovery Group. 

 (Panghsa=pye Graptolite Band). 



Immediately above the purple shales at the top of the Upper Naung- 



kangyi beds exposed in the valley of the Nam- 

 Occurrence and char- m , , f , ., , , ■ ■ » , 

 actors. iu > a band of white snales is found, containing 



graptolites in large numbers. This band has not 

 been detected anywhere to the west of Panghsa-pye, an easily accessible 

 village on the Nam-hsan road about eight miles north-west of Hsipaw, 

 though the purple shales have been traced as far as the G-okteik 

 gorge. It is very liable to erosion, however, on account of its 

 soft character, and its outcrop is apt to be concealed by rainwash ; 

 and it is therefore possible that this band may yet be found to 

 occur in that direction. Unfortunately the discovery of the grap- 

 tolites was not made, by Mr. Coggin Brown and myself, until after 

 the country to the west had been traversed, and it has been found 

 impossible to revisit it ; but the horizon at which the graptolite 

 band should occur is so well marked by the purple shales beneath 

 that there should be no difficulty in determining whether it is 

 present or not. 



