SILURIAN SYSTEM : LOWER NAMHSIM STAGE. 



129 



La and Ping-hsai, and may be collected on the path from this 

 place to Man-Shio, just above the village of Pangsam (Loc. 67, 

 H 4). 



About a mile south by east of Ping-hsai, in the gorge of the 

 ., ,_ _ southern branch of the Nam-Hen (Loc. 68, 



East side of Loi Pan. tt rx it. i i 



i± o), graptolites occur m large numbers, 



but under a different aspect, for the beds in which they 



are found here are highly carbonaceous, sandy shales, similar 



to those on the Nam-pang-yun, with lenticular bands of coaly 



stuff ; they occupy the same position with regard to the 



purple beds, however, as at other localities, and according to Miss 



Elles, the fossils are a characteristic assemblage from the upper 



part of the zone of Orthograptus vesiculosus, that is to say, are 



almost of the same age as those of Panghsa-pye. They include, 



besides 0. vesiculosus, Monograptus tenuis Portl., M. cyphus var. 



Lapw., M. concinnus Lapw., Diplograptus (Mesograptus) modestus 



Lapw., D. (Glyptograptus) cf. persculptus Salter, Climacograptm 



rectangularis McCoy, and CI. medius Tornq. No other fossils were 



found associated with these graptolites. 



One other graptolite locality may be mentioned here, for though 



it undoubtedly belongs to a somewhat higher 

 Nam-Ha valley. , . * \. ' ... , ° 



horizon, its stratigrapnical position, so tar as 

 can be seen, corresponds to that of the Panghsa-pye band. It is 

 exposed in a cutting on the path from Mong-Ha to Nawa, in the 

 valley of the Nam-Ha among the hills east of Mong-Yai, close 

 to the village of Kanlun (Loc. 69, I 3). Two species of grap- 

 tolite were found here, Monograptus priodon, the well-known Wen- 

 lock form, and a species of Cyrtograptus, which is also a distinc- 

 tively upper Silurian genus. Only one exposure of these beds was 

 met with, and their exact horizon cannot yet be determined. 



Lower Namhsim Stage. 



When the survey of the Shan plateau was taken up in the year 

 1899, the first portion to be traversed was 

 na] reports. immediately adjacent to the railway, 



then in course of construction, and the cart 

 road from Mandalay to Lashio, and it so happened that the form 

 ation now to be described is not passed through by either of these 

 works, while time did not admit of excursions being made to places 



