78 LA TOUCHE : GEOLOGY OF NORTHERN SHAN STATES. 



Ordovician of Niti, 1 and is apparently allied to Ptilodictya dichotoma 

 Portl. 



The Diplotrypa, as preserved here, at Tawmawgon, and other 

 places, shows merely the cast of the basal epitheca, the upper part 

 of the fossil being entirely weathered away, and represented by a 

 cavity in the rock. It is one of the commonest fossils in these 

 beds, and occurs in nearly every outcrop. Plectambonites quinque- 

 costata is a form recorded from the Ordovician of Britain, Russia, 

 and Australia, and is allied to Leptcena himalensis Salter, from the 

 Ordovician of Niti. 2 It also occurs at Ledet. 



On the road from Maymyo railway station to the waterworks 

 , , reservoir, among the hills immediately north 



Hills north of Maymyo. , ,, ° . J , 



oi the town, there are several exposures of 

 these beds, but they are not very fossiliferous. and the specimens 

 are greatly crushed, owing to the proximity of a fault along the 

 southern edge of the hills. The only species from this locality 

 (Loc. 92, C 4), that Mr. Cowper Reed was able to identify, is 

 Ofthis flabelluhim Sowerby. Another outcrop occurs in the same hills 

 on the path from Naungkangyi to Taungmio (Loc. 91, C 4) to the east 

 of the reservoir in the Naungkangyi valley, where Diplotrypa (?) sp., 

 Rafinesquina imbrex Pander, and Orthis calligramma Dalman were ob- 

 tained. At both these localities the rocks are sofa, yellow or buff- 

 coloured, fine-grained marls, greatly crushed and cleaved. The lower 

 Naungkangyi beds were not found at any locality to the south of 

 the railway. 



The unweathered limestones associated with the lower Naung- 

 kangyi beds have not, as a rule, yielded any 



Associated limestones. , , • ., , _ . 



recognisable lossils, but are eromposed of an 

 aggregate of somewhat coarsely crystalline grains of calcite and 

 detached stem joints and ossicles of crinoids, or more probably of 

 cystideans, which are visible in great numbers in thin sections of 

 the rock, and sometimes on the natural surface (Plate 11, fig. 1). Their 

 coarsely crystalline character, the absence of dolomite, and the pre- 

 sence of these ossicles serve to distinguish them from the younger 

 limestones of the plateau, which rule much more fine- 



grained, are commonly dolomitic, and very rarely contain any traces 

 of organic remains whatever. 



1 Palseonfc. Niti, p. 46, PI. I V. figs. Hi, 17. 



2 Ibid, p. 28, PI. Ill, fig. 4a— q. 



