GO LA TOUCHE : GEOLOGY OF NORTHERN SHAN STATES. 



Upper Xaungkangvi Stage. 

 Lower Xaungkangvi Stage. 

 (Ngwetaung Sandstones.) 



As will be explained below in dealing with each formation, this 

 sequence is not universally present, the members of it enclosed in 

 brackets being extremely local in occurrence, while there is a very 

 close connection between the upper Xaungkangvi beds and the 

 purple shales of Hwe Mawng. In fact it is only for convenience 

 of description, since they occur in widely separated areas, and it 

 is not yet certain how far they are mutually equivalent, that 

 different names are now given to them. 



Ngwetaung Sandstones. 



These beds consist of coarse to fine-grained brown sandstones 

 usuallv with a somewhat calcareous matrix 

 teretnd^cuiibution 0 ' and sometimes enclosing thin lenticular bands 

 of limestone, forming the crest and western 

 slopes of the high range of hills culminating in the peak of Xgwe- 

 taung (3.403 ft. B 5), which rises boldly from the foot-hills due 

 east of Mandalav, and is distinctly visible from that place. These 

 sandstones, so far as has been ascertained, contain no characteristic 

 fossils, the only remains found in them being scattered fragments 

 of crinoid stems, and a few very ill-preserved 

 Fo " specimens of a small Orthis (0. testudinaria 



Dalman). They are separated off from the more fossiliferous beds 

 overlying them because they seem to be of extremely local develop- 

 ment, and because none of the characteristic fossils of the higher 

 beds, with the exception of the doubtful Orthis mentioned above, 

 have been found in them. To the west they are cut off by a 

 fault, the rocks forming the western side of the longitudinal valley 

 separating Xgwetaung from the foot-hills being Devonian limestones. 

 They may perhaps appear a little further east, on the eastern side 

 of the Kyet-maok valley above Taunggaung. being brought up by 

 a parallel fault, but no fossils were found in them here, and it 

 was found impossible, owing to the want of clear sections, to separ- 

 ate thorn distinctly from the underlying Chaung-Magyi rocks. They 

 have not been found iti any other locality at the base of the fos- 

 siliferous series, though they may perhaps be represented on the 

 southern scopes of the Loi-len range to the east of Lashio, where 



