ORDOVICIAN SYSTEM : LOWER NAUNGKANGYI STAGE. 



69 



Orthis calligramma Dalman 



,, (Dalmanclla) testudinaria Dalman 



( ,, ) elegantula Dalman 

 ,, ( ? ) chaungzonensis Reed 



,, (Dinorthis) fiabellulum Sowerby 

 „ irravadica Reed 



subcrateroides Reed 

 Chtambonites cf. pyron Eichwald 



,, cf. squamata Pahlen 



Pcrambonites intercedens Pander 



Arthropoda : — 



Calymene birmanica Reed 



Incertay sedis : — 



Cijclocrinus cf. Spasski Eichwald 



The great variation in the lithological character of the rocks at 

 the different localities from which the fos- 



in^sepTrafe outcropf**" sus nave Deen collected, and the fact that 

 in many cases, particular forms have only 

 been found in one locality, renders it extremely difficult to trace 

 any connection between the occurrences at one place or another. 

 Thus at Sedaw (Loc. 88, B 5), where all the Cystideans described 

 by Dr. Bather were obtained, the fossils are found weathering 

 out as hard limestone nodules from a thick band of papery shales, 

 which have been met with nowhere else ; but where the railway 

 crosses the strike of these beds, above the fourth Reversing station 

 at the head of the sharp ascent from Sedaw to the Zebingyi plateau 

 the only rocks seen are hard thin-bedded grey and reddish lime- 

 stones, in which only the faintest traces of fossils have been detec- 

 ted. Nothing like the papery shales in the ravine below is to be 

 seen either to the north or south of the Sedaw valley. It wil) be 

 necessary therefore to describe each outcrop, where collections of 

 fossils have been made, separately, and only to attempt to cor- 

 relate them with each other when such a course seems to be justified 

 by a similarity in the fauna. 



The beds at Sedaw in which the Cystideans mentioned above 

 Fossils Seda occur may be reached by taking a path, which 



leads up the left hank of the Sedaw river ironi 



