ORDOVICIAN SYSTEM : UPPER NAUNGKANGYI STAGE. 



89 



pleurides sp. and Pliomera ingsangensis, a new form described by 

 Mr. Reed, were found. The Remopleurides is a unique specimen, 

 and is not in a very satisfactory state of preservation, but "most 

 of the characteristic generic features are visible." The Ledet 

 specimen, according to Mr. Reed, is allied to R. Colbii Portlock, 

 from the Caradoc beds of Co. Tyrone in Ireland. Pliomera ing- 

 sangensis is the most common trilobito in the upper Naungkangyi 

 beds, and the detached pygidia occur at a large number of locali- 

 ties ; specimens of the thorax and carapace are not so frequently 

 found. The pygidia are often very minute, and require to be 

 carefully looked for. 



The genus, more commonly known as Amphion, is exclusively 

 Ordovician, and has a wide geographical range, occurring in Bohemia 

 as well as in Russia, Britain, and America. The species described 

 by Mr. Reed resembles in the characters of the head PI. (Plio- 

 merops) canadensis Billings, but the pygidium agrees more closely 

 with PI. Fischeri Eichw., a Baltic species. A pygidium described 

 by Salter 1 from the Ordovician of Niti resembles the Burmese form 

 so closely that Mr. Reed is convinced that they are identical, but 

 he thinks that there is insufficient evidence for attributing this 

 pygidium to the head-shield described by Salter as Cheirurus mitis. 

 for not only are the material in which the head-shields and 

 pygidium occur, and their mode of preservation, quite distinct, 

 but the pygidium is not of a Cheirurus type, no species of that 

 genus being known to possess more than four pairs of pleurae, 

 whereas both the Burmese species and the Niti specimen figured 

 by Salter have five. 



On the path from Maymyo to Naungkangyi village, where it 

 crosses the hills north of the railway station, numerous plates of 

 Caryocrinus sp. were found, also another cystidean, Echinoencrinus 

 cf. angulosus Pander, a Russian form from the ' Vaginatenkalk ' 

 (lower Ordovician) near St. Petersburg. Specimens of Orthis irra- 

 vadica and Pliomera ingsangensis Reed may also be found here, 

 on the slopes of the hills facing Naungkangyi (Loc. 92, C 4). 



To the south of the railway the upper Naungkangyi beds cover 

 a large area in the valley of the Nga-pwe-s6n 

 Ng4-pwe-s6n va Icy. stream, to the east of the ridge bordering the 

 Maymyo cart road between Pyintha and Zegon, extending from 



l Palaeont. Niti, p. 6, pi. I, figs. 18,18a 



