SILURIAN SYSTEM : LLANDOVERY GROUP. 



other, the whole dipping to the south-east at about 30 degrees. 

 The band containing the graptolites consists entirely of fine whito 

 shales, and is of no great thickness, probably not more than 50 

 feet, throughout which the graptolites seem to be fairly evenly 

 distributed. No other fossils were found actually associated with 

 the graptolites, but just below the horizon in which they are most 

 numerous, and a few feet only above the top of the purple beds 

 a stratum of yellow sandy shale occurs crowded with the remains 

 of trilobites of more than one species. The abundance of the 

 remains of individuals in this stratum, although it is not more 

 than six inches thick, is astonishing ; and though they are much 

 broken up, the minutest details of their structure are preserved. 

 Immediately beneath this is a layer of well preserved specimens -of 

 brachiopods, probably including several species, but neither these 

 nor the trilobites have yet been accurately determined. 



The fossils from this locality have not yet been described in 

 detail, but the graptolites have been examined 

 Graptolites. ^y ]yjj gs q. j j< Elles, and are pronounced 



by her to be of undoubted Llandovery age ; in fact, one of them, 

 Diplograptus (Orthograptus) vesiculosus Nich., is one of the zone 

 fossils of the Lower Llandovery, characteristic of the middle divi- 

 sion of the Lower Birkill shales of Southern Scotland. The other 

 graptolites are Diplograptus (Mesograptus) modestus Lapw., Clima- 

 cograptus medius Tornq., C. rectangularis McCoy, and Monograptus 

 tenuis Portl., all of which occur in the zone of 0. vesiculosus in 

 Britain. There are two trilobites in the layer 

 at the base of the graptolite band, a new 

 species of Phacops, allied to Ph. imbricaius Ang., and an Acid- 

 aspis, which is interesting as the only species of this genus that 

 has yet been found in these hills. It is a. small trilobite, and the 

 head shields alone have been found, but it is fairly common. 

 The brachiopods. etc., mentioned in the list given above were also 

 collected at this locality. 



In the valley of the Nam-Tu, north of Panghsa-pye, the grap- 

 ^ tolite band is found in several places, both at 



the base of the scarp to the east of the 

 river, and on the spurs on the west side, at the base of the out- 

 liers of Upper Silurian sandstone which occur above Tapok and 

 Ta-pangtawng ferries. On the east bank graptolites were found on 

 the path to Lilu ferry, about a mile below the crossing (Loc. 59, 



