MANDALAY-LASHIO RAILWAY TRAVERSE. 



335 



vation than at the lower locality. They rest upon a bed of hard 

 limestone weathering into a sandy marl, in which the pygidia of 

 Phacops shanensis Reed and casts of Orthoceras are common, but 

 the latter are reduced to dust and are not worth collecting. 



A blank space of two or three hundred yards follows, succeeded 

 by a steep rise to the plateau on which Thon- 



Pymtha flexure. daung stands. The line works along the 

 northern end of this rise, overlooking the Sedaw gorge, through 

 a series of cuttings in more or less flaggy limestones belonging to 

 the Nyaungbaw stage. Fossils are not common, but an occasional 

 crinoid stem or Orthoceras may be found. Camarocrinus asiaticus 

 should occur here, but it has not been found in the railway cut- 

 tings, though it may be obtained in large numbers on the strike 

 of these beds above Yemeye (Loc. 71, B 5), a few miles to the 

 south, where the cart road ascends this rise on the way to Pyin- 

 tha. The rocks form a dip-slope facing west, but at the northern 

 end they bend over into the Sedaw gorge, and the railway runs 

 along the crest of an anticlinal fold. 



An interesting section is exposed immediately beyond Thon- 

 daung (Waboye) station (Loc. 42, B 5). On 



(fJ^p^O) 10 ™ 1 '™ 118 the station P latform shaly limestones belonging 

 to the Nyaungbaw stage are seen, dipping 

 east at about 20 degrees. These are followed, just outside the 

 station yard, by the Zebingyi Tentaculites beds, succeeded in turn 

 by a poor exposure of the Plateau Limestone. Then there is a 

 blank of about 50 yards, beyond which the flaggy Nyaungbaw 

 limestones appear again in a short deep cutting, brought up by a 

 fault and dipping eastwards at about 50 degrees. At the northern 

 end of the cutting the topmost bands of these limestones are seen 

 to be much eroded, and reddish shales with Tentaculites elegans rest 

 directly upon them (Plate 9), dipping in the same direction, fol- 

 lowed, after an interval of some two or three hundred yards, in which 

 the dip becomes much lower, by Plateau Limestone. Thus the 

 section between the station and the cutting is repeated. When the 

 railway was under construction fine specimens of graptolites, 

 Fossils Tentaculites elegans, and Modiolopsis shanensis 



were to be obtained in the ' borrow pits ' 

 beside the line, but they have now become silted up, and it is 

 not easy to obtain fragments of the rock. A conical hill of 

 limestone overlooking these pits is noteworthy as the site of 



