MANDALAY-LASHIO RAILWAY TRAVERSE. 



337 



be conveniently visited from this station, as it lies only a mile 

 away to the east (Loc. 30, C 4). The outcrop of the fossiliferous 

 band lies just outside the western gate of the village, and the 

 fossils may be picked out in large numbers from the surface clay. 

 Some good examples of calcareous dams may also be seen in the 

 bed of the picturesque Ke-laung stream close by (Plate 19). 



Proceeding onwards from Wetwin the line runs for a consider- 

 able distance over an almost level expanse 



\A otwin to Kvaukkyan. * 



oi the Plateau Limestone, surrounding the 

 town of Hsum Hsai (Thonze). The chief point of interest in 

 this stage of the journey is the extraordinary number of streams 

 that are crossed, all flowing from the hilly ground to the north, 

 and gradually bunching together until they join the Hpawng-Aw, 

 running along the foot of the Kyaukkyan scarp, causing the map of 

 this tract to look like that of a delta reversed (Fig. 11 on next page). 

 Two explanations of this multiplicity of streams have suggested them- 

 selves to me. Either the valley was covered, at no distant period, 

 with a layer of the Napeng shales, which has now been entirely 

 removed by denudation, but at so recent a date that the streams, 

 issuing from numerous springs in the hills to the north, have not 

 yet had time to excavate deep channels in the hard limestone 

 floor. Or, and this seems the more probable explanation, the 

 streams are so choked with travertine that they are unable to 

 deepen their channels ; on the contrary their beds are so quickly 

 filled up with this deposit that they are constantly changing 

 their courses, giving rise to the anastomosing network of channels 

 which we see. There is, it must be said, no evidence that the 

 Napeng shales once extended over the whole of this area, though 

 there are two small mounds, composed of yellow shales, on the 

 railway between Hsum Hsai and the Kyaukkyan scarp, which 

 may belong to this period : but they contain no recognisable fossils. 



We now come to the Kyaukkyan scarp, which has been grow- 

 K aukk an more an( ^ more well defined since we 



left Wetwin. To the south a long line of 

 precipitous cliffs of limestone curtained with thick deposits of traver- 

 tine marks the crest, but at the gap where the railway and cart- 

 road cross it these are not conspicuous. At this point the rise 



takes the form of a uniclinal flexure in the 

 Flexure. ,. 



limestone rather than a fault scarp, and the 



ascent from the valley we have left is only about 400 feet, but 



