TERTIARY. 



317 



attributed to underground denudation of the rocks on which they 

 lie (since in the Lashio coal-field the silts resting on the limestone 

 and on the Namyau sandstones are equally inclined), shows that 

 the period of deposition was anterior to the cessation of orogenic 

 activity in this region, and that the basins in which the silts were 

 accumulated may have resulted from a ' warping ' of the surface, 

 already carved into its present outlines. The volcanic outburst 

 in the Mansang basin, which undoubtedly took place after some 

 of the silts had been deposited, is also an indication that these 

 movements had not ceased at this period, and if this eruption was 

 contemporaneous with that of Hawshuenshan near Tengyueh in 

 Yunnan, it may very well be of Pleistocene age. For v. Loczy 

 has shown 1 that Hawshuenshan was active at the time when the 

 alluvium of the Tengyueh basin, which he thinks was then occupied 

 by a lake, was being deposited. For my own part, I am inclined 

 to think that these lignite-bearing silts of the Shan States should 

 be correlated approximately with the Pleistocene gravels of the 

 Narbada, Tapti, and Godavari rivers in the Indian peninsula which, 

 as Mr. Vredenburg has shown, were accumulated in basins due to 

 ' warping ' of the surface in Pleistocene times. 2 



I am informed by my colleague Mr. Coggin Brown that in 

 Yunnan strata of precisely the same character as those now under 

 description are of common occurrence in the valleys, and that they 

 also contain lignite. The towns of that country are frequently built 

 upon them, and they have all the appearance of sediments filling old 

 hike basins. He also informs me that he has found in them a species 

 of Bijthinia identical with one which is still living in the Erh-hai lake 

 at Ta-li-fu. In the Southern Shan States also Mr. E. J. Jones has 

 described. Ric;>rds G. S. I., Vol. XX, Pt. 4, p. 1907) a bed of lignite, 

 near the shores of the Nyaungwe lake, which he considers to be 

 imbedded in an old lake-deposit similar to that which is now being 

 accumulated not far off in the present lake. 



It is to be hoped that further collections will be made from these 

 interesting beds, and that some more definite 

 me?s nditi ° n <lf SPeCi " Pronouncement as to their age may be possible 

 in the future; but the rocks and the fossils con- 

 tained in them are so friable that it is difficult to preserve them. 

 The ground is everywhere saturated with water, and so soon as the 



1 Rsiso dos (imfon Belli S/cchcnvi in Oslasicn, Vol. 1, p. 772. 



* Pleist.nceno niovumonta in India : Records, Uevl. Sur. hid.. Vol. XXXIII, Ft. 1, p. 13. 



