CHAPTER XL 



RHiETIC STAGE. 



At the close of the Permo -Carboniferous period we meet for the first 

 . time with a really important break in the sequence 



quenee" 1 ' 1 ' 410 " " of fossiliferous strata represented in the Shan 

 States. There had been no doubt irregularities 

 in the rate of deposition and in the distribution of the sediments over 

 this region, but hitherto they appear to have been of a more or less 

 local character, due to minor changes in the relative positions of land 

 and sea ; such, for instance, as that which has been supposed (ante, 

 pp. 1.33, 179) to account for the local development of the Namhsim 

 Sandstones and of the Zebingyi beds. But now we are confronted 

 with a period during which deposition ceased entirely over the whole 

 area dealt with, when it was raised above the sea level and sub- 

 jected to atmospheric denudation. 



This period covers a great part of the Permian and the whole 



Abs nc f T '• °^ '^ as ' no B * ra * a 01 this age having yet 

 been discovered in the Shan States ; but even 

 here there is evidence that the break was not a very wide-spread 

 phenomenon, and that not far off to the north deposition was still 

 going on. For Triassic rocks are known to occur in that direc- 

 tion in Yunnan, and Mr. Coggin Brown has found that in that 

 country the Khaetic or Napeng beds of the Shan States, now to be 

 described, are underlain by a series of red sandstones with coal seams 

 and salt deposits, indicating the existence of a shallow sea in that direc- 

 tion. 



It seems probable that, at the close of the great reef-building 

 period represented by the Plateau Limestone, 



Nature of movement. , . , . , ., 



there was a negative movement, causing the 

 sea to desert this area, and resulting in a relative elevation of the 

 recently formed reefs above the sea level, similar to that which has 

 occurred in recent times in many parts of the Atlantic and Pacific. 

 I need only cite the Fiji Islands, Cuba, and Barbados as instances 

 of such a movement. It does not appear to have caused any dis- 

 location or folding of the rocks, and may have done no more 

 than raise the whole surface to a slight elevation above sea level ; 

 but it was sufficient to bring the limestones, already thoroughly 



