PEI-T'AI PLAIN IN SIBERIA. IOI 



This description gives definite information regarding the occurrence 

 of a peneplain which is clearly older than the Tertiary deposits which cover 

 it, and may fairly be correlated with the Pe'i-t'ai plain. 



With reference to the mountains which lie north of the Amur between 

 longitude 120 and 140 east, and which are known as the Aldan or Stanovoi 

 range, Suess quotes Krapotkin as saying, "That the supposed continuous 

 chain of the Stanovoi range, serving to divide the waters of the Arctic ocean 

 from those of the Pacific, does not exist, whether one thinks of it as high 

 or low, abrupt or flattened."* 



And again, referring to the Vitim plateau, which is north of the ranges 

 of Trans-Baikalia, between 1 10 and 120, he quotes Krapotkin to the effect 

 that over a great distance the country has lost all individuality. 



The travelers who have there sought to follow the line dividing the two slopes have 

 not discovered a long and continuous mountain chain, but have found, on the contrary, 

 virgin forest, rocks covered with moss, and vast swamps interrupted here and there by 

 lakes. 



The region thus described is connected by a long slope with the plain 

 of the Amur, and descends on the northwest to the great plateau of horizon- 

 tal Paleozoic rocks in which the I/ena has sunk its modern canyon. There 

 can be little doubt that the vast expanse of plateau and plain in northern 

 Siberia, from the range of the Verkojansk mountains on the east to the 

 recent alluvium of the Ob on the west, is a great peneplain like that of the 

 Canadian highlands of North America; and traced as it is by the unbiased 

 observations of Krapotkin, Ivanov, and other observers, to a position 

 beneath the Tertiaries of the Amur basin, it may well be assigned to an 

 early Tertiary and Cretaceous epoch. 



I have seen the representative of this peneplain in the vicinity of Kras- 

 noyarsk, where it forms the summit of the hills that bound the valley of the 

 Jenissei', and observed it in the foothills of the northern Altai as far as 

 Irkutsk. From the railroad train one can see the long line of the old topo- 

 graphic surface rising higher and higher in the mountains toward the south, 

 and an observer familiar with the features and interpretation of the Appa- 

 lachian mountains can not doubt that he has here in northern Asia a warped 

 peneplain, which, like the Schooley peneplain, is somewhat extensively 

 dissected. 



The preceding observations may all of them be said to be marginal to 

 the great highlands of central Asia, and although the Pei'-t'ai surface lies 

 at an altitude of 10,000 feet, 3,000 meters, it may be considered a daring 

 proposition to extend an inference regarding the peneplain to the highest 



* La Face de la Terre, vol. HI, p. 145 



