CHINA, MONGOLIA, AND JAPAN. 77 



which are characterized by abundant remains of the mammoth as well as of Bos 

 urus and BMnoceros ficJiorJumts. 



We have seen that although the effects of erosion are generally not very extensive 

 in the steppe deposit, they exist in some places on a large scale. The deeply cut 

 valley in the Tamchintala is an instance, and one that seemed to me could have been 

 caused only by fluviatile action. The erosion in the neighborhood of BUika Noor, 

 and the presence in the eroded valleys of loam strongly resembling that deposited 

 by great rivers is another instance. This loam was not often seen, indeed it is 

 mentioned in my notes only as occurring in the Mingan hills, at Bilika Noor, and 

 over the steppe deposit near Goshun. 



The closing event in the history of the great sea that in comparatively recent 

 times covered so large a part of Asia, extending from the pole to the Caspian and 

 Black sea, and from the Ural mountains to near the Great Wall of China, was the 

 disappearance of its waters from the long trough that reaches from the shores of the 

 Arctic sea, through the Barabinsky steppe to the Aralo-Caspian depression. 



It appears to me that the ancient physical geography of this vast region, and the 

 effects of its elevation, present one of the most interesting and important fields of 

 exploration. Whether we consider the meteorological changes that must have been 

 brought about by the upheaval of so large an area, or the influence of this great 

 water communication and its currents on the distribution of existing genera, the 

 geological phenomena that have affected this broad belt of the great continent have, 

 beyond doubt, had an important influence on the recent history of our planet. 



In the following table I have recapitulated the few leading events in the geologi- 

 cal history of China and Mongolia which seem to be recognizable. 



