BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



VOL. 13, PP. 127-138, PLS. 16-21 MARCH 30, 1902 



ORIGIN AND DISTRIBUTION OF THE LOESS IN NORTHERN 

 CHINA AND CENTRAL ASIA 



BY G. FREDERICK WRIGHT 



{Read before the Society January 1, 1902.) 



CONTENTS 



Page 



Introduction 127 



Present activity of erosive agencies 128 



Loess on the border of the plain of Peking 129 



Loess west of the first mountain range '. 131 



Loess west of the second mountain range 131 



Gravel bank near Hanoor 133 



Absence of glacial evidence in region northwest of Kalgan 134 



Wind and water combined as distributing agencies 134 



Confirmatory facts from Turkestan 135 



Other evidences of recent geological changes in the region 135 



Additional confirmatory evidence 138 



Introduction 



In the third edition of Professor Geikie's " Great Ice Age," published 

 in 1894, he expresses the opinion, on page 699, that the materials of the 

 loess in Asia " are largely of fluvio-glacial origin, and represent in great 

 measure the flood loams swept down from the mountains and plateaus 

 when they supported vast snow fields and glaciers;" and, in accord- 

 ance with this theory, extensive areas in eastern Mongolia, in Trans- 

 baikalia, and in central Turkestan are marked on his glacial map of 

 Asia as having been covered with ice during the Glacial period. My 

 recent trip across Asia, in company with Frederick B. Wright, was largely 

 directed by the desire to obtain more definite evidence on this point than 

 could be found in any published reports. We accordingly went to 

 Peking, and from there traveled on muleback 150 miles directly west 

 to Kalgan, thus crossing a typical portion of the loess-covered area in 

 northern China. From Kalgan, which lies at the base of the eastern 

 mountain border of the Mongolian plateau, which is here about 5,000 



XIX— Bull. Geol. Soc. Am., Vol. 13, 1901 (127) 



