SINO-MONGOLIAN FRONTIER 



was very noticeable. Working south-east from 

 Pao-te Chou, we shortly encountered limestone, 

 belonging to the Ki-ch'ou formation, the strata of 

 which dipped gently to the west. Rising steadily 

 up through this, we reached a high ridge of lime- 

 stone, descending from which we again reached 

 the sandstone of the Shansi formation, in which 

 the town of K'o-lan Chou is situated, and which 

 extends eastward from here to the Fen Ho. Though 

 we had crossed the great ridge dividing the basin 

 of the Fen Ho from the Yellow River, we did not 

 encounter any of the usual archaic formations. 

 This then forms one of the few breaks in the con- 

 tinuity of the archaic ridge, which runs from Ning- 

 wu Fu to Yung-ning Chow in Western Shansi. 



From K'o-lan Chou we journeyed northward 

 to Wu-tsai Hsien, crossing a low ridge in the 

 Shansi formation, and from Wu-tsai eastward to 

 Ning-wu Fu, crossing a somewhat higher ridge 

 in the same formation. Here we noticed bitumi- 

 nous coal being mined close to the city. North- 

 ward from Ning-wu Fu I noticed the Shansi 

 formation extending for some distance, but I 

 did not pursue my investigation very far in this 

 direction. 



Leaving Ning-wu Fu we journeyed eastward, 

 soon encountering the Sinian limestone, followed by 

 limestone of the Hu-t'o series, originally described 

 from close to this very region by Bailey Willis. 

 A little to the west of T'ai-niu-tien, the limestone 



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