Our course lay in a north-easterly direction up the right bank of the river 

 for about six miles, and the sections exposed were carefully noticed. The 

 strata on the left bank (Shansi side) seem to be chiefly of red-brown and green 

 shales, arranged for the most part in slightly folded beds of varying thickness, 

 dipping slightly to the south-west. Near Wu-pao Hsien, where the caravan 

 effected a crossing, this folding is rather more pronounced than elsewhere. On 

 the right bank the strata are composed of yellow-grey sandstone arranged in 

 horizontal beds, and rise to a height about two hundred feet lower than those 

 on the left. 



After crossing the river, we continued up a deep ravine through strata of 

 green and red-brown shale, finally crossing a ridge upon the summit of which 

 loess to a depth of fifty feet occurs. The descent from the crest is first through 

 loess, and then through shale till a small river-valley is reached. Here the 

 section showed nothing but horizontally stratified shale, and sandstone v ith 

 thick superimposed loess beds. Our road lay up this valley as far as Yung- 

 ning Chou where the granite and gneisses, which occur in the Chiao-ch'6ng 

 district, again appear. Working east from Yung-ning, we approached 

 Wu-ch'6ng, a large village situated about twenty miles distant, and again 

 encountered the Sinian limestone, dipping in a north-westerly direction at a 

 slight angle. On crossing a divide we descended into a deep ravine cutting 

 through the limestone, which extends to within ten miles of F6n-chou Fu. 

 Here the strata are perfectly horizontal, as shown in the accompanying 

 photograph (Plate 58), which also gives a good idea of the depth of the limestone 

 beds. Between the end of these beds, which form a surface free from loess, 

 and the valley of the F6n Ho, the ordinary Shansi coal-bearing series occur 

 covered by a thick deposit of Huang-t'u formation. The latter comprises here 

 both loess, and Shao-fu. 



The road from F6n-chou Fu to T'ai-yiian Fu has been traversed by several 

 geologists, so that I will not presume to offer any remarks about it. 



The Huang-fu Formation. 



One of the most characteristic features of the provinces of Chihli, Shansi, 

 Shensi, and Kansu is afforded by the vast Aeolian deposits, commonly called 

 the " Chinese Loess." This has also received the name of " the Huang-t'u 

 Formation," and is divisible into two classes : — 



(i) That which is purely wind-deposited, and may be called Loess. 



(2) That deposited by rivers in the form of great plains, such as those 

 of Pao-ting Fu and T'ai-yiian Fu, and conveniently termed Fluvial Loess, 



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