CHAPTER X 

 GEOLOGICAL NOTES 



GEOLOGICALLY the country traversed on 

 the various journeys described in this book 

 may be divided into two sections, separated 

 roughly one from the other by the outer loop of 

 the Great Wall. 



South of this line, in Chihli and Shansi, the 

 outcrops are chiefly of sedimentary rocks, with here 

 and there masses of the underlying plutonic and 

 metamorphic rocks showing through. Thanks 

 to Baron von Richthofen and Bailey Willis these 

 rocks are pretty well understood, and there re- 

 mains only the work of recording their occurrence 

 in different localities, and any other geological 

 phenomena hitherto unobserved. These stratified 

 rocks extend westward and northward across the 

 Ordos, North Shensi and well into Kansu, and 

 also up to the extreme north-west of Shansi. 



North of the outer loop of the Wall the outcrops 

 are entirely igneous and metamorphic, granite, 

 trachyte, basalt, porphyry, gneiss and schist 

 occurring in great confusion, so that considerable 



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