68 



CHAPTER III. 



Geology of the District along the Middle Course 



of the Yang-tse-kiang. 



The district lying along the middle course (I-chang to Kui-chou) of the 

 Yang-tse-kiang has invited attention of many geologists of different nationali- 

 ties ; the stratigraphy of the rocks exposed there is variously interpreted by 

 them, and there prevails a great diversity of opinion on certain important 

 points. 



According to Willis and Klackwelder, the Ki-sin-ling limestone, 

 already referred to above, is the representative of the Cambro-Ordovician 

 Sinian formation in the said district.^^ They found no fossils in the hmestone 

 in situ ; but based on the fossils {Oboliis asiatica) found in the pebbles picked 

 up on a river bar of the Nan-kiang,-' near Chon-ping-hsien,"- prov. Shen-si, 

 they believed the lower part of the limestone to be almost equivalent to the 

 basal part of the Kiu-lung group of Shan-tung. The upper part of the Ki- 

 sin-ling limestone shows, on the other hand, a transition to overlying Sin-tan 

 shale, the transitional beds being composed of interbedded shale, and 

 limestone, and yielding the Middle Ordovician fossils at Su-kia-pu, as stated 

 above. 



" In the transition with the underlying Ki-sin-Mng (Sinian) limestone, the 

 shale (Sin-tan shale) lies directly upon an even and unweathered surface of 

 the limestone as if in conformable relation. Where the limestone lies over- 

 turned upon the Sin-tan,*^ on the south side of the Ki-sin-hng, the transition 

 between the formations was noted particularly, the layers of shale in- 

 cluding seams of limestone which become more abundant and pass quickly 

 into massive dark limestone with local shaly partings. Wherever observed, 

 the contact with the overlying Wu-shan''' (Carboniferous) limestone presented 



1) Research in China, p. 269. L, i. 



2) Nan-kiang = g?X 



3) Ch6n-ping-hsien = ^2p.^ 



4) Sin-tan = ^i| 



5) Wu-shan = ^tlj 



