74 



who found them characteristic of Upper Ordovician. About the locahty, 

 Abendanon wrote the following lines : 



" Between the Mi-tan and Niu-kan-ma-fei or Ox-liver gorges, we find the 

 Sin-tan area. In about the middle of this area, which is bordered on the W., S. 

 and E. by the high gorge limestone (Wu-shan limestone) mountains, occurs the 

 low and sharp fold of Lung-tchoe. . . . This fold which has a 45° W.- 

 dipping and a 10° E. -dipping limb, itself dips steeply south. It exposes a 

 reddish brown limestone, in which I found lower Silurian Nautili, and many 

 fine and very large Orthoceratite casts. I therefore believe that this must be 

 the same limestone as the Ki-sin-ling limestone of Blackweldek and Willis. 

 On this limestone rests the green shale formation (Sin-tan shale) and above 

 that the gorge limestone formation.^' 



Although the fossiliferous rock exposed along the Yang-tse-kiang 

 (reddish brown limestone) and that of Pan-tse-ya and Kao-huang-ling 

 (brownish marl and dark grey marly limestone) are not lithologically identical, 

 yet it is very probable that they are of the same stratigraphical 

 horizon, for among a few fossils found from these places there are two 

 important forms cominon to them, Orthoccras cJiiuoisc FooRD and 

 Cyrtoccras [JMcloccras) asiaticiiui Yabe. If this be true, then the fossil 

 bed of Abendanon does not correspond to the Ki-sin-ling limestone of 

 Willis and Blackwelder, as suspected by Ai.endanon, but is at most 

 equivalent to the transition beds between the Ki-sin-ling limestone and 

 the Sin-tan shale. In this connection it may be mentioned that the fossil 

 fauna of Sii-kia-pa found in the transition beds contains Triplccia poloi 

 Martelli, which is also known from Kao-huang-ling. 



Thus at present there is no convicing evidence to show that any of the 

 Ordovician faunas mentioned in the preceding chapter were found in the 

 thick Ki-sin-ling limestone itself ; most likely they were derived from the 

 transition beds of Willis and Blackwelder, that is the lower part of the 

 Upper Clayslate series of Noda. The Sin-tan shale then may be not much 

 younger than Ordovician. 



i) Abendanon: I.e. p. 602. 



