THE ORDOVICIAN CEPHALOPODA 

 OF CENTRAL CHINA 



by 

 C. C. Yii. 



INTRODUCTION 



When I carried on the field work in Hsien-ning-hsien {f^ M- Wf:), gathering 

 many beautiful well-preserved Silurian fossils in May of the year 1928, Messrs C. Li 

 and W. P. Shu had simultaneously made a collection of orthoceracone Nautilids in large 

 numbers from the Ordovician beds at San-shan-yuan (H Uj W-), He-chiao (^ ^), and 

 some other localities of Ch'ung-yang-hsien (^ |# M), distant about sixty li or a little 

 more than twenty miles southwest of Hsien-ning-hsien. Moreover, the Ordovician 

 cephalopods are also found in the regions to the south-west of Pu-chi-hsien (fi iff Wt), 

 and the south-east of Hsien-ning-hsien. The specimens in this collection are mostly of 

 large size, some attaining nearly one meter in length. Nevertheless, their preservation 

 is rarely perfect. In the majority of cases these cephalopods are obtained from the 

 polished slabs of the dark-gray limestone, where the shell has been partly weathered 

 away on one side, while the remaining portion is seldom separable from the rock on the 

 other side; and therefore no trace of the surface markings has been recognized. Thus 

 the determination of these fossils is based entirely on the internal characters. 



During October of the same year, Mr. Shu and I went to northern Hupeh, and 

 in our field work covered the area of I-cheng (f: Jt), Chung-hsiang (gf p), Ching-shan 

 {« Uj). Ching-men (fi] pg) and Nan-chang-hsien (^ ff). In this trip we collected an 

 abundance of delicate fossils from the different geological horizons ranging from Sinian 

 to Jurassic, though the Devonian and the Triassic deposits have not furnished fossils so 

 far. In this collection the Ordovician cephalopods appear to be one of the dominant 

 types. They are very abundant and wide-spread over the region of northern Hupeh. 

 As our journey required haste, the time was not sufficient to enable us to stay long 

 enough at many of the localities to make more extended collections of fossils. 



The specimens brought back to the Institute from the field during these trips 

 amount to a large number. Unfortunately, the palfeontological publications are not 



