Vol. 1. Sun— Cambrian J^aunas of North China (iv) 25 



The associated interior of a pedicle valve (Fig. 13 b. ) shows the cardinal area, 

 muscular impression and the fracturing and the deflection of the striations along the 

 margin of the interior of the valve. 



This species is characterized by a long hinge line, a subquadrate form, and the 

 rounded ribs with i or 5 fine ones between. 



Measurements : — 



Pedicle valve Interior of the pedicle valve 

 Le ngth 13.5mm. 1 3 . ( ) m m . 



Widtli 14.5 mm. 14.5 mm. 



Horizon AND Locality: — Upper Cambrian: from the Shaokuot'un limestone of 

 Ohin-Hsi-Hsien, Fengtien; collected by Dr. J. G. Andersson. 



Eoorthis sp. indt. 



Of this species only a broken specimen was found in the purple shale of the 

 Chang-shan group. It is marked by transverse form, distinct round ribs with In'oad 

 interspaces, four ribs occupying a space of 2.5 mm. near the frontal margin. 



Horizon AND Locality: — Early Upper Cambrian- from purple shale of Chang- 

 shan group of the Kaiping Basin. Associated with this are Changshania coriica, and 

 CliaagsJiania? trancala: Collected by Dr. F. F. Mathieu and Y. C. Sun. 



Genus SynTROPHIA Hall and Clarke 

 Syntrophia orthia Walcott 



Plate 1, Figs. 14a-14b. 

 1913 Syntrophia orthia Walcott, Research in China. Vol. III. p. 85, pi. 5, figs. 1, la, lb. 



Dr. Walcott described and figured the external shell of both valves of this spe- 

 cies. His full description is as follows: — 



''General form irregularly oval with the ventral view obtusely angular toward 

 the apex; rounded, Inconvex, with a deep mesial sinus on the ventral and a strong 

 median fold on the anterior half of the dorsal valves. 



