Vol. I. Sun— Cambrian Faunas of North China (iv) 17 



Class BRACHIOPODA Dumeril 



Genus ObOLUS Eichwald 



Obolus (Westonia) leei Sun (sp. nov.) 



Plato I. Fig. 3a-3c. 



Shell of medium size, depressed convex ; general form broadly ovate, almost sub- 

 quadrate, with the pedicle valve obtusely acuminate. The frontal margin nearly straight, 

 both sides are nearly parallel, regularly and gently rounded; posterior margins straight on 

 both sides of the beak, meeting at the latter at an angle of about 125". Shell little 

 longer than the wide. 



Surface marked by coarse concentric lines of growth and the characteristic orna- 

 mentation. This appears to be formed of a very fine network of oblique depressed lines 

 which divide it into minute diamond-shaped spots, a surface which resembles, under a 

 strong lens, the texture of finely woven cloth. 



This species is represented by only one valve of the shell ; the measurements are 

 as follows : 



Length 9.0 mm. 



Width 8.5 mm. 



Horizon and Locality: — Cambrian: from purple shale of Luan-Chou. Collected 

 by Dr. F. F. Mathieu, geologist to the Kailan ^Mining Administration of Tang-Shan. 



This species is named after Prof. J. S. Lee ^Ht^ of the National University. 



The surface-ornamentation of this species is not unlike that of Oholus ( Westonia) 

 stoneanus (Whitfield) from the Upper Cambrian sandstone of Sauk county Wisconsin 

 (U. S. A.) but it differs in the broad form of the shell, and also in size. 



This species is characterized by its subquadrate form and reticulated structure of 

 the surface, which is a feature quite distinct from that of any known Chinese species. 



Obolus mollisonensis? Walcott 



Plate I. Figs. 4a, 4b. 



1912 Obolus mollisonensis Walcott, Cambrian Geology and Pal. (Smiths. Miscell. coll. Vol. 57) Vol. II 



No. 7; p. 1:31, pi. 35, figs. 10-12. 

 1938 Obolus mollisonensis Walcott, Sun. Bull. Geol. Soc. of China. Vol- II No 1-2 p. 94 (listed). 



