16 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



The generic reference of this specimen is doubtful, but in the 

 absence of the outer shell it is not possible to determine the generic 

 relations. 



Formation and locality. — Upper Cambrian, lower portion of Chao 

 Mi Tien formation; Pagoda Hill, 1 mile west-southwest of Tai An Fu, 

 Shangtung, China. 



Collected ])y Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



STENOTHECA RUGOSA CHINENSIS, new variety. 



In its general form this shell is closely related to Stenotheca ragosa; 

 it is, however, more elevated and more broadly oval in outline than 

 the typical forms of .5'. rugosa. The surface is marked by a lunnber 

 of moderate undulations, or low concentric ridges, and numerous verj' 

 fine concentric strige of growth ; with a strong lens fine radiating striae 

 are visible. The t^^pe and only specimen in the collection has a longer 

 diameter at the aperture of about 10 mm., with a height of 7 mm. to 

 where the apex is decorticated; at this point the oval section has a 

 length of 2.5 mm., with a width of 1.5 mm. The apex is broken off at 

 a smooth, slightly convex septum. 



This specimen is of unusual interest, owing to the presence of a 

 septum toward the apex. In form it resembles most closelj aS. rugosa 

 acutlcosta, Walcott, but differs from that variety in the presence of 

 rounded instead of acute costs?. From S. rugosa it differs in being 

 elevated and more or less conical. 



Formation and locality. — Lower Cambrian, Man To formation, in a 

 hard, blue-gray limestone, 2.5 miles southwest of Yen Chuang, Hsin 

 Tai, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



STENOTHECA RUGOSA ORIENTALIS, new variety. 



This variety is founded upon a small, slender shell with a rounded, 

 oval aperture. In form it is between Stenotheca rugosa acutlcosta and 

 S. rugosa erecta, being slender, slightly arched, and cornucopia-like. 

 Surface marked by strong, sharply angular concentric ridges, with 

 broader U-shaped furrows between them, and numerous line con- 

 centric stria?. The average length of the shells of this species is 

 3 mm., with a diameter at the aperture of 1.5 to 1.75 mm. 



Formation and locality . — Middle Cambrian, upper portion of Chang 

 Hsia formation ; at Chang Hsia and 1 mile east of Chang Hsia, Shang- 

 tung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



