98 RESEARCH IN CHINA. 



is so slender and round that it suggests the tube of Hyolithcllus [Walcott, 18910, 

 plate 79, fig. 10, Tenth Ann. Kept. U. S. Geol. Survey]. 



Formation and Locality. Middle Cambrian: (071) Massive cliff-making lime- 

 stone in the central portion of the Ki-chou formation [Willis and Blackwelder, 1907, 

 pp. 139 and 145 (second list of fossils)], 4 miles (6.4 km.) southwest of Tung-yii; 

 and (C72), thin green gray limestone interbedded with ocherous and green clay 

 shales, overlying the massive oolite in the Ki-chou formation [idem, pp. 139 and 

 145 (third list of fossils)], 4 miles (6.4 km.) east of Fang-lan-chon ; both in Shan-si, 

 China. 



Collected by Eliot Blackwelder. 



Also (35n), Middle Cambrian: Fu-chou series; limestones near the base of 

 the series just above the white quartzite [see Blackwelder, 19076, p. 92, for general 

 section giving stratigraphic relations], collected in a low bluff on the shore of Tschang- 

 hsing-tau Island, east of Niang-niang-kung, Liau-tung, Manchuria, China. 



Collected by J. P. Iddings and Li San. 



Orthotheca sp. undt. Walcott. 



Plate 6, Figure 3. 

 Orthotheca sp. undt. WALCOTT, 1905, Proc. U.S. Nat. Mus., vol. xxix.p. 21. (Characterized as below.) 



Fragments of a small, elongate, slender Orthotheca occur in the Upper Cambrian. 

 The species has a transverse section much like that of 0. daulis [p. 94] except that 

 the dorsal face is much broader, which gives a rounded, subtriangular outline to 

 the section, resembling in this respect 0. cyrene [p. 93], but the latter has a shallow 

 groove on the dorsal face which is absent in the fragments under consideration. 



Formation and Locality. Upper Cambrian: (O'ofi) Lower part of Ch'au-mi- 

 tien limestone, 25 feet (7.5 m.) below the top of Pagoda Hill [Blackwelder, 19070, p. 

 42 (part of last list of fossils)], i mile (1.6 km.) west of Tsi-nan, Shan-tung, China. 



Collected by Eliot Blackwelder and Li San. 



CEPHALOPODA. 



Genus CYRTOCERAS Goldfuss. 



Cyrtoceras cambria Walcott. 



Plate 6, Figures 4, 4<j-r. 



Cyrloceras cambria WALCOTT, 1905, Proc. U.S. Nat. Mus., vol. xxix, p. 22. (Described aud discussed 

 as a new species essentially as below.) 



Shell gently curved, laterally compressed. Section ovate, dorso-ventral diam- 

 eter as compared with the lateral diameter toward the last chamber being nearly 

 as 4 to 3, the greatest lateral diameter being nearer the dorsal than the ventral side; 

 dorsal side more obtusely rounded than the ventral. Septa arching slightly for- 

 ward from the dorsal side; short, about five in a distance of 2.5 mm. where the 

 shell has a diameter of from i to 1.5 mm. Chamber of habitation supposed to be 

 of moderate depth ; none of the specimens clearly shows the margin of the aperture. 



This species is represented by a number of more or less fragmentary specimens. 

 The largest has a dorso-ventral diameter near the aperture of 3 mm., with a length 

 of 7 mm. to where the diameter is 1.25 mm. ; the chamber of habitation appears to 

 have a depth of 2 mm. The siphuncle in a specimen 2.25 mm. in the dorso-ventral 

 diameter has a diameter of less than 0.2 mm.; it is situated on the dorsal side and 

 almost reaches the exterior surface of the thin shell, which is somewhat thickened 

 on the dorsal side. 



