98 RESEARCH IN CHINA. 
is so slender and round that it suggests the tube of Hyolithellus [Walcott, 18914, 
plate 79, fig. 1a, Tenth Ann. Rept. U. S. Geol. Survey]. 
Formation and Locality.—Middle Cambrian: (C71) Massive cliff-making lime- 
stone in the central portion of the Ki-chéu 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-chéu formation [idem, pp. 139 and 
145 (third list of fossils)], 4 miles (6.4 km.) east of Fang-lan-chén; both in Shan-si, 
China. 
Collected by Eliot Blackwelder. 
Also (35n), Middle Cambrian: Fu-chéu series; limestones near the base of 
the series just above the white quartzite [see Blackwelder, 1907), 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. xxrx, 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 O. daulis [p. 94] except that 
the dorsal face is much broader, which gives a rounded, subtriangular outline to 
the section, resembling in this respect O. 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: (C56) Lower part of Ch’au-mi- 
tién limestone, 25 feet (7.5 m.) below the top of Pagoda Hill [Blackwelder, 19074, p. 
42 (part of last list of fossils)], 1 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, 4a-c. 
Cyrtoceras cambria WaLcorrT, 1905, Proc. U.S. Nat. Mus., vol. Xxx, p.22. (Described and 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 1 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 adepthof2mm. 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, 
