DESCRIPTION OF GENERA AND SPECIES. 69 
Formation and Locality—Middle Cambrian: Ch’ang-hia limestone (C1 and 
C2), lower shale member of the Kiu-lung group [Blackwelder, 1907a, pp. 37 and 
40 (part of the third list of fossils), and fig. 10 (beds 4 and 5), p. 38], 2 miles (3.2 km.) 
south of Yen-chuang, and (C6) thin, platy limestone in the upper shale member 
of the Kiu-lung group [idem, pp. 37 and 41 (second list of fossils), and fig. 10 (bed 12), 
p- 38], 2.5 miles (4 km.) southwest of Yen-chuang, Sin-t’ai district, Shan-tung, China. 
Collected by Eliot Blackwelder. 
Obolus (Westonia) sp. undt. Walcott. 
Obolus (Westonia) sp. undt.a WaLcort, 1912, Monogr. U.S. Geol. Survey, vol. LI, p. 468. (Discussed. ) 
Fragments of shell marked with stronger transverse, irregular, sharp ridges 
occur a little higher in the Cambrian section of Shan-tung that clearly indicate 
a species of Westonia distinct from Obolus (Westonia) blackwelderi Walcott. 
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, 19072, p. 
42 (part of last list of fossils)], 1 mile (1.6 km.) west on Tsi-nan, Shan-tung, China. 
Collected by Eliot Blackwelder. 
Genus LINGULELLA Salter. 
For discussion of this genus see Monogr. U. S. Geol. Survey, vol. LI, 1912, 
pp. 468-474. 
Lingulella manchuriensis Walcott. 
Plate 3, Figures 1, 1a-e. 
Lingulella manchuriensis WALCOTT, 1911, Smithsonian Mise. Coll., vol. 57, No. 4, p. 74, plate 14, figs. 
2and 2a. (Described and discussed as a new species essentially as below.) 
This species and Lingulella marcia belong to a group of small, elongate, oval 
shells that are represented in the Rocky Mountain Province Cambrian fauna by 
Lingulella manticula (White) [Walcott, 1912b, plate xx, figs. 1, 1a—c], and the Atlantic 
Province fauna by L. atava (Matthew) [Walcott, 1912b, plate xxxv, figs. 5, 5a—h], 
L. collicia (Matthew) [Walcott, 1912), plate xxxv, figs. 1, 1a—e], L. ferruginea Salter 
[Walcott, 1912b, plate xxrx, figs. 1, 1a—-w, 2, 2a-f, and plate xxxv, figs. 4, 4a-b], 
L. nanno (Walcott) [1912b, plate xxrv, figs. 1, ra—d], and a number of similar forms 
illustrated on plates xx1 and xxxv of Monograph u1, U. S. Geological Survey. 
L. manchuriensis appears to be most nearly related to L. similis (Walcott) [1912b, 
plate xx1, figs. 2, 2a~-j, 3, 3a—d]. It differsin the broader, more rounded posterior 
half of the ventral valve. 
The average length of the ventral valve is 3 mm. among the large number of 
shells that occur in both limestone and shale. 
Formation and Locality.—Middle Cambrian: (35p) Fu-chéu series; shales about 
80 feet (24 m.) 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. 
Lingulella marcia Walcott. 
Plate 2, Figures 6, 6a-f. 
Lingulella marcia Watcott, 1911, Smithsonian Misc. Coll., vol. 57, No. 4, pp. 74-75, plate 14, figs. 
3 and 3a. (Described and discussed as a new species essentially as below.) 
This species is one of the small forms allied to the group of similar shells 
mentioned under L. manchuriensis. It differs from the latter species in being 
