DESCRIPTION OF GENERA AND SPECIES. 85 
19074, p. 33 (part of the last list of fossils)], 2 miles (3.2 km.) north-northeast of 
Ch’ang-hia, Shan-tung, China. 
Collected by Eliot Blackwelder. 
Eoorthis sp. undt. (b) (Walcott).! 
Plate 4, Figure 9. 
Eoorthis sp. undt. d (WaLcorr), 1912, Monogr. U.S. Geol. Survey, vol. LI, p. 793, plate LXxXXIXx, fig. 8. 
(Described and discussed as below.) 
A larger shell of this type [see plate Iv, fig. 9] occurs in Shan-si, in the central 
portion of the Ki-chéu formation. It has a length of 6.5 mm. and a width of 
7.5 mm. The surface is marked by numerous radiating ribs, similar to those of 
the shell from Ch’ang-hia, also concentric striae and several ridges resulting from 
interruption of growth. 
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, 
Shan-si, China. 
Collected by Bailey Willis and Eliot Blackwelder. 
Genus HUENELLA Walcott. 
For discussion of the genus Huenella see Monogr. U. S. Geol. Survey, vol. 1, 
1912, p. 805. 
Huenella orientalis (Walcott). 
Plate 4, Figures 14, 14a-. 
Syntrophia orientalis WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxv, p. 292. (Characterized and 
discussed as below as a new species. ) 
Huenella orientalis (WaLCcorTr), 1912, Monogr. U.S. Geol. Survey, p. 808, plate crv, figs. 3,3a-b. (Copy 
of the preceding reference.) 
This species is closely related in form and surface characters to Huenella texana 
(Walcott) [1912b, p. 808, plate cm, figs. 1, ra] and some forms of H. abnormis 
(Walcott) [idem, pp. 805-806, text fig. 13, p. 299, and plate cu, figs. 2, 2a-m]. It 
differs from themin details of surface ribs. On the dorsal valve there are twoor three 
faintly defined, radiating ribs on each side of the median fold, which has obscure 
ribs upon it. Corresponding ribs occur upon the mesial depression of the ventral 
valve and the side slopes adjoining the depression. The material representing it 
is too limited to warrant an identification with any described species. Huenella 
orientalis is the trans-Pacific representative of H. texana (Walcott). 
Formation and Locality—Upper Cambrian: (C64) Upper limestone member 
of the Kiu-lung group [Blackwelder, 1907a, pp. 37 and 42 (first list of fossils), and 
fig. 10 (bed 20), p. 38], 2.7 miles (4.3 km.) southwest of Yen-chuang, Sin-t’ai district, 
Shan-tung, China. 
Genus SYNTROPHIA Hall and Clarke. 
For discussion of the genus Syutrophia see Monogr. U.S. Geol. Survey, vol. 11, 
1912, pp. 798-799. 
Syntrophia orthia Walcott. 
Plate 5, Figures 1, 1a—b. 
Syntrophia orthia WaLcott, 1905, Proc. U. S. Nat. Mus., vol. xxix, pp. 11-12. (Described and dis- 
cussed as a new species essentially as on page 86.) 
Syntrophia orthia WaLcort, 1912, Monogr. U. S. Geol. Survey, vol. Lt, p. 803, plate crv, figs. 4, 4a—b. 
(Copy of the preceding reference. ) 


ISee synonymy for Hoorthis sp. undt. (a), p. 84. 
