82 RESEARCH IN CHINA. 
Formation and Locality—Upper Cambrian: (C64) Upper limestone member of 
the Kiu-lung group [Blackwelder, 19074, 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. 
Collected by Eliot Blackwelder. 
Eoorthis kayseri (Walcott). 
Plate 4, Figures 8, 8a—b. 
Orthis (Plectorthis) kayseri WALCOTT, 1905, Proc. U.S. Nat. Mus., vol. xxv, p.266. (Characterized 
as below as a new species. ) 
Eoorthis kayseri (Waucott), 1912, Monogr. U.S. Geol. Survey, vol. 11, p. 782, plate xevui, figs. 6, 6a—b. 
(Copy of the preceding reference.) 
This is a larger shell than Hoorthis linnarssont |p. 83], with which it is associated. 
Its surface is marked by numerous fine, radiating striz, four or five in a distance of 
I mm.; and the inner layers of the shell appear to be minutely punctate. The ven- 
tral valve is more convex than the dorsal, the latter being nearly flat in young shells. 
Nothing is known of the interior except one cast of the pseudo-spondylium of the 
dorsal valve, which is larger in proportion than that of E. linnarssoni. 
The largest ventral valve has a length of 14 mm.; width, 20 mm. 
This species belongs in the group of Eoorthis represented by E. desmopleura 
(Meek) [Walcott, 1912b, plate xcv1, figs. 1, ra-7] and E. linnarssoni [p. 83]. 
The species is named after Dr. Emanuel Kayser. 
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; also (C68), upper part of the Ch’au-mi-tién limestone [idem, p. 36 
(part of third list of fossils)], on crest of ridge east of Ch’au-mi-tién, 200 yards (183 m.) 
north of the wayside shrine, Ch’ang-hia district, Shan-tung, and (C74) a dense blue 
dolomitic limestone at the top of the Ki-chdéu limestones [Willis and Blackwelder, 
1907, pp. 139 and 145 (fifth list of fossils)], 4 miles (6.4 km.) east of Fang-lan-chon, 
Shan-si, China. 
Collected by Eliot Blackwelder. 
Eoorthis kichouensis (Walcott). 
Plate 4, Figure ro. 
Orthis (Plectorthis) kichouensis Wa.cort, 1906, Proc. U. S. Nat. Mus., vol. xxx, p.570. (Described 
as below as a new species.) 
Eoorthis kichouensis (WALcotTT), 1912, Monogr. U. S. Geol. Survey. vol. LI, p. 782, plate LXxxIXx, fig. 5. 
(Copy of the preceding reference.) 
This species is represented by a specimen of the dorsal valve. ‘The outline of 
the shell is transversely rounded subquadrilateral; length, 9 mm.; width, 13 mm.; 
the highest point above the plane of the margin is about 3 mm. above the hinge- 
line; a shallow median sinus begins at the umbo, and gradually widens toward the 
front margin; back of the umbo the shell extends beyond the hinge-line, and then 
recedes to the beak, which apparently is at or a little over the upper edge of a very 
narrow area. 
Surface marked by numerous radiating, rounded ribs, with narrow interspaces, 
seven ribs in a distance of 45 mm.; a few bifurcations of the ribs occur at irregular 
intervals between the apex and the margins. There are no traces of concentric 
strie; if on the shell originally, they have been removed by the wearing off of the 
outer surface. 
