82 RESEARCH IN CHINA. 



Formation and Locality. Upper Cambrian: (C64) Upper limestone member of 

 the Kiu-lung group [Blackwelder, 19070, 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-i. 



Urthis (Plectorthis) kayseri WALCOTT, 1905, Proc. U.S.Nat. Mus., vol. xxvm, p. 266. (Characterized 



as below as a new species.) 

 Eoorthis kayseri (WALCOTTl, 1912, Monogr. U.S. Geol. Survey, vol. LI, p. 782, plate xcvn, figs. 6, 6a-b. 



(Copy of the preceding reference.) 



This is a larger shell than Eoorthis linnarssoni [p. 83], with which it is associated. 

 Its surface is marked by numerous fine, radiating stria?, 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. desmo pleura 

 (Meek) [Walcott, 19126, plate xcvi, figs, i, ia-r] and E. linnarssoni [p. 83]. 



The species is named after Dr. Emanucl Kayser. 



Formation and Locality. Upper Cambrian: (Cfi4) Upper limestone member of 

 the Kiu-lung group [Blackwelder, 19070, 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 (('(18), upper part of the Ch'au-mi-tien limestone [idem, p. 36 

 (part of third list of fossils)] , on crest of ridge east of Ch'au-mi-tien, 200 yards ( 1 83 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-chou 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 10. 



Orthis (Plectorthis) kichouensis WALCOTT, 1906, Proc. U. S. Nat. Mus., vol. xxx, p. 570. (Described 



as below as a new species.) 

 Eoorlhis kichouensis (WALCOTT), 1912, Monogr. U. S. Geol. Survey, vol. LI, p. 782, plate LXXXIX, 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 

 stria; if on the shell originally, they have been removed by the wearing off of the 

 outer surface. 



