62 RESEARCH IN CHINA. 



A careful comparison of the type specimens of this species with the series of 

 specimens from Manchuria shows them to be so similar in form and surface sculpture 

 that I do not hesitate to identify the latter as Micromitra sculptilis (Meek). The 

 species has a wide distribution in the Rocky Mountain Province of America, and it 

 ranges from the Upper Cambrian down into the Middle Cambrian [Walcott, 19126, 



PP- 341-342]. 



Formation and Locality. 1 Middle Cambrian: (35 n and 35 r) Fu-ch6u series; 

 limestones near the base just above the white quartzite [see Blackwelder, 19076, 

 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, Man- 

 churia, China. 



Collected by J. P. Iddings and Li San. 



PATERINA Beecher, Subgenus of MICROMITRA. 



For discussion of the subgenus see Monogr. U. S. Geol. Survey, vol. LI, 

 1912, p. 343. 



Micromitra (Paterina) labradorica orientalis (Walcott). 



Plate i, Figure 8. 



Iphidella labradorica orientalis WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxvm, pp. 305-306. (Char- 

 acterized as below as a new variety.) 



Micromitra (Palermo) labradorica orientalis (WALCOTT), 1912, Monogr. U.S. Geol. Survey, vol. Li, p. 348, 

 plate n, fig. 1 1 . (Copy of the preceding reference.) 



Only one dorsal valve of this shell occurs in the collection. Its general form 

 and surface characters are very much like those of Micromitra (Paterina) labradorica 

 swantonensis (Walcott) [19126, pp. 348-349, plate n, figs. 3, 3a-/]. The varietal 

 name is given more on account of the fact that this shell occurs in China and the 

 variety swantonensis on the eastern side of the North American continent than 

 from any marked differences between the shells from the two localities. It may be 

 that with a good series of shells from China differences would be found that are not to 

 be determined with only the single shell for comparison. 



Formation and Locality. Middle Cambrian : (C 5) Lower limestone member of 

 the Kiu-lung group [Blackwelder, 190717, pp. 37 and 39 (first list of fossils), and fig. 

 8a (bed 30), p. 29], 3.2 miles (5.1 km.) southwest of Yen-chuang; and (CO), lower 

 limestone member of the Kiu-lung group [idem (third list of fossils), andfig.8a(bed 33), 

 p. 29], 3 miles (4.8 km.) southwest of Yen-chuang, Sin-t'ai district, Shan-tung, China. 



Micromitra (Paterina) lucina Walcott. 

 Plate i, Figures 7, 70. 



Micromitra (Paterina) lucina WALCOTT, 1911, Smithsonian Misc. Coll., vol. 57, No. 4, pp. 73-74, plate 

 14, fig. i. (Described and discussed as a new species, essentially as below.) 



Ventral valve depressed subconical, with a minute beak curving over and con- 

 cealing the pseudodeltidium. The cardinal slope is bent abruptly backward and 

 downward so as to form a narrow false area on each side of a wide, open, triangular 

 space. Dorsal valve transverse, gently convex, with the nearly straight posterior 

 margin shorter than the greatest width of the valve ; beak minute, marginal ; false 

 area unknown. 



Surface marked by concentric, slightly irregular, rounded lines and ridges of 

 growth that may or may not be grouped in bands of varying width. A dorsal valve 

 shows a few fine, faint, radiating ridges. 



'Only the Chinese localities are here given; for the other occurrences of M. sculplilis, see Walcott, 19126, 

 PP- 34>-342- 



