102 RESEARCH IN CHINA. 
and flat border on the pygidium. It is of the type of and very closely related to 
A. parvifrons Linnarsson [1869; see Tullberg, 1880, plate 2, figs. 27, 28], from which 
it differs in the proportion of the glabella to the length of the cephalic shield and 
in the flatter margins of the cephalic and caudal shields. 
Formation and Locality—Middle Cambrian: (C57) In limestone nodules in 
the lower shale member of the Kiu-lung group [Blackwelder, 1907a, pp. 37 and 40 
(first list of fossils)], 3 miles (4.8 km.) south of Kao-kia-p’u, and 4 miles (6.4 km.) 
north of Sin-t’ai-hién, Sin-t’ai district, Shan-tung, China. 
Agnostus parvifrons latelimbatus Lorenz. 
Plate 7, Figures 1, 1a. 
Agnostus parvifrons latelimbatus LORENZ, 1906, Zeitschr. deutsch. geol. Gesellsch., vol. Lvim, pt. 01, 
p. 84, plate 4, figs. 9, 9a—b; plate 5, figs. 10, 11. (Described and illustrated as a new variety.) 
The original specimens of this variety of Agnostus parvifrons Linnarsson are 
unsatisfactory. The species is represented, but the characters for determining the 
variety are not clear, owing to the imperfect specimens. 
Formation and Locality—Middle Cambrian: Kiu-lung group, Wang-tschuang, 
Shan-tung, China. 
Agnostus sp. undt. 
One specimen of a pygidium of an Agnostus of the same general character as 
that of A. douvilléi Bergeron [p. 1c0] occurs in limestones of the lower Ch’au-mi-tién 
formation. In the absence of the cephalon I will only call attention to the occur- 
rence. 
Formation and Locality—Upper Cambrian: (C84) Purplish-gray limestone 
about 100 feet (30 m.) above the base of the Ch’au-mi-tién formation [Blackwelder, 
19074, p. 36 (part of first list of fossils)], in road at northeastern corner of small 
village near Ch’au-mi-tién, Shan-tung, China. 
Collected by Eliot Blackwelder. 
A species of Agnostus is indicated in the upper beds of the Ch’ang-hia formation 
by the presence of a single pygidium that differs from A. chinensis Dames [p. 99] 
in having a proportionately stronger and more rounded marginal rim. ‘The median 
lobe is not so broad in its posterior half and not so convex. 
Formation and Locality.—Middle Cambrian: (C 24) Near top of black oolite group 
in the uppermost layers of the Ch’ang-hia formation [Blackwelder, 1907a, p. 33 
(part of last list of fossils)], 2 miles (3.2 km.) east of Ch’ang-hia, Shan-tung, China. 
Collected by Eliot Blackwelder. 
Genus MICRODISCUS Emmons. 
Microdiscus Emmons, WALCOTT, 1886, Bull. U. S. Geol. Survey, No. 30, p. 152. 
Microdiscus orientalis Walcott. 
Plate 7, Figure ro. 
Microdiscus orientalis WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xx1x, p. 24. (Described and dis- 
cussed as a new species essentially as below.) 
There is in the collection but a single specimen of the matrix of a portion of 
the cephalon of this species. This indicates the cephalon to have been semicircular 
in outline, with a strong, rounded, frontal border, marked by ten or more transverse 
furrows, very much in the same manner as M. connexus Walcott [1887, p. 194, plate1, 
figs. 4, 4b]. In front of the border there is a very narrow, slightly elevated rim. 
