PLATE LXXXII. 
cl. Cardinal sear. F’. Cast of foraminal tube. 
F. Foramen. vs. Vascular sinuses. 
YORKIA WANNERI Walcott (p. 612). 
Fieure 1. ee gue corrugated ventral valve, drawn from a cast of a natural matrix. U.S. Nat. Mus. Cat. No. 
26433]. 
la. Exterior a side outline of a smooth ventral valve, drawn from a cast of a natural matrix. U.S. Nat. 
Mus. Cat. No. 26433a. Specimen figured by Walcott [1897b, Pl. LX, fig. 1]. 
lb. Top view, back view, and side outline of an elevated ventral valve, drawn from a cast of a natural matrix. 
U.S. Nat. Mus. Cat. No. 26433b. 
le. Top and back views of cast of the interior. U.S. Nat. Mus. Cat. No. 26433c. Specimen figured by Walcott 
[1897b, Pl. LX, fig. la]. 
1d. Exterior of a dorsal valve, drawn from a cast of a natural matrix. U.S. Nat. Mus. Cat. No. 26433d. 
le. Cast of the interior of the posterior portion of a ventral valve. U.S. Nat. Mus. Cat. No. 26433e. 
lf and lg, Casts of the interiors of ventral valves, with side outlines of same. U.S. Nat. Mus. Cat. Nos. 26433f 
and 26433g, respectively. The specimen represented by figure lg, the type, was figured by Walcott 
[1897b, Pl. LX, figs. 1b and Ic]. 
th. Cast of the interior of a dorsal valve. U.S. Nat. Mus. Cat. No. 26483h. Specimen figured by Walcott 
[1897b, Pl. LX, fig. 1d]. 
li. Area of dorsal valve drawn from the cast of a natural mold (original specimen missing). U.S. Nat. Mus. 
Cat. No. 264331. Specimen figured by Walcott [1897b, Pl. LX, fig. le]. 
The specimens represented are all from Locality 49, Lower Cambrian sandstone on Codorus Creek, near Emigsville, 
York County, Pennsylvania. 
YoRKIA? WASHINGTONENSIS Walcott (p. 613). 
Ficure 2. Cast of the interior of a ventral valve from Locality 37b, Lower Cambrian limestone 0.25 mile (0.4 km.) east 
of Salem, Washington County, New York. U.S. Nat. Mus. Cat. No. 26484a. Type specimen 
figured by Walcott [1897b, Pl. LX, fig. 3]. 
2a. Cast of the interior of a dorsal valve from Locality 338n, Lower Cambrian, western belt of conglomeratic 
limestone, Rensselaer County, New York. U.S. Nat. Mus. Cat. No. 52207a. 
YoRKIA? ortENTALIS Walcott (p. 612). 
Figures 3 and 3’. Top and side views of ventral valve from Locality €71, Middle Cambrian limestone in Kichou 
formation [Willis and Blackwelder, 1907, pp. 139 and 145], 4 miles (6.4 km.) southwest of Tungyu, 
Shansi, China. U.S. Nat. Mus. Cat. No. 52521a. This is the type specimen. 
3a. Enlargement of the outer surface of the specimen represented by figure 3. 
YorxKIA? MiQquELI Walcott (p. 611). 
Fieure 4. Exterior of ventral valve from Locality 342a, Lower Ordovician?, barren quartzitic beds at Coulouma, 
Department of Hérault, France. This is the type specimen. Collection of J. Miquel. 
DiscINoPsis GULIELMI (Matthew) (p. 720). 
Figure 5. A compressed ventral valve. Type specimen, figured by Matthew [1886, Pl. V, figs. 14c and 14d]. 
5a and 5b. Interiors of ventral valves. Figure 5a is drawn from the specimen figured by Hall and Clarke 
[1892a, Pl. III, fig. 21, and 1892c, Pl. III, figs. 21 and 22]. Figures 5a and 5b are drawn from speci- 
mens among those figured by Matthew [1886, Pl. V, figs. 14, 14a-b, and 14e], but closer identification 
is impossible. 
5e. Interior of a dorsal valve. Specimen figured by Hall and Clarke [1892c, Pl. III, fig. 23]. Its identifica- 
tion with any of the figures given by Matthew [1886, Pl. V, figs. 14, 14a—b, and 14e] is impossible. 
The specimens represented are all from Locality 301g, Middle Cambrian sandstones of Division le of Matthew at 
Portland, now a part of the city of St. John, St. John County, New Brunswick. They are in the collection of the 
University of Toronto, Canada. 
274 
