a 
: 
PLATE LXXXII. 275 
Disctnopsis? sutcatus Walcott (p. 721). 
Figure 6. Cast of the interior of a ventral? valve, the type specimen, from Locality €56, Upper Cambrian Chaumitien 
limestone at Pagoda Hill, 1 mile (1.6 km.) west of Tsinan, Shantung, China. U.S. Nat. Mus. Cat. 
No. 52522a. 
DEARBORNIA CLARKI Walcott (p. 614). 
Ficures 7 and 7a. Exteriors of ventral valves. U.S. Nat. Mus. Cat. Nos. 52214a and 52214b, respectively. Figure 
7, that of the type specimen, is copied from Walcott [1908d, Pl. VIII, fig. 7]. 
7b. Cast of the interior of a ventral valve. U.S. Nat. Mus. Cat. No. 52214c. 
7c. Cast of the interior of a dorsal valve. U.S. Nat. Mus. Cat. No. 52214d. 
7d. Exterior of a dorsal valve. U.S. Nat. Mus. Cat. No. 52214e. 
The specimens represented are all from Locality 9k, Middle Cambrian limestone forming 1c of the Dearborn River 
section [Walcott, 1908f, p. 201], eastern part of the Lewis and Clark National Forest, Montana. 
TREMATOBOLUS EXCELSIS Walcott (p. 617). 
Ficure 8. Top view, with outline of side and back views, of a cast of a ventral valve, the type specimen. U.S. Nat. 
Mus. Cat. No. 52208a. Copied from Walcott [1908d, Pl. VIII, fig. 8]. 
8a and 8b. Top view, with outline of side and back views, of exteriors of ventral valves. U.S. Nat. Mus, 
Cat. Nos. 52208b and 52208c, respectively. 
The specimens represented are all from Locality 53, Lower Cambrian sandstones in the lower portion of 3d of the 
Waucoba Springs section [Walcott, 1908f, pp. 187 and 188], 1 mile (1.6 km.) east of Saline Valley road about 2.5 miles 
(4 km.) east-northeast of Waucoba Springs, Inyo County, California. 
