oo 
PLATE LXXXyV. 285 
BILLINGSELLA COLORADOENSIS (Shumard)—Continued. 
Figure lu. Interior of dorsal valve from impression taken from natural cast, with outline of posterior view. Probably 
from Locality 97, Upper Cambrian ‘‘St. Croix sandstone,’’ Reads Landing, Wabasha County, Minne- 
sota. U.S. Nat. Mus. Cat. No. 34771g. Drawn from an artificial cast, the original mold of which can 
not be located. The cast was in a tray with specimens from Locality 97, but it may not belong 
there. (See note under figure In.) 
ly. Interior of dorsal valve associated with the specimen represented by figure lc. U.S. Nat. Mus. Cat. No. 
34774c. 
lw. Interior of dorsal valve associated with the specimen represented by figure la. U.S. Nat. Mus. Cat. No. 
35213f. Copied with slight alterations from the figure given by Walcott [1899, Pl. LXI, fig. 1b]. 
1x. Cast of the interior of dorsal valve, with side and posterior outlines. U.S. Nat. Mus. Cat. No. 51403b. 
From Locality 5a. (See fig. 1b.) 
ly. Cast of dorsal valve associated with the specimen represented by figure 1d. U.S. Nat. Mus. Cat. No. 
34771d. 
1z. Cast of posterior portion of interior of dorsal valve from Locality 5b, Middle Cambrian Langston limestone, 
2 miles (3.2 km.) southeast of Malade, Oneida County, Idaho. U.S. Nat. Mus. Cat. No. 34776a. 
