FOSSILS FROM NORTHWESTERN AMERICA. iO. 
curved. Valves very thin. This shell is remarkable for having the peculiar lustre and 
consistence of many species of Anomia. The shell is partially removed, and the surface 
exhibits obsolete radiating lines.—Plate 19, fig. 1, 1 a. 
? Plate 19, fig. 2. A broken shell from the argillaceous shale below 
Astoria. 
Dotrum peTrRosum (Conrad).—Ovate globose with revolving ribs about on the body 
whorl ; shoulder angulate, tuberculate, below the angle having a slightly concave space, 
with a revolving prominent line. Spire scalariform, and rather elevated ; volutions 5. 
—Plate 19, fig. 3 a, b, 4 a, b, 5 a, 6, natural size. 
Astoria, Oregon. 
There are three specimens of this species, all of which are casts. In the smallest the 
tubercles are very prominent, and less so in the others; and there is a row of small 
tubercles below the flattened space on the upper part of the body whorl. 
SreareEtus scoputosus (Conrad).—Obliquely oval, somewhat ventricose, flattened on 
the upper half of the body whorl. Disks with numerous revolving lines,—Plate 19, 
figures 6, 6 a, b, c, d, natural size. 
Astoria, Oregon. 
Narica saxga (Conrad).—Subglobose. Whorls five, convex, with distinct lines of 
growth; a broad brown band at base of the shell, and a lighter-coloured brown band re- 
volves on the upper part of the whorls, contiguous to the suture; a narrow darker band 
margins the suture. Umbilicus large, partially covered by a callus.—Plate 19, fig. 7 
a,b. Natural size. 
Astoria, Oregon. 
This species closely resembles IV. heros (Say) in contour and in the umbilicus; but 
the brown band at the base is, I believe, wanting in the heros. 
Buta perrosa (Conrad).—Cylindrical, narrow, sides gently curved.—Plate 19, figure 
8, natural size. 
Astoria, Oregon. 
CREPIDULA PR#RUPTA (Conrad).—Oblique, oblong, somewhat elliptical and ventri- 
cose, with simple lines of growth. Sides flattened. Beak narrowed and laterally 
curved ; the side towards which the apex is directed, slightly contracted, and having a 
somewhat sinuous margin.—Plate 19, figs. 9, 9 a, natural size; 10 a, b, views of a cast, 
probably of this species, 
Astoria, Oregon, 
CREPIDULA 
1 This species, of which there is only a cast in the collections, is 
very much depressed, with the summit narrow and nearly straight, subacuminate, 
broadest across the beak, the sides there being somewhat dilated.—Plate 19, figs. 11 a, b, 
natural size. 
Astoria, Oregon. 
RosTELLARIA INDURATA (Conrad).—Subfusiform, with oblique, curved, rounded ribs, 
