HAMILTON GROUP. 
201 
This is a very glabrous shell, with a prominent line of growth near the beaks, and one or 
two more near the margin, leaving the greater part of its area entirely plain. 
Localities —Moscow, Eighteen-mile creek. 
4. Strophomena inequistriata (Conrad, Jour. Acad. Nat. Sci. Vol. 8, p. 254, pi. 14, 
fig. 2). — Somewhat semicircular ; lower valve very convex; surface covered with radiating 
striae, every fourth or fifth of which is more prominent than the rest; striae increasing in 
number towards the margin ; hinge extremities angulated. 
There seems to me very good reason for considering this form and the S. mucronata (Con¬ 
rad, Jour. Acad. Nat. Sci. Vol. 8, pi. 14, fig. 10), as identical, and that both are identical 
with Orthis interstrialis (Phil. Palceozoic Fossils, p. 61, pi. 25, fig. 103, a, b, c, d). 
In the calcareous shales of the Hamilton group, its form is often better defined and more 
rotund, though the striae are less sharp ; while in the Chemung rocks, it is usually compressed, 
and very frequently the shell is partially or entirely removed. 
Locality —Seneca lake ; Moscow. 
5. Delthyris zigzag, n. s.— Upper valve semicircular, moderately convex ; surface marked 
by 16 to twenty rounded ribs, which are crossed by very prominent undulating or zigzag la¬ 
minae ; mesial fold of the upper valve somewhat duplicate, of the lower valve deeply impressed 
and elevated in front. 
So far as known, this fossil is confined to the Moscow shale. It is readily distinguished by 
the prominent zigzag laminae. 
6. Calymene bufo (Green, Monograph, p. 41). — Head semicircular; middle lobe very 
large, obtuse in front; surface covered with numerous depressed pimples ; articulations of the 
body 10, of the tail 8 ; articulations of the middle lobe apparently double, those of the lateral 
lobe deeply grooved near their junction with the central lobe. 
The fossil from which the drawing is taken is partially coiled, so that the tail is not visible. 
It is one of the most abundant fossils of the group, occurring either perfect or in fragments at 
nearly every locality. 
Localities —Moscow'; Seneca lake, and Eighteen-mile creek. 
7. Cryphceus calliteles. Green. — Head lunate, with the posterior angles of the buckler 
extended to the fifth rib of the body. Articulations of the abdomen 10; of the tail, 10 in the 
middle, and 6 in the lateral lobes. Articulations of the lateral lobes free at the margin, and 
forming a beautiful punctulated fringe. Structure of the head and eyes like the Asaphus. 
Surface pimpled, and, apparently from the removal of these, punctulated. 
Localities —Moscow ; Pavilion ; Eighteen-mile creek. 
8. Loxonema nexilis (Phil. Palaeozoic Fossils, p. 99, pi. 38, fig. 183. Terebra nexilis, 
Sowerby, Geol. Trans. 2d Series, Vol.v, pi. 54, fig. 17.) — Elongated, subulate; volutions 
convex, with alternating longitudinal arched furrows and raised lines, retiring from and ad¬ 
vancing toward the sutural lines. (The specimen figured is imperfect.) 
[Geol. 4th Dist.] 26 
