Wincliell.] 
252 
[ Jtill. 4 ? 
width of the valve, slightly produced anteriorly. Dental lamellae extend¬ 
ing three-fifths the length of the valve, not approximated at the rostral 
extremity. Muscular scars striate. Surface of cast destitute of plica¬ 
tions, hut deeply marked toward the front by wrinkles of growth. 
Transverse diameter, one and five-eighths inches ; antero-posterior di¬ 
ameter, one inch ; height of area, three-eighths of an inch. 
This species is more completely destitute of plications than any other 
in rocks of the same age ; and this character, together with the length, 
width and flatness of the area, renders it necessary to admit it as new. 
Spirifera Carteri, Hall (/S'. Vernonensis , Swallow). Very abundant 
in bed No. 4, Sciotoville, Ohio ; rare in bed No. 5, Rockville. A single 
specimen labelled Granville, is, probably (judging from the matrix), from 
Sciotoville. Occurs also, near Shafer’s, Penn. 
Spirifera Marioeeesis, Slium. (Mo. Geol. Rep., Pt. ii, p. 208, pi. C., 
fig. 8, a-d.) Several specimens from bed No. 4, Sciotoville, Ohio. These 
specimens agree tolerably well with the description of this species, and 
with specimens from Clarksville, Mo. This seems to be a species, how¬ 
ever, which exhibits a tendency to graduate on the one hand, into 8. bi¬ 
plicata, and on the other, into 8. Carteri. Young specimens exhibit a 
well defined ventral sinus, with about two incipient plications; and having, 
at this age, sharper dorso-lateral angles, they closely approximate 8. bipli- 
cata. Large specimens, on the contrary, can scarcely be distinguished 
from 8. Carteri, save by the less pronounced sinus and fold. 
There are, indeed, six species described from rocks of this age, which 
need to be re-examined and compared, viz : 8. Marionensis , Slium., 1855; 
8. Carteri, Hall, 1857-8 ; 8. biplicata, Hall, 1858 ; 8. Vernonensis, Swal¬ 
low, I860 ; 8. Osagensis, Swal., I860 ; and 8 . Missouriensis, Swal., 1860. 
The three first are, perhaps, distinct species—possibly all the others. 
Spirifera subrotuedata, Hall (Iowa Geol. Rep., p. 521). From 
bed No. 4, Sciotoville, Ohio. 
On some of the casts no striations are certainly seen, except over a lim¬ 
ited space one side of the beak. 
Spirifera biplicata ? Hall. A single imperfect specimen, from No. 
4, Sciotoville, Ohio. See remarks above on 8. Marionensis. 
Spiriferiea solidirostris, White (Bos. Jour. VII, 232). Collected 
by Rev. H. Herzer, at Newark, Ohio, and by Prof. Andrews, from bed 
No. 4, Sciotoville, and bed No. 5, Rockville. 
/ Syriegothyris typa, Win. (Proc. Acad. N. S., Phil.) This species 
occurs quite abundantly in Ohio. Mr. Herzer and Prof. Andrews have 
furnished over a dozen specimens from Newark. In bed No. 4, Scioto¬ 
ville, it forms, with Spirifera Carteri and several other species, the prin¬ 
cipal mass of a highly ferruginous stratum of sandstone. It occurs 
freely, also, near Shafer’s^ in Pennsylvania. 
From Newark specimens may be worked out good views of both valves, 
and of the bifariously striated area. Traces of the pseudo-deltidiura may 
also be seen, and it appears that the dental lamellae are very deep, but the 
essential structure of the genus dqes not appear. There is one ex( 
7- J 
oui a 
