OE DENISON UNIVERSITY. 
43 
tabular arrangement based ^on the original descriptions will afford the 
basis for comparison. The following order being preserved: 
I. S. striatiformis, 2. S. centronata, 3. S. marionensis, 4. S. 
biplicatus. 
Species. 
Hinge. 
Lateral extremities. 
Ventral beak. 
Ventral area. 
d 
a 
r 
0 
■ 
Ventral sinus. 
Dorsal fold. 
Pointed, 
Mod’rate, 
1 
Shorter. 
Rectangular 
curved. 
arched. 
Wide 
Narrow, deep 
Narrow, low. 
3 
longer. 
acute. 
4 
“ 
“ ! 
Narrow . 
Wide 
“ 
X 
E 
c 
s 
‘x 
lU X 
C cc 
8 
c 
c 
0 
Q C (P 
P 
0 <v 
0 ? 
J 
S 
5 is > 
is 
'B 
3 
Numerous, small, 
round, bif rc’ting 
fi 
cc 
w 
1 
8 
8 
.5(1 
Minute striae 
2 
— 
3—5 
36—4(1 
3 
— 
3—4 
50 
4 
(j 
30 
Between S. marionensis and S. centronata it is very hard to dis- 
cover any point of dissimilarity. In fact we cannot distinguish speci- 
mens from the Cuyahoga shale, the locality of S. centronata, from 
specimens of S. marionensis from near the middle of the lower divis- 
ion of the Waverly in Licking Co. S. striatiformis is restricted to the 
upper portion. 
Spirifer marionensis, Shumard. 
(Plite VI, Figs. 3-4 ; Plate VII, Fig. 1 1 ; Plate IX. Fig. i ?) 
Cf. S. ce 7 itronata. Win. 
Our figures give a good idea of the range of variation exhibited, 
though in the smaller shells the mucronate extension of the hinge is 
more marked. On the largest shells there are rarely more than four 
plicae on the fold or sinus and the lateral margins are usually quite 
oblique. This species has been found in the shale near the east end 
of the bridge crossing Moot’s run, four miles west of Granville, and 
the layer of nodules one mile west. The horizon being supposed to 
