OE DENISON UNIVERSITY. 
73 
inch conglomerate above the quarry rock in the south Newark quarry. 
It is here associated with A. venfricosa, Edmondia sp. Sanguinohtes 
obliquus, and Frothy rus meeki. 
The following measurements illustrate the range of variation at 
this place : 
j Length. 
Height. 
1 Thickness. 
Height at 
from post, end 
Thickness at 
14 from pos- 
terior. 
Angle of an- 
tero- ventral 
margin. 
[ Angle of an- 
tero-dorsal. 
1 Anterior wing 
Length to 
height to 
thickness. 
I 
51 
23 
22 
23 
18 
42° 
120° 
5 
I-- 45--43 
2 
48 
23 
21 
2^ 
17 
40° 
113P 
4 
I -- 47 --43 
3 
47 
24 
22 
25 
20 
40° 
112° 
3 
1-.51-.46 
4 
53 
23 
20 
22 
H 
38° 
121° 
4 
•-• 43--37 
.S 
(52) 
23 
20 
22 
16 
37 ° 
1 ^ 3 ° 
4 
6 
24 
22 
22 
18 
7 
(26) 
1 2 
10 
7 
7 
8 
M 
1 1 
•3 
1 7.5 
9 
47 
23 
22 
24 
17 
10 
35 
L 
17 
19 
1 15 
Allorisma winchelli has once been found in shales above congl. I, 
showing that it was continuous throughout ihe period during which 
the free-stone was deposited. The animal lived buried in the mud^ 
and is found wdth the valves in connection oblique to the lamination, 
anS only in rocks which were originally mud of the shallow bays. 
Alloidsina ventricosa, Meek. 
(Plates VUI, Fig. 6; Cf. Plate VII, Fig. 33.) 
Our specimens differ considerably from Meek’s description and 
also among themselves. The one figured expresses the extreme de- 
velopment of the tendency of the species, being shorter and more 
abruptly curved antero-ventrally and with more prominent beaks than 
others. A well marked ridge marking off the antero-umbonal slope 
is especially characteristic. 
Length 34 (24); height 29 (19); thickness 18 (13); height at ^ 
from posterior 22 (15); thichness at same point 13 (10); anterior wing 
5; angle of postero-ventral margin with hinge line about 56°. Meas- 
urements in parenthesis are of another specimen. 
