872 Barrett—Coralline Limestone from Montague, New Jersey. 
The Strophodonta* (Leptena) of Pl. 74, figs. 3a and 3b, 
Pal. N. Y., vol. ii, is very abundant in the lower beds of this 
Coralline or Niagara limestone. Its ventral valve has the 
surface characters represented enlarged in fig. 30,+ its dorsal 
valve has the flat radiate strise and the concentric, crowded, 
thread-like strize represented in fig. 6d of the same plate. Both 
valves have a denticulated hinge line, the cast of the interior of 
the ventral valve resembles fig. 4a, the cast of the interior of 
the dorsal valve is near figs. 6a and 6 of the same plate. The 
impression of the cast of the interior of the dorsal valve shows 
widely divergent socket-ridges,t with three subparallel ridges in 
the bottom of the shell, the mesial longest and extending two- 
thirds the length of the valve toward the front. Old shells 
have about the size and form of fig. 4a. Shell flat, undulated, 
inequale and the Strophodonta (Ne 
the other species being represented by a very few depauperate 
N. Y. Pal for the Niagara group. The mural pores show 
plainly in thin vertical sections, or, better yet, in sections cut 
obliquely transverse to the axis of growth. 
* T have labelled it provisionally S. Nearpassii 
os 
. 
more arenate 
t Cardinal processes not apparent. 
= eek hapa ga ieccolendatamucliate nee > 2 eh a IRA 
SE Saar 24 c= 
