: rv ierease in the length of the compressed co 
>. Chemistry and Physics. 265 
2. A. triplistriata, n.s. Shell small, inequilateral, hinge-line 
straight, and sloping posteriorly. Anterior’auricle the argest, 
bordered by an elevated ridge, umbones moderate, beaks hidden. 
Anterior portion of the surface ornamented with 80 crenulated 
® for the most part arranged in triple series. The posterior 
Portion has 12 crenulated striz, which are stronger than those 
of the anterior portion. 
mensions: height 0:5 of an inch; width, ditto. ‘ 
Position and locality: in calcareous shales at Summit Station, 
Columbiana Co., Ohio. 
Posipoxomya (Bronn).—P. striata, n.s. Shell small, subdis- 
coidal, Hinge-line straight, nearly equal to the width of the 
GERVILLA (Defrance).—G. Auricula, n.s. Shell elongated, 
_ inflated, almost cylindrical, apex appressed to the hinge-line, near 
the anterior extremity which is rounded and earless. Posterior 
-xitemity prolonged, curved, acute; posterior ear winged, reach- 
ing one half the width of the shell; dingo line straight. Surface 
smooth, save at the anterior extremity, where a few incremen 
lines are visible, 
pemensions : length, 0°75 of an inch; height 0:20; length of 
nge-line with ear, 0-45 of an inch. . 
sition and locality: in the roof of Danville coal, Danville, Til. 
orth Egremont, Mass., Dec. 10, 1857. . 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PHYSICS. 
2 into a trough full of water, so that the interfering rays traversed 
th of th 
