TO GEOLOGY. 61 
GENUS ASTARTE. Sowerby. (Crassina of Lamarck.) 
A. recurva. Plate 2. Fig. 34. 
Description. Shell subrotund, angular before, emargin- 
ate behind, deeply emarginate before the beaks, rather 
compressed, concentrically and largely striate, deeply fold- 
ed behind; substance of the shell rather thick; beaks 
very much elevated and recurved ; lunule large, deeply 
impressed, cordate ; escutcheon long—lanceolate ; pos- 
terior slope bicarinate ; teeth obliquely curved ; cicatrices 
impressed ; margin finely crenulate. 
Diam. .2, Length .4, Breadth .4, of an inch. 
Observations. I have seen no species of this genus with 
so elevated and recurved a beak as this. It is remarkable 
for its curved teeth, the very deep impression of the lunule, 
which, together with the recurviture of the beak, causes 
the point of the latter to be quite hooked. The deep fold 
or furrow, behind, forms on its edges sharp ridges, which 
are imbricate. In one specimen, I observed longitudinal 
strie diverging from the beaks and nearly reaching the 
margin. 
A. Nicklinii. Plate 2. Fig. 35. 
Description. Shell transversely elliptical, subangular be- 
hind, emarginate at posterior basal margin, concentrically 
and largely ribbed; beaks compressed, pointed; lunule 
