MADE BY DR. ANTONIO RAIMONDI IN PERU. 28t 



CRASSATELLA, Lam. 



C. CAUDATA, n. s., PI. 40, fig. 18. 



Shell elongate cuneiform, beaks very anterior with the posterior cardinal mar- 

 gin sloping nearly straight to the posterior end, which is narrow and obliquely 

 truncate ; anterior end sloping nearly straight from the beaks to near the base, 

 where it is most prominent and rounded. A rounded angle runs from the beaks 

 to the posterior basal angle, behind which the surface is flat or very slightly con- 

 cave. Surface marked only by coarse lines of growth. Lunule deep and cordate, 

 its margin rounded. The young shells are proportionally much shorter and broader 

 and not so acute posteriorly as the adults. 



Figures. Natural size. 



Localities. From the black shales of the coal mine of Pariatambo and from the 

 limestones of the Cerro del Ventanillo. 



Remarks. A common species, easily recognizable by its elongate, wedge-shaped 

 form. It is perhaps the most abundant fossil in the black shales of the coal mine, 

 associated with Amynonites carbonarius. I have never seen the hinge, but have not 

 hesitated in referring it to the above genus, on account of its marked external 

 characters. 

 C, sp. indet. 



A very ventricose cast, apparently of this genus, comes from the Cretaceous 

 locality of the hacienda of Macanga. It retains none of the shell, but from its 

 shape and from the impression of the hinge teeth, it seems to be a Crassatella. 



CARDITA, Brug., Lam. 



C. EXOTICA, d'Orb. sp., PI. 41, f. 1, 2. 

 Astarte id., d'Orb., Am. Mer., p. 83, PI. 18, f. 11-12. 

 id., d'Orb., Foss. Col., p. 48, PL 3, f. 11-12. 



Shell obliquely elongate subquadrate; beaks about a fourth of the distance 

 from the anterior end; directly under the beaks the anterior end is concave; most 

 prominent a little above the middle, below which point it curves regularly into 

 the base ; posterior cardinal margin sloping convexly ; posterior end broad and 

 obliquely truncate ; surface marked by about twenty-four square ribs, roughened 

 by the crossing of irregular ridges of growth ; of these ribs, six or seven, smaller 

 than the others, are on the posterior face of the shell; between the large ribs are 

 broad, concave interspaces ; lunule small, deep, cordate ; inner margin crenulate. 



Figures. Natural size. 



Localities. Hill near the Hacienda del Imperial near Cailete, and near the town 



