268 



NORTH-CAROLINA GEOLOGICAL SURVEY. 



FAMILY PYRAMIDELLIDAE. 



This family, when restricted to existing species, embraces 

 shells of a small size, and which are spiral slender, pointed 

 and turrited ; aperture small, and the columella has one or 

 more prominent plaits. Shells which, in form, bear a very 

 close resemblance to this family, are found in very ancient 

 rocks, but which, in comparison with those of the present day, 

 were of a gigantic size. 



PYRAMIDELLA ARENOSA. CON. (Fig. 154.) 



Shell smooth, and still somewhat polished, subulate ; suture 

 angularly channelled, columella with two folds ; outer lip pro- 

 vided with three teeth. It is a rare shell in the miocene of 

 North-Carolina. 



FIG. 154. FIG. 161. FIG. 158. FIG. 160. FIG. 157. 



PYRAMIDELLA RETICULTA. N. S. (Fig. 155.) 



Shell turrited; whirls, six or seven, and ornamented by 

 numerous longitudinal ribs, and less distinct spiral lines giv- 

 ing the surface a reticulated appearance ; columella three 

 plaited. It closely resembles the P. elaborata H. E. Lea. 



FIG. 155. FIG. 156. FIG. 159. FIG. 162. 



FIG. 164. 



CHEMNITZIA. (Fig. 156.) 



Shell slender, elongated ; many whirled ; whirls longitudin- 

 ally plaited and marked by obscure spiral lines ; aperture 

 simple, ovate. Bather rare in the shell marl at Magnolia. 



