NORTH-CAROLINA GEOLOGICAL SURVEY. 



275 



shaped or sub-conical, and passing into a cone, within which 

 there is an appendage somewhat similar in form to the outer 

 cone. These cones are frequently sub-spiral. They adhere 

 to rocks and stones with their apertures below. 



CRUCIBULTJM COSTATUM. 



Shell rather thick, circular at base, and furnished with 

 strong but rather irregular ribs ; apex sub-central ; margin 

 crenulated. 



CRUCIBULTJM RAMOSUN. CON. (Fig. 191.) 



Shell ovate ; apex sub-central ; ribs prominent and orna 

 mented by a series of subordinate diverging ridges, but par 

 tially interrupted by the lines of growth ; inner cup sub-con 

 ical, entire, and marked by circular ridges, or lines of growth. 



FIG. 196. 



FIG. 192. 



FIG. 193. 



FIG 195. 



FIG. 191. 



FIG. 194. 



