tfORTH-CAROLINA GEOLOGICAL STJEVEY. 



313 



Fio. 256. 



purpose they attach themselves to a grain of sand, which will 

 generally be still fqund at the point of growth ; some of the 

 miocene ones are nearly half an inch in diameter. 



POLYPAIRA. ASTRAEA BELLA. (Fig. 256.) 



The stars are polygonal, variable, rather deep, lamellar 

 lamellae twelve, with alternating ones, denti- 

 culated, contiguous, or separated by their par- 

 titions. 



Common in the miocene incrusting shells, 

 and various bodies found in a marl bed. 



ASTKAEA. (Fig. 256a.) 



Irregularly branched ; stars deep and rather distant, though 

 in some places contiguous as in the Bella; intermediate spaces 

 without pores, but bordered by lines to which the lamellae 

 extends ; lamellae denticulated, as in A. Bella, and provided 

 also with the same number, and similarly arranged. Miocene. 



Fro. 256a. 



