CARHONIFKROUS. 



IOI 



in the same sense as the I tolites are organic, con- 

 ng of rounded grains cemented together which 

 to have originated in the growth of marine 

 e allied to existing Nullipoi 



/ J Limestone. 



The Carboniferous Limestone being in part a 

 alline limestone, includes a large number of 



ils. Probably the commonest genera found in 

 Europe are Ample* \thophyllum % Lithostrotion^ 



and Zaphrentis. They 



numerous in spe 



and abundant in individ- 



[] of ex- 

 tinct ty] 



Echinodermata 

 jely represented ; 

 and propably in n< 



I is there a 



number of crinoids. The 

 principal genera are A< 

 tinocrinus, ( lyathocrinus 

 and Platycrinus. 



The shells, however, 



are even more distinctive. The tWO genera P ro- 



md Spirt/era comprise more than half the 



species of Brachiopods. Rhynchotulla is well repre- 



ted in association with Terebratula* The latter 



two survive all subsequent revolutions of the earth. 



Among the other shells, the bivalves Pinna^ 



Lima and Anomia, Avicula^ Pecten are associated 



with Modiola, Mytilus, Area, Solenopsis^ Solemya, 



types which appear to survive to the present day, 

 more common on British coasts than in the car- 

 boniferous rocks. 



Fio. 14.— Productus, a brachio- 



pod Of th' eft *U lime- 



stone. 



