Zoantharia — Corah. 



109 



and also by LatonKBandra, which represents the group of tlie Corals. 



AstrcBidce conjluentes, so called because the separate calices run GALLEEY 



together into series as in the Brain Coral. X- . 



In the Bath Oolite the corals are of the same types, and ^ 



the chief reef - builder was Calamophyllia radiata. In the cases 1-6, 



Table- 

 cases 1-10. 



Fig. 164. — a, LatomcBandrcea Flemingii. M, Edw. Inf. Oolite: Somerset. 

 b, Montlivaltia trochoides, M. Edw. Inf. Oolite : Charlcombe. (Prest- 

 wich's Geology.) 



Coralline Oolite true reefs occur, and are formed of Thecosmilia, Oolitic 

 Thamnastr^a, and Isastrcea, of which large specimens are shown ^°^*^^- 

 in Wall-case 3 (Fig. 165<?, I). Beside these are some masses of ^^^^ 3 



Fia. 165. — a, T/iecosmih'a annularis, ¥lem. Coral Rag: Wilts, h, Isastraa 

 explanata, Goldf. Coralline Oolite. (Prestwich's Geology.) 



Isastrcea ohlonga, from the Portland Oolite of Tisbury, in which 

 the whole of the coral has been converted into chert. 



In the Cretaceous the corals were scarcer in England, for the 

 conditions were less favourable to their growth. In the Lower 

 Greensand there is a species, ITolocystis elegans, famous as it 



