0* erassolamellata -16- 
Original description: 
" General Description , A group of forms from the Marl 
presents the following structural characteristics : -- Corallum 
very mas 3 i Ye and large, with an irregular upper surface, which 
is convex in some parts, almost flat in others, and more or lass 
largely gibbous in all; inter oalicular groove very decided* 
Corallites usually very large, and never very small. Wall very 
delicate and indistinct; costae small; columella large# Septa 
variable in cyclical arrangement , the larger excessively developed 
at the wall and linear within# En do theca, abundant , but not in 
excess, vesicular. Exotheca not well developed, but decided and 
plentiful* Calices invariably found as casts: impressions prove 
them to have been shallow. Coenenchyma well developed. 
These characters , common to many forms, are more or less 
varied in intensity in different specimens. The septal number 
varies in individuals of the same corallum, in one series of 
forms to a remarkable extent, although the corallites thus differ- 
