Rugose corals

The figure below shows the distribution of samples containing rugose corals.

Rugose corals are uncommon in the MRV strata.

Order Rugosa

Calcitic, solitary and colonial corals with major and minor septa. Major septa inserted serially in four positions; minor septa short and inserted between major septa, probably serially also. Tabulae almost always present; dissepiments commonly so. Axial structure present or absent, generally of septal origin. Walls formed by laterally fused septa, dissepiments, or additional stereoplasm; external walls epithecate.
M. Ord. - Perm.

Invertebrate Fossils, 179.