Rugose corals

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

[ rugose coral distribution ]

Rugose corals are uncommon in the MRV strata.

[ rugose coral ]

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.