Fusulinid

The fusulinids are an extinct group of foraminiferan protozoa. They produced calcareous shells, which are of fine calcite granules packed closely together; this distinguishes them from other calcareous forams, where the test is usually hyaline. Their fossils are so abundant that they have formed entire limestone formations. The fusulinid Cottonwood Limestone formation in Kansas is an example of this. Fusulinids are important indicator fossils.

Fusulinids appeared late in the Mississippian Period. They were a part of the Carboniferous and Permian marine communities. They are excellent guide fossils for Pennsylvanian and Permian rocks. However, fusulinids became extinct at the end of the Permian Period.

Fusulinida フズリナ