Nummulites nummularia; Print; A nummulite is a large lenticular fossil; characterized by its numerous coils; subdivided by septa into chambers. They are the shells of the fossil and present-day marine protozoan Nummulites; a type of foraminiferan. Nummulites commonly vary in diameter from 1.3 cm (0.5 inches) to 5 cm (2 inches)and are common in Eocene to Miocene marine rocks; particularly around southwest Asia and the Mediterranean (e.g. Eocene limestones from Egypt). Fossils up to six inches wide are found in the Middle Eocene rocks of Turkey.