A genus of larger Foraminiferida, which have a flattened, discoidal or lenticular test. They lived in warm, shallow, marine waters from the top of the Palaeocene to the Upper Oligocene, and in some areas they are numerous enough to be major rock formers. Many species have been described; they occur at different stratigraphic levels and in different facies associations. Nummulites planulatus, which is Cuisian in age, is often found in association with alveolinids and miliolids in a sandy facies; N. globulus occurs in the Ilerdian of the Pyrenees in marly and sandy facies; N. gizahensis is one of the largest forms and is usually found in sub-reefal limestones of the Upper Lutetian of the Tethyan realm; N. variolarius preferred shallow, calm environments and is found with miliolids in sandy limestones of the Middle and Upper Lutetian.
Subjects: Earth Sciences and Geography.