Fusulinacea are an extinct superfamily of small to large, to very laurge, calcareous Foraminiferida. They were entirely marine sind made their first appearance near the end of Early Carboniferous time (Text-fig. 1). They thrived during Middle and Late Carboniferous and Permian time. During that 100 million year existence, they evolved more than 150 genera and more than 6000 species before starting a decline in the later part of the Permicm and finally becoming extinct near the end of that period. Members of the Fusulinacea became giants, typically reaching 1 cm or more in length, and some became enormous giants, reaching 4 and 5 cm in length in the mid-Permian, and a few as much as 10 cm! Not bad for a single celled organism. Fusulinaceans are usually large enough that field geologists can spot them quickly in their stratigraphic units.