James E. Conkin, Barbara M. Conkin, James W. Pike; Mississippian foraminifera of the United States; Part 2, The Hannibal Formation of northeastern Missouri and western Illinois. Micropaleontology ; 11 (3): 335–359. doi:
This fauna described from eight localities in Missouri and five localities in Illinois, consists of 30 species (one new and five unidentifiable) belonging to 15 genera and 7 families. The genus Blastammina Eisenack, 1932, is recognized outside the Baltic region for the frst time, and its age extended into the Lower Mississippian. The age of the Hannibal Formation is definitely Kinderhookian on the basis of arenaceous forams. Its fauna, although similar to that of other formations in northeastern Missouri and western Illinois, is most closely related to that of the Northview Formation of southwestern Missouri.