Helicosphaera gertae Bukry, 1981
Aubry, M. -P., Bord, D., 2009. Reshuffling the cards in the photic zone at the Eocene/Oligocene boundary. In: Koeberl, C., Montanari, A. (eds), The Late Eocene Earth-Hothouse, Icehouse, and Impacts. Geological Society of America, Special Papers 452, 279-301.
Bukry, D., 1981b. Pacific coast coccolith stratigraphy between Point Conception and Cabo Orientes, Deep Sea Drilling Project Leg 63. Initial Reports of the Deep Sea Drilling Project 63, 445-471.
Helicosphaera gertae
Bukry, 1981
Early Miocene