The Cycloclypeus assemblages in the Philippines are confined mostly to Miocene formations. Cycloclypeus carpenteri Brady, is the only known species that has probably survived up to Pliocene. Associated with the assemblages are various forms of mega- and microfossils which are mostly small and lager foraminifera, corals and calcareous algae.

Out of the 400 thin sections of rock samples examined, almost 200 contained Cycloclypeus. Aside from these thin sections, polished rock samples were also studied.

The greatest number of Cycloclypeus species are in limestone areas presumably because they could not withstand the condition in other localities.