calcareous plates from Coccolithophores.

Microscopic structures of varying shape and size that are made of calcite, are secreted by calcareous nannoplankton, and are found in marine deposits from the Triassic period to the Recent. Coccoliths range in size from one to thirty-five micrometers in size.

minute calcium carbonate platelets secreted by coccolithophores which bear them as surface plates.