Coccolithes is patches tiny limestones in the shape of record secreted by seaweeds haptophytes. Certain number of coccolithes puts together to train a called sphere coccosphère. The body (the seaweed) which secretes the coccosphère is a coccolithophore (or coccolithophoridé) which belongs to the marine phytoplankton.
Coccolithophores appears in Sorted out and are still very active nowadays. They are the main calcareous nannofossiles (Bown and Young)


Coccolithe and coccosphère, seen in the electron microscope

Schéma de l'organisation interne d'un coccolitophore, repris de Bown,P.(Ed.), 1998

Their study can be made in the microscope pétrologique, in contrast of phase or in clear bottom, or better still in the electron microscope with sweeping.

Zonation calcareous nannofossiles of the upper Cretaceous according to Perch-Nielsen (1985)