It took a lot of algae shells to make a chalk deposit, and one finds fossils of bigger organisms in them, and the flints/cherts where silicates ?condensed? during lithification. But where did the non-shell parts of the coccoliths go? Did currents separate the calcite from the organics? If they decomposed in place, didn't that leave the organic carbon of the decomposers? Was it fluid enough to squeeze out during lithification? Is this happening somewhere currently?