The chalk itself's composed by plankton which has fallen down from the sea surface onto the sea floor, so that 90 percent of the sediment here is skeleton of living stuff, and then you have that millimeter-thick red layer, and then you have black rock.
Kalken selv er sammensat af plankton der er sunket ned fra havoverfladen til havbunden, således at 90 procent af sedimentet her er skelettet af levende ting, og så har man det millimeter-tykke røde lag, og så har du sort klippesten.