It [chalk] forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells (coccoliths) shed from micro-organisms called co

It [chalk] forms under reasonably deep marine conditions from the gradual accumulation of minute calcite shells (coccoliths) shed from micro-organisms called coccolithophores. [1] Not that much different from anything we produce. When our active time as a species is over all of our leftovers will remain as a natural resource like everything else. [1] https://en.wikipedia.org/wiki/Chalk https://en.wikipedia.org/wiki/Chalk