Over the eons, layer after sedimentary layer of coccoliths created such landmarks as the White Cliffs of Dover. (discovermagazine.com)
They are covered in tiny plates of calcium carbonate called coccoliths, which fall to the sea floor when the organism dies. (palaeontologyonline.com)
But that was the time that the forefathers of the current planktonic coccoliths made the white cliffs of Dover and thick carbonate deposits in many other places. (realclimate.org)