unknown sedimentary rock

This rock is made of fine grained crystals that can't be seen by the naked eye or with a hand lens. The rock feels smooth to the touch. In this specimen and in nature the rock is dominantly white or white-ish in color. While it doesn't appear like it, viewing this rock under a microscope will reveal a large amount of micro fossils helping create it. Because the hard parts of these micro fossils are comprised of calcite or similar minerals this rock reacts with acid effervescing as it dissolves away. The rock typicall doesn't taste salty. Because of it's dominance in Germany and western Europe the Cretaceous period, the latest in the Mesozoic, was named after the German word for this rock. Dr. Hugo Anderson-Whymark CC BYNC(4.0) via sketchfab [https://creativecommons.org/licenses/by-nc/4.0/legalcode]