* Coal: Formed from the accumulation and compression of plant matter, primarily in swampy environments.
* Limestone: Primarily composed of the calcium carbonate shells and skeletons of marine organisms like corals, clams, and foraminifera.
* Chalk: A type of limestone made almost entirely from the microscopic shells of marine plankton called coccolithophores.
* Diatomite: Formed from the accumulation of diatom skeletons (single-celled algae with silica shells).
* Oil shale: Contains organic matter from algae and other organisms that has been transformed by heat and pressure over millions of years.
* Fossiliferous limestone: Limestone containing visible fossils of shells, bones, or other remains of organisms.
These are just a few examples, and there are many other biogenic sedimentary rocks depending on the specific types of organisms involved and the environmental conditions.
