* Limestone: This is the most common type, formed primarily from the shells and skeletons of marine organisms like corals, mollusks, and foraminifera.
* Chalk: A type of limestone made up of the microscopic shells of marine algae called coccolithophores.
* Coal: Formed from the accumulation and compression of plant material (primarily trees) over millions of years.
* Oil shale: Contains organic matter derived from algae and other organisms.
* Diatomite: A fine-grained, siliceous rock formed from the skeletal remains of diatoms (single-celled algae).
Let me know if you'd like more details about any of these!