Sedimentary rock

Sedimentary rocks are formed from layers of sediment (naturally occurring materials, including shells, sand, mud and pebbles) that drop to the bottom of lakes or seas and are compacted in layers over millions of years. Examples include limestone and sandstone.

Sedimentary rock is formed into layers from naturally occurring materials such as fish remnants, sand, mud etc. These layers are compressed that then become solid, such as sandstone, shale, mud stone — Imagine a cemetery (sedimentary) for shellfish at the bottom of the ocean where the gravestones are limestone that has formed over the years from the shells deposited on the bottom.