Coal is found in sedimentary rocks, specifically in layers called coal seams. These seams are formed over millions of years from the accumulation and transformation of dead plant matter, primarily in swamps and bogs.

Here's a more detailed explanation:

* Formation: Coal forms in environments where there is a lot of plant growth, like swamps and bogs. When these plants die, they fall into the water and get buried under layers of sediment. Over time, the pressure and heat from these layers transform the plant matter into coal.

* Types of Rocks: Coal seams are found within sedimentary rocks, which are formed from the accumulation and cementation of sediments like sand, mud, and organic matter. These rocks often contain layers of sandstone, shale, and limestone alongside the coal seams.

* Location: Coal deposits can be found all over the world, but they are most commonly found in areas that were once covered by swamps and forests. These areas often have a geological history that includes periods of tectonic activity, which can bring the coal seams to the surface or closer to the surface where they can be mined.

Important Note: Coal is a fossil fuel, meaning it is a non-renewable resource. It takes millions of years to form, and we are using it up much faster than it is being replaced.