* Formation: Sedimentary rocks are formed from the accumulation and cementation of sediments, which can include the remains of plants and animals. These remains are often preserved within the layers of sediment.
* Heat and Pressure: Metamorphic rocks are formed when existing rocks are transformed by heat and pressure. These conditions often destroy any existing fossils. Igneous rocks are formed from the cooling and solidification of molten rock (magma or lava), which would also destroy fossils.
While it's possible to find fossilized remains in rare instances within metamorphic or igneous rocks, the process of their formation typically makes it much less likely.
