Fossils are generally found in 

1. sedimentary rocks 

2. igneous rocks

3. metamorphic rocks 

4. any type of rock  

Fossils are generally found in dedimentary rocks, which are formed by the gradual deposition of slit, sand or calcium crbonate over millions of years in regions such as lakes or sea suring their formation, the dead animals ar carried to the sea or larger lake, sink down and get burried in the rocks, The animals, thus preseved in the rocks, are converted into fossils.