Dead snail is buried. Soft body decays. Almost all fossils are preserved in sedimentary rocks , rocks that formed when layers of sediment such as clay, mud, silt, or sand became compressed and hardened over millions of years. These types of sediments are laid down in lakes, swamps and oceans. This is one of the reasons why most fossils are the remains of animals who lived in or near the water.
Palaeontology is the study of ancient life.
Palaeontologists are the scientists who study the remains of ancient life - fossils and the rocks they are found in. In the Department of Palaeobiology at the ROM there are curators, assistant curators, and technicians. They are all palaeontologists whose job it is to care for the museum's collection and to interpret the fossil record.