A fossil is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the fossil record.
Permineralized bryozoan from the Devonian of Wisconsin
External mold of a bivalve from the Logan Formation, Lower Carboniferous, Ohio
Silicified (replaced with silica) fossils from the Road Canyon Formation (Middle Permian of Texas)
Recrystallized scleractinian coral (aragonite to calcite) from the Jurassic of southern Israel
A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer usually created by an animal or organism that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washed up on beaches by beachcombers. The shells are empty because the animal has died and the soft parts have decomposed or been eaten by another animal.
Seashells washed up on the beach in Valencia, Spain; nearly all are single valves of bivalve mollusks, mostly of Mactra corallina
Hand-picked molluscan seashells (bivalves and gastropods) from the beach at Clacton on Sea in England
A group of seashells, mostly bivalves in the family Pholadidae
Mixed shells on a beach in Venezuela
