The hollow space that is left after an organism's remains dissolve.
The age of a rock in years.
A fossil that lived in many places around the world for a short period of time; it can help scientists find the age of a rock layer that may be out of order.
Scientists who study fossils and compare them to living things today.
A type of fossil formed when an animal's footprint hardens in sediment.
The age of a rock compared with ages of other rocks.
A type of fossil formed when minerals may slowly seep into the remains of living things, such as wood, and harden into a rocklike fossil.
A thin coating of carbon that is left behind by a living thing.
The preserved remains or traces of past life found in some rocks.
Hardened tree sap; can preserve a whole animal
One huge landmass; all of the current continents were together.
A type of fossil formed when minerals fill the space left after an organism's remains dissolve.
The type of rock where most fossils are formed.
Where would you find the oldest fossils
millions of years
some animals haven't changed
When fossils of water creatures are found in land areas, you know the area was once. . .