About Fossils

For in-depth information on specific fossils look at the table labeled "Pages about fossils"

If you want to buy fossils try this: Fossils For Sale

Fossils are inherently interesting. The form of a living thing cast in stone inspires curiosity. What was it and how did it turn into stone? How long did it take? What was it like when this thing was alive? What did it eat?

To begin a fossil can belong to one of two categories:

• Type I-the remains of the dead animal or plant or the imprint left from the remains.
• Type II- something that was made by the animal or plant while it was living, like a footprint or a burrow or its poop (coprolite)!

Type I Fossils include bones, teeth, skin impressions, hair, the hardened shell of an ancient invertebrate (an animal without a backbone) like a trilobite or an ammonite, or the impression of an animal or plant, even if the actual parts are missing.

Type I fossils can be the actual thing that it once was, like a piece of bone or hair or feather. More often the bone material is replaced by different minerals contained in the liquid of the sediments that buried it. What was once bone is now some sort of crystal.

This process also takes place with shells, exoskeletons and wood. If the spaces in the bone are filled with liquid minerals which later harden it is called Permineralization.

Sometimes the organic material is dissolved by the mineral-laden water. The process happens so slowly that each cell is dissolved and replaced by a particular liquid mineral before it hardens. This is called petrification. In petrification, every detail down to the cellular level is duplicated in the minerals.

Type I fossils can also be molds or casts of the original animal or plant part. If the original organism decays, leaving an imprint and an empty space, it is called an exterior mold or simply a mold. If a space in the structure is filled with minerals and then the original animal or plant part dissolves, it is called a cast.

There are many ways that fossils are formed. Freezing, drying, carbonization, and Permineralization are some of the processes that create fossils. To read more about fossilization processes see fossil formation