| A | B |
|---|
| fossil | Any remains or trace of a formerly living organism preserved by natural processes. |
| paleontology | The study of fossil animals and plants. |
| index fossil | A type of fossil that seems to appear reliably in its proper evolutionary and stratigraphic sequence around the world according to old earth paleontology. |
| transitional form | A fossil of an organism that supposedly shows a step in the evolution from one distinct kind of organism to an organism higher up on the evolutionary tree; "missing link" |
| extinction | Disappearance of a fossil form from the geologic column in more recent strata (secular paleontology) |
| fossil fuel | A natural energy source that is believed to have formed from fossilized organisms. |
| coal | A metamorphic, organic sedimentary rock formed from fossilized terrestrial plant matter. |
| lignite | Dark brown, soft, crumbly coal that is aboutn 30% carbon and includes liquid organic substances; can contain fibrous fossilized plant matter. |
| bituminous | Moderately dense, hard coal that is dark brown to black in color and is about 70% carbon, contains most energy per gram of any type of coal. |
| anthracite | Densest and hardest form of coal that is very dark and is more than 90% carbon; burns with the hottest and least smoke filled flame of any form of coal. |
| petroleum | Crude oil as taken from the ground; traditionally known as a liquid fossil fuel made of decomposed fossil marine organisms. |
| natural gas | A gaseous fuel often found with petroleum, consisting mostly of the organic gas methane. |
