| A | B |
|---|
| fossil | preserved remains or evidence of a living thing |
| petrification | turning to stone; mineralization of organic matter |
| mold | fossil that shows the outward shape of an organism |
| cast | fossil showing the same shape of an organism |
| superposition | law that states that younger sedimentary rocks are above older layers |
| index fossil | fossil used to determine relative age of rock |
| unconformity | eroded rock surface much older than the younger rock layers above it |
| fault | break or crack along which rocks move |
| intrusion | igneous rock formation created beneath the surface |
| extrusion | igneous rock formation created on the surface |
