From CreationWiki, the encyclopedia of creation science
Index fossils are those used to identify a particular layer of the geological column. Many fossils are found above or below other fossils. This sorting of fossils poses a particular challenge for creationists to explain through flood geology.
Marine fossils are a preferred index fossil as can be seen in the following U.S. Geological Survey diagram. Marine fossils are abundant in the fossil record and can be found in every single layer of the geological column.
See Also