Any kind of object clearly restricted to a specific point in the geologic column would do just fine.If green dice were found only in the middle Ordovician strata, they would make excellent "index fossils." Evolution should be seen as an explanation of the faunal succession, a succession which was worked out long before evolution dominated the scene. With a half-life of only 5730 years, carbon-14 dating has nothing to do with dating the geological ages! Hovind is confusing the carbon-14 "clock" with other radiometric "clocks." The only thing in the geologic record which has anything to do with calibrating carbon-14 dating is the coal from the Carboniferous Period.
Why should the percentage of lead to uranium in zircon crystals (the key to ordinary uranium-lead, radiometric dating) depend on which geologic period they are found in?
If most of the geologic column were created during Noah's flood, would it really matter whether a zircon crystal was found in Cambrian strata or Cretaceous strata, in Jurassic strata or Tertiary strata?
Once the worth of index fossils had been established on the basis of stratification studies, they could logically be used to extend the correlation of rock formations to other continents.
At this point in time they were simply a useful tool for correlating rock formations.
By then, the relative ages (order) of the geologic column had already been worked out in some detail.