Dating and correlating rock layers
It's just one of the tricks that have been used to make the work a little more precise. I believe he has confused the use of index fossils with evolution.
Nearly a half-century would pass before Darwin's book, The Origin of Species, was published!Evolution, working in tandem with geologic ages, can explain why we have index fossils, but evolution is needed to make the index fossils useful for dating strata.While we're on this subject, you might wish to know the odds of arranging the Precambrian era, the seven geologic periods of the Paleozoic (Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian), the three periods of the Mesozoic (Triassic, Jurassic, Cretaceous), and the two periods of the Cenozoic (Paleogene, Neogene or Tertiary, Quaternary) in their proper order by pure chance.Noah's flood might just as easily deposit the same crystal in one place as another. Pressure has nothing to do with it, and zircon crystals all have about the same density as their total lead content is small.Just what is it that a Cambrian stratum has which a Cretaceous stratum lacks?(Far from being a rubber stamp, radiometric dating would go on to revolutionize our understanding of the Precambrian.) Thus, it became possible to date strata directly from index fossils.
Note that evolution has nothing to do with how the index fossils are used to date strata!
One would think that the flood sediments (gathered from the four corners of the old antediluvian world) and their associated igneous rock (formed during the flood) would all register very little radiometric age.
At the very least we would expect random fluctuations if the radiometric methods were totally at sea.
Studies done on the European continent soon demonstrated the universal validity of index fossils.
That is, an index fossil corresponded to a very specific point in the geologic column.
Then the paleontologists use the geologists' dates as evidence for the age of the fossils! The relative order of the strata was first determined by the principles of stratification. Beagle, a very strong Bible believer, made it a point to have a copy of Lyell's book for the ship's library.