Peanut Gallery - What variety of creationist is Buzsaw? (Minnemooseus and Buzsaw)

Buzsaw in message Message 71 wrote: But in general radiometric dating is not directly performed on the sedimentary rock, instead we date igneous rock which border the sedimentary layer. So to apply this to your analogy, we wouldn't date your stone wall we would date the floor/foundations it sat upon and the ceiling it is supporting. We can then infer that the stone wall was placed there between those two dates, and that the nail, which is analogous to a dead organism deposited at the same time, would also be placed in the same time frame. Unless you can describe a method by which the stone wall was put in place after the floor and ceiling were built (without the house falling down of course).As for index fossils, wikipedia has a good overview here. In general, organisms used as index fossils include corals, brachiopods, trilobites and other marine invertebrates (so no need to 'run' up hills to escape the water). These organisms would have been very widespread and easily fossilised with their calcium carbonate shells. These are examples of macrofossils used as index fossils, but there are also microfossils which are also used by the oil industry to identify the age of the rocks in the search for mineral resources.