Fossils. . .

http://www.uncommondescent.com/intelligent-design/tiny-t-rex-from-china-and-other-animals/

It has been pointed out that circular reasoning is used to "date" fossils or strata. Strata is dated because of the fossils found within, while fossils are dated because of the strata they are in. Consequently, those fossils that are not found in the strata in which they ought to repose create a problem. See Morris, Henry M., 1974. Scientific Creationism, Master Books, pp. 95-96, 136.