Radiometric dating is based upon the scientific principle of
One can hardly accuse these pioneers of evolutionary prejudice.
Nearly a half-century would pass before Darwin's book, The Origin of Species, was published!
The principle of faunal succession in the geologic record was established by direct observation as early as 1799 by William Smith.
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.
(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!