There are stromatolites of very obvious biologic origin (mounds of layered sediment and bacteria) very similar to stromatolites growing today in Australia, in rocks reliably dated to over 3 billion years old.
We don't have an actual Young-Earth Creationist sighting now, do we? It's always sort of cute and quaint when they pop up, don't see them too much anymore.
How can it be reliable if scientists consistently make the earth older and older (and I don't mean one year at a time). Scietists have said the Earth was millions of years old and not its billions. Next century, it'll probably be trillions.
The accepted number among us bugologist is 3.6-3.8 billion years.