Once our geologist had the “index fossil” that was found approximately in the same layer as the newly discovered fossil, he would then see where in the geologic column it came from and presto, he now had a date for his newly discovered fossil.
He would simply go to a chart that listed the geologic column by ‘ages’ and find the place where the index fossil appears, and thereby the geologists could tell the paleontologist how old his fossil was.
Carbon dating is used to determine the age of biological artifacts up to 50,000 years old.
This technique is widely used on recent artifacts, but educators and students alike should note that this technique will not work on older fossils (like those of the dinosaurs alleged to be millions of years old).
Levels of carbon-14 become difficult to measure and compare after about 50,000 years (between 8 and 9 half lives; where 1% of the original carbon-14 would remain undecayed).