[allmost]

65 million years is a rather extraordinary extrapolation. Science used to be testable.

[wendy1946]

We do not have any plausible evolutionary antecedents (on this planet at least) and even if we did, they could not plausibly have come from Africa.

The Basic Non Evolution of Modern Man

Other than that, the thing about the 65M years has turned out to be bullshit (all the blood and raw meat turning up in dinosaur remains recently):

[BroJoeK]

allmost: "65 million years is a rather extraordinary extrapolation. Science used to be testable."

Radioactive decay rates for dozens of different materials are tested and known.
So Radiometric dating can be used to establish and confirm ages of ancient events.

The approximate age of 65 million years for the Cenozoic Era is not in doubt, scientifically.