[neverevergiveup]

Actually, it's evidence of the ‘terra-cleansing’ that was being done by the same aliens that were terra-forming the Earth, and who had put dinosaurs on the planet in the first place. They wanted to make Earth more habitable for hominids, but the dinosaurs kept eating them, and thus the terra-cleansing. /s

[bigbob]

Or “6000 years”... /s