We can be certain that Job was a contemporary of Abraham. This means that when Job describes God overturning mountains, he's recounting something that happened recently, about 200 or so years before him.
Abraham and Job
Dinosaurs Abundant
According to our compilation of doublespeak terms used in Paleobotany and Paleontology "abundant" is a euphemism for eradication. That's what Jurassic sediments preserve: the eradication of dinosaurs.