Slightly off topic, but...
I digress, I don't know why I've been on this kick lately. Anything Prehistoric I just have to watch or read about.
Some of my favorite stories in certain franchises involve alternate history or incidents where some Dinosaurs didn't die (such as the semi-recent Doctor Who episode where they found some Dinos on a spaceship, Marvel's Savage Land or the Dinotopia novels when I was a kid). I've even used it as a basis of one of the alternate timelines in my story's setting (a parallel Earth where Dinosaurs never died out and some evolved alongside humans, some are still beast-like, and the entire world is very, very different).
When Jurassic Park first came out, I remember being very excited to read some articles that theorized what if different dinosaurs from different eras were to exist at the same time (picking specific types that would create a semi-harmonious ecosystem, which ones would cause others to be wiped out, etc.).