I'm not gonna be boring about this, I'm not suggesting a weather system, more so the creatures and things around it. I'm unsure as to whether or not this is already the plan, but couldn't find anything on the first few pages of the wiki.
What I mainly wished to suggest was once the tar pits are emptied, you'd find mammal skeleton(s) of some sort within the pit. Perhaps some tool to aid in extracting fossils from the pits? I'd also like to suggest a byproduct of the tar. Asphault. Created by combining the tar, sand, and gravel in the crafting grid, and once placed it produces the road like substance we know today!
Thank you for your time!
I had issues creating an account, so I'm posting as an anonymous user atm.