300 Foxes and a Donkey's Jawbone
Statements that the Earth had a uniform equable climate during geological periods are a little misleading. Sediments are assigned to periods based on their flora and fauna, to it's just a little microcosm of circular reasoning.
"Mosses, lycopods, sphenopsids, ferns, seed ferns and cordaites." The next part of the description we have of the Pennsylvanian is a laundry list of plant kinds which sounds like an ecosystem or habitat, not a period of time.
Most of the sedimentary deposits assigned to the Mississippian are coal beds in the Mississippi valley. The coal is the remains of swamp habitat that was buried in a world-wide flood.
The Triassic is another microcosm of inductive reductive circular reasoning that we may wryly refer to as an "eddy in the space-time continuum." It's a tip of the hat to Douglas Adams, author of the Hitchhiker's Guide to the Galaxy.
We (me and the Holy spirit) can't avoid the obvious conclusion that Mississippian sediments are the remains of an ecosystem which was buried in a flood.