When I lived in Nebraska I wass fascinated by the evidence from ash pits of a tropical climate in this plains state. There is a wooly mamouth in the state museum and other animals associated with jungles. Then they found evidence it was once a pine forest.
Petrified trees found in North Dakota were Sequoia, iirc. >4 ft. dia. stumps are pretty common.
I thought woolly mammoths were a cold climate animal.