Hiking around the Black Hills for many years, Mr. RR and I have found several fossils. Some have tropical flora in them and many have sea critters, snails, clams etc.
Apparently, this was a tropical zone at one time.....before man came along.
There was also an Ice Age here, millenia ago. In the southern Black Hills, there is an archeology mammoth dig. They continue to find ice age skeletons. It’s a fascinating place to visit.
Thanks for the tip on visiting the Black Hills, I'd like to take my grandkids there. I was helping one last week with a play archaeology set I bought for her that had her chiseling away a cast brick containing "gem" stones. She loved doing that.