Back when tropical Wisconsin had just started its journey northward from the equator, there were 15,000 foot high mountains here. Remember? No? How about the giant inland seas before that? If not, surely you recall the immense ice sheets that ground much of that rock into powder? That was only 10,000 years ago. Even if those events are not in your personal memory, the evidence of all those billions of years — yes, that’s billions with a “b” — of history are all around you. Thanks to the foresight of Wisconsin conservationists, much of that evidence is publicly accessible in Wisconsin State Parks. Science writer Scott Spoolman explores that history in his new book, “Wisconsin State Parks: Extraordinary Stories of Geology and Natural History,” available now from the Wisconsin State Historical Society Press. Scott joins Eight O’Clock Buzz host Brian Standing by phone.