The area that’s now KC was underwater 300 million years ago. So reminds Kansas City Millions of Years Ago: What the Rock Record Tells Us, an exhibit at the Box Gallery (1000 Walnut, first floor of the Commerce Bank Building). The history lesson runs through April 26, but visitors can get a free personal tour with Richard Gentile, professor emeritus at the University of Missouri-Kansas City and curator of the UMKC Geosciences Museum. He leads groups at 11 a.m. and 2 p.m. The gallery is open 8 a.m.–8 p.m.; see theboxgallery.org.