The limestone had formed in the clear salt sea of middle Devonian tropical Ohio. Eventually, the sea disappeared. Two eons later, ice slid over the limestone and, retreating, left a body of fresh water that included all of what is now Lake Erie and was twice as large. “We wouldn’t be able to feed this country the way we do if much of it had not been glaciated,” Anita said. “South of the glaciers, ancient kantoor per uur breda weathering removed soluble minerals and left a rather inert soil behind. After a couple of decades of planting, you need tremendous fertilizer additions there. This glacial stuff is full of unweathered mineral material-fresh-ground rock. And under it is limestone, which is what they put on fields. When early settlers came through here and saw no trees, they moved on to places like Missouri, beyond the glacial limit, and they missed some great farmland. In Egypt, they used to get fresh minerals with every flood, but those morons built the Aswan High Dam and stopped the floods. They’re starving themselves out and making a salt pan of the delta.” We were crossing the Findlay Arch and had reached the edge of the Michigan Basin, features of the subsurface structure, invisible and unexpressed in the black level surface of silts and clays. In tropical Ohio, the arch had at one time held back a large piece of the retreating sea. As the isolated water slowly concentrated and eventually disappeared, it left Morton’s salt and U.S. gypsum. It left even more limestone. It left dolomite, anhydrite-components of what is known as the evaporite sequence. North off the interstate, we went through Gypsum, Ohio, on Sandusky Bay, and on to the lake port Marblehead, where we boarded the Kelleys Island ferry. “VISIT HISTORIC GLACIAL GROOVES,” said a sign beside the ticket booth, and soon, for a stiff toll, we were beating into an even stiffer wind, which was kantoor per uur almere tearing the caps off the waves of Lake Erie. Kelleys Island is about four miles offshore, and other cars on the ferry were stuffed with a month’s worth of groceries. A hundred and twenty people live there, year around, on four and a half square miles, and as we drove across the island we passed stone houses with red and black boulder walls-jaspers and amphibolites plucked up by the ice and brought south from the Canadian Shield.