OREGON, USA — Imagine a time when travel in the Willamette Valley would have only been possible by boat because gigantic icebergs floated across the massive lake that stretched from the Columbia River all the way to Eugene.
Rick Thompson is a detective! Not of crime — but of Oregon’s geologic history. He’s on the trail of one of the region’s oldest mysteries: how hundreds of Montana granite stones have ended up in farm fields in Oregon’s Willamette Valley.
“They’ve been in the ground a very long time,” noted Thompson on a recent field trip into western Washington County. “Farmers usually plow or till them up and they’re often just sitting where the icebergs left them as they melted.”…