Last time we were together, we explored the formation of the unique bedrock of downtown Thomson. We traveled in the time machine of science and saw 2-billion-year-old mud compressed into shale, then cooked and deformed about 1 billion years ago, turning into slate. Now it is exposed in the St. Louis River in Jay Cooke Park and lines the community of Thomson.

After that journey through time, I hopped into my Dodge Dakota, left Thomson, and traveled less than a quarter of a mile before I got distracted again, this happens often to me.

As I was driving over the St. Louis River on Highway 210...