Monday, October 05, 2009

In Plain Sight | Potholes

Slowly and quietly, the region's last glaciers melted away some 10,000 years ago. In most instances, they left behind the calm lakes and modest streams with which we are all familiar.

In a last great act of defiance, however, the glacier that created what is now the St. Croix River Valley stomped several dozen goofy footprints (called “potholes”) in the land. As ice receded into jagged outcroppings of the river gorge, glacial runoff often formed whirlpools with such force that they drilled downward though the rock below. Rocks and sediment swirling in these eddies acted like polish, carving smooth formations into the earth.

More than 80 of these funnels can be seen at Interstate State Park near Taylors Falls, the highest concentration anywhere on the planet. Many are partially filled with years of sediment, but the park also boasts the world's largest excavated pothole as well. A few at a time, visitors are welcome to navigate the narrow steps down into the ominously-named “Bottomless Pit” (pictured above). Of course in this case, “bottomless” means only 60 feet, but it’s still a humbling experience to stare up at the powerful forces which carved our home.

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