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| Fossil-filled flagstones lead to a vista overlooking the Mississippi River. |
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| Buena Vista Overlook Trail topo map |
The 0.22-miles round trip Buena Vista Overlook Trail marks a must-see for anyone traveling the Wisconsin side of the Mississippi River. Located in Buena Vista County Park, it’s an easy walk that will leave you awed.
To reach the trailhead, from Wis. Hwy. 35 in Alma, turn east onto County Road E; known as North Street in town, it curves and becomes Second Street then curls again as ascending the bluff. Near the top, turn left/north onto Buena Vista Road. The road dead ends at the park entrance atop Twelve Mile Bluff.
Take the trail heading west from the parking lot’s west-central side. It passes a lawn with picnic tables on its way to the vista.
About 490 to 420 million years ago, this part of Wisconsin sat at the bottom of a shallow tropical sea no more than 20-30 feet deep. As sediment high in calcium and magnesium settled on the sea floor, it cemented together and hardened into dolomite. Today, that seafloor sits more than 1040 feet above sea level.
The Prairie du Chien dolomite caprock rests atop sandstone set down more than 490 million years ago. Because of the caprock, the bluffs here remain in place, though rain, freezing/thawing, and wind continue to erode away the sandstone grain by grain.
The flagstones for the walkway leading to the vista were cut from the caprock and contain fossilized animal burrows. Little is known about the creatures who made these burrows, but they are thought to be soft-bodied worms that lived just beneath the sea floor. Small, fossilized shells also can be found in the flagstones.
Stromatolites ranging a foot to two feet in diameter sit on the caprock at the vista. These rock formations were created when cyanobacteria, which photosynthesize light for food in warm, shallow waters, die and grow atop one another, building a boulder layer by layer.
From the vista, the city of Alma spreads out below, and to the northwest Lock and Dam No. 4 runs the length of the Mississippi River. The opposite shoreline is Minnesota.
Those looking for a physical challenge can instead leave their vehicle parked in Alma and head up the steep Buena Vista Trail. From Second Street, the route climbs 550 feet of the bluff over three miles to the park’s lawn area.
Learn about trail guidebooks available in the Hittin’ the Trail series.
