Minnesota River Virtual Tour - Kasota


Stop 9 - Kasota (River Mile 100)
Kasota Prairie Photo: Save the Kasota Prairie Purple coneflowers Photo: C. Henderson Kasota stone
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Near Kasota and again at Ottawa, towering limestone bluffs sweep up the sides of the river. Otherwise, the banks through Le Sueur, Henderson, Blakeley and on toward Belle Plaine are relatively gently sloping and clay covered. We’ve seen few signs of agriculture along the way. Instead, highway traffic noise, trains and the occasional distant hum of lawn mowers signal the more urban areas we’re headed to.
 
Stone Bluffs
In this stretch of the river, you can see ancient dolostone outcroppings that were exposed by the powerful waters of the glacial River Warren. Dolostone is a sedimentary rock very similar to limestone but composed primarily of the mineral dolomite. Mankato-Kasota dolostone is quarried from open pits near the town of Kasota. This very fine-grained yellowish-tan stone (photo, above) is relatively resistant to weathering and is widely used as a building stone. Many Minnesota landmarks are constructed with Kasota stone. The rock was formed 450-500 million years ago when a shallow sea covered most of North America. Burrowing marine organisms, most likely clams or shrimp, that moved through the soft sandy muds produced the mottled texture in these rocks. Geologists classify this sedimentary rock in part of the Oneota Dolostone Formation.

Prairies
Prairies historically dominated the Minnesota River basin. Early written accounts by explorers describe the prairies as vast, undulating seas of grasses stretching to the horizon. The Presettlement Vegetation Map summarizes vegetation patterns in the basin prior to 1850s. The map shows most of the basin covered with prairies while a tract of hardwoods called the Big Woods dominates the southeast corner. Intensive agriculture and other human activities have drastically reduced and modified the extent of native grassland and woodlands in the basin. In Minnesota, the seas of tall grass prairie once covered 18-20 million acres. Today, less than 1 percent (180,000 acres) remain. Some scientists describe the river corridor as a ribbon of native vegetation amidst a modified landscape.

Near Kasota, you can visit a prairie preserve—the Kasota Prairie (photo, above). This ninety-acre preserve is located on a rock terrace above the Minnesota River Valley. This site is in almost continuous bloom from the first pasqueflowers in April to the last gentians in October. There are many places in the basin where you can visit native or restored prairies. The western portion of the basin still has large tracts of prairies such as the 1,700 acre remnant in Big Stone National Wildlife Refuge.

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