The lost oasis

-By Cindy Votruba
Independent Staff Writer

MARSHALL - Glacial lakes and rocks, sloughs, ditches, lake basins, tall prairie grasses comprised the Murray County terrain for more than a billion years. Now, most of those lake basins are drained and the tall prairie grasses are almost gone.

Southwest State University professors Tom Dilley and Doug Spieles made the presentation “The Terrain of Murray County from Till to Tile” at the conference “Draining the Great Oasis: A Colloquium on Environmental History” Thursday at the college.

Dilley said the rocks of Murray County can tell about the growth of the region. That includes granite from more than three billion years ago. From one billion to three billion years ago, mountains were in existence, Dilley said. “Mountains get built over tens and tens of billions of years, they don’t happen overnight, give or take an earthquake every 100 years, lift the land up a foot or two,” Dilley said. “It doesn’t take long, it’s something that happens once every 100 years, 10,000 times.” Mountains are growing right now, Dilley said, in the Alaskan range and the Andes. He said that it takes hundreds of million of years for those mountains to erode away.

The next important rock unit was the Sioux quartzite,“the famous red rock of southwestern Minnesota,” Dilley said. “You see it as it’s quarried extensively, you see it as building stone in many of the churches around the area, in county courthouses and other buildings,” Dilley said. “You find it exposed at the surface at Pipestone, at Blue Mound, at Jeffers, at Jasper Quarries.”

The next youngest rock unit is opened by erosion, Dilley said. “Here in Murray County, we have to skip ahead to the ‘dinosaur days,’” Dilley said. “Relatively recently, only about a 100 million years ago to 65 million years ago.” All of the continents were grouped together as Pangea. When they separated, Dilley said, North America contained the Western Interior Seaway, a vast inland sea. A lot of marine reptile fossils were found in Kansas and Nebraska. “This underlies Murray County, we can again, go down and find this stuff,” Dilley said. “It’s not uncommon to find sharks teeth and clam fossils and coral fossils scattered through the glacial till throughout here, where the glaciers dug up this rock unit and now those fossils are part of the glacial material.”

Fast forward to the 1800s when European settlers started coming to the area, said Spieles. “Joseph Nicolette, one of the early explorers to come through this area described this area as elastic prairies dotted with small shallow lakes,” Spieles said. “This area is what we call in wetland circles, ‘the prairie pothole region.’” Murray County has 100 lake basins, Spieles said, all of which are shallow. “The largest lake in Murray County, Lake Shetek, on a rainy, humid day, it might be 10-11 feet at the deepest,” Spieles said.

But what was most interesting to Spieles about Murray County were the sloughs — small emergent marshes. This region was important to waterfowl, he said. “About an estimated 50 to 75 percent of the waterfowl in North America are produced in the prairie pothole region,” Spieles said.

The prairie pothole region was also an area that saw an abundance of muskrats, Spieles said, which wasn’t prosperous for the fur trading industry. “A lot of early European-American settlers came here because of the fur trade,” Spieles said. “They were interested in other animals that were a lot more valuable, but we didn’t have a whole lot of those animals here. What I’m mainly talking about beaver, mink and otter.”

The later settlers were looking for land to build a homestead, Spieles said, and what they found was tall grass prairie. “So if you farm this land, what are you going to do about all this water,” Spieles said. “You can’t grow a whole lot of crops in standing water.” These sloughs made great farm land, Spieles said, and to get the water off the land, the farmers needed ditches. “And then came tile after the ditches,” Spieles said. “But the ditches came first.”

In 1849, the Swamplands Drainage Act was passed, Spieles said, which passed almost millions of acres of wetlands from the federal government to the state. Drainage began in earnest around the 1880s, he said. The ditching was rampant in Murray County, Spieles said. “By 1920, there was 78 miles of ditch, and today we have over 100 miles of drainage ditch,” Spieles said.

About two-thirds of the 100 lake basins have been drained entirely or affected some way by a drainage ditch or by tile lining, Spieles said. It’s not easy to restore a wetland to its natural state, Spieles said, especially when you don’t know what it was originally like. --