Removing a Pleistocene headache

Brookings County Now & Then

Posted

It was a Pleistocene.

Now, I guess, it’s a Prussman.

Actually, it’s just a rock, albeit a rather big one.

It weighs more than a school bus.

It took millions of years to get this far down on the ancient and wide glacial highway that formed the 200-mile by 100-mile Coteau des Prairie on which we all languish.

About 20 years ago an SDSU economics professor, the late Dr. Rocky Gilbert, was speeding down Interstate 29 on his motorcycle at about the Colman exit.

He saw someone on a dozer in a field digging a hole. Next to it was a very large boulder. It was just what a guy nicknamed Rocky was looking for to embellish the front yard of his home at the corner of Sixth Avenue and Eighth Street.

He drove into the field before the farmer was able to perform the last rites on what geologists call a glacial erratic. 

The erratic slid south encased in glacial ice from what is today Manitoba, Canada. Its ride was probably on the mile-thick glacier known as the Wisconsin Drift that crept along a few meters a year, scooping up whatever was in its path or below its path.

Its journey to that Moody County field started during the Pleistocene Epoch.  

So about 1.8 million Pleistocene years later it landed in Moody County and Rocky bought it, paying somewhere between $800 and $1,000. He then called Al Gregg’s Dakota Service in Brookings, a firm specializing in handling big, heavy rigs and similar tasks, although there’s nothing on Al’s business card about hauling large rocks.

But Al accepted the challenge. Using a tilt-bed trailer and some railroad ties, Al and his crew nudged the boulder aboard the trailer and delivered it to Rocky’s house at 804 Sixth Ave. 

After some head scratching and fancy maneuvers, the 17-ton boulder was winched into place. This month, the home’s new owners decided the rock just didn’t fit into their landscaping plans.

Gregg had long ago washed his hands of glacial erratics, but the Prussman Contractors picked up the cudgel. Using a 30-ton crane, they wrapped the rock in straps and loaded it on to a big trailer. 

It was hauled to the Prussman glacial alluvium, a.k.a. sandpit, south of Bowes Construction Company at 2915 22nd Ave. S., where it will probably remain forever. 

Interestingly, the original location of the boulder in Moody County south of Brookings is an area where the mile-high glacier started to melt. As it did, it dropped tons of alluvium, thousands of fieldstones and a few giant boulders as it retreated north.

The granddaddy of those few glacial erratics (the big ones) in that area is what is known as Lone Rock in eastern Moody County on Highway 34.

That house-sized boulder sits in ponderous repose in a cow pasture. It measures more than 25 feet high and 40 paces around and is estimated to weigh in excess of 100 tons, but that’s just the visible part above ground.

There are three “little sisters” Erratics related to Lone Rock and now the Prussman Rock, in a field 1 1/2 miles south of Highway 324 south of Aurora. The “little sisters” are bigger than the Prussman rock, by the way.

All of us are living on this broad field of glacial deposits so perhaps there’s one buried in your front yard. But don’t call Lyle Prussman or Al Gregg to haul it away.

As you might surmise, moving a glacial erratic is one big Pleistocene headache.

So call Manitoba. Tell them to come down and get their darn rock.

If you’d like to comment, email the author at cfcecil@swiftel.net.

Courtesy photo