- CORONA - The mystery starts
with, of all things, Play-Doh. By using the clay-like children's plaything
in a demonstration, Judi Rudebusch aims to make a point. She plunges the
pointed end of a four-sided star drill bit into the Play-Doh and twists
it. The hole, of course, is round. Then she sticks the edge of a chisel
into the Play-Doh to show how it leaves a hole with edges.
- The point of the exercise is to show the difference between
round-cut holes and the edged holes that have been been found in hundreds
of other rocks throughout the upper Midwest over the years and have spawned
all kinds of historical theories. It's also the same type of hole that
Rudebusch has found in rocks around Wilmot and Corona. Lay a quarter next
to one, and one can see the difference in shape.
- And not just one rock or a few. She's found them in 52
rocks throughout the Whetstone Valley.
- "Those holes are there for a reason. What does it
tie into?" she asks rhetorically.
- It wasn't a hole in a rock that got Rudebusch interested
in this mystery. Rather, it was a horn.
- When she was young, Rudebusch played near her dad's house
and remembered coming across a rock with an unusual look to it. A few years
ago, she went back to the land to look for the rock. There it was: a chunk
of granite peeking out of the weeds, with an indentation right on top.
The marking looks to be in the shape of an animal's horn. It could be water
erosion, but erosion would normally go all the way down the rock. The indentation
curves north at the end.
- Piqued by the uniqueness of the shape, Rudebusch contacted
Marion Dahm of Chokio, Minn. Dahm has spent the last few decades seeking
out unusual markings and holes in stones across the upper Midwest. He came
over and was excited by what he found. He also told Rudebusch to go search
the hillsides of the area for more unusual markings.
- Sure enough, Rudebusch began to find rocks with the triangular-shaped
holes in them. In her first year of searching the fields around the Corona
area, she found 17 rocks with similar indentations. More came as more people
began to tell her of similar indentations on their properties. As the number
grew, so did her interest.
- "I just want to keep finding more," she said.
"I wanted to see what the next one looked like." The discoveries
have more in common than just a certain type of hole shape.
- The elevation of each rock is estimated to be between
1,150 feet to just over 1,200 feet. The rocks are usually deep in the ground
and on the side of a hill - away from flat, farmable land. The holes themselves
are not exact sizes, ranging from around 3/4 inch in diameter to 1 3/8
- As mentioned earlier, there are hundreds of rocks with
similar holes across the Great Plains. With the discoveries have come the
theories as to why the holes are there. A popular theory is that the holes
were drilled to insert dynamite to blast the rock apart.
- But here is where the questions start coming up for Rudebusch.
From her research, dynamite was about 1 1/2 to 2 inches in diameter - too
big to fit in the majority of the holes found. When making holes for dynamite,
a star drill was used, which makes a round hole, not one with edges. Plus,
a common way of blasting rock in this area was by a process called mudpacking.
Farmers would lay one or two sticks of dynamite on the rock and cover it
with mud, then light the fuses.
- Then there's the location of the rocks themselves that
make that theory cloudy.
- "There wouldn't be a real good reason to go out
of your way to move them," said Rudebusch.
- Another theory was that holes were cut into the rocks
to make foundation stones. But according to people that Rudebusch has talked
to who know about how things like that are done, a number of holes are
cut into a rock to make foundation stones - a better edge is made that
- The rocks Rudebusch has found have a single hole. Yet
another theory is that holes were made for geological core samplings. But
the device used to make them has a round tip, and wouldn't leave edges
on the inside of a hole.
- One theory that Rudebusch said would be easy to assume
is that the rocks were used as mooring stones.
- The rumors of mooring stones have been around the upper
Midwest for decades. Legend has it that during the first half of the last
millennium, ancient Vikings made their way into what is now the Great Plains
and set up settlements. They cut holes in rocks near waterways to establish
poles in to tether their ships to.
- It's an assumption that has flared up again with the
recent discovery of a rock near Kensington, Minn., that may bear inscriptions
written in ancient Scandinavian lettering. That area is already famous
for the Kensington Runestone. The stone, supposedly discovered in 1898,
has etchings on it that some people think tell a story of the deaths of
Viking explorers in west-central Minnesota in the 1300s.
- That theory has never been proven and has its fair share
of nay-sayers in the archaeological community.
- Even with three years of walking fields and tons of research
to go on, Rudebusch said that she isn't subscribing to any particular theory
on what the holes represent.
- "There's not enough evidence to firmly sew down
any theory," said Rudebusch.
- A geologist from Vermillion came out and looked over
the stones on Monday, and he determined that if nothing else, the holes
definitely were not made naturally. Rudebusch said that more geologists
are on the way, and that she's been in contact with the state's archaeological
- It is a consuming hobby for Rudebusch. She said she doesn't
possess the background to try and prove this. It's not a cultural thing
for her. It has more to do with her enjoyment of history - and the mystery
that these rocks present.
- "It just swallows you up," she said. "It
does wake you up in the middle of the night, thinking."
- ©Watertown Public Opinion 2001