From The Sunbury News, February 4, 2016:

Because You Asked . . . .

    Sunbury's Glacial Boulders

By Polly Horn, Curator of the Myers Inn Museum

An undated historic photo of Ohio's largest glacial boulder, know as a crystalline erratic, is located two miles east of Sunbury and one tenth of a mile north of Hartford Road.  It rests on private property but can be seen in the winter when there are no crops in the field west of it.

Salt water fossils found along the Big Walnut Creek at the edge of Sunbury take our history back to the shifting of the land plates which led to the formation of the continents as we know them today. With the passing of geologist Lloyd Volk, I lost the ability to find these fossils but they are there if geologists care to hunt.

However, the glacial erratics are much easier to find so we know more about our history during the Pleistocene Epoch or "Ice Age" when three-fourths of Ohio was covered with massive sheets of ice often a mile deep.

This is extremely difficult to imagine sheets of ice a mile thick slowing moving across Canada and into Ohio. When each of the big sheets of ice melted, they left materials behind which had been picked up in its path. Little stuff washed away but bigger boulders found new homes.

I remember a picture of the big rock in our 4th

White is the area of Ohio covered by glaciers.

grade geography book which said it came from eastern Canada. Decades later I learned it did not match eastern Canadian mountains. According to the late Lloyd Volk it was brought to Ohio from western Canada during one of the many glaciers. This large, oval-shaped granite boulder is 22 feet long, 18 feet wide and 8 feet high with a circumference of 72 feet. The weight of the exposed portion of the erratic is about 200 tons. The portion of the boulder below ground level is unknown. At one time a property owner considered cutting the boulder for cemetery markers but it was too massive and difficult to be profitable.

Folklore says the rock takes 32 men standing shoulder to shoulder to make a ring around it. But the actual size is noted in a 1984 bulletin from Ohio Department of Natural Resources.

When the Statue of General William Starke Rosecrans was being funded, a member of the Rosecrans Headquarters group of the Big Walnut Area Historical Society found a glacial erratic on private property in Franklin County and got permission to move it to Sunbury. Geologist Chuck Grapes said. "

This glacial erratic was brought to central Ohio from northern Ontario by the Wisconsin glaciers from 110,000 to 10,000 years ago. It is an igneous rock formed from ancient volcanic magna 2.5

As glaciers melted back trees began to grow and mastodon's roamed this area billion years ago." In 2012 it was moved using two crane companies to Sunbury Square for the 

base of the Rosecransí Memorial on Sunbury Village Square.  It weighs 20 tons and is one of the 5 largest glacial erratics in Ohio.

Both glacial erratics are featured on the Ohio Historical Marker in front of the General Rosecrans statue dedicated in September 2013.

Photo at right shows shows Alum Creek looking north from the bridge in 1928.  The rock formations and melting of the glaciers left deep creek beds along the Big Walnut and Alum Creek.  While some of this shows in 2016, Alum Creek Reservoir covers much of it.

Photo Credits:

Boulder photos from Community Library and BWAHS files.

Glacier map and mastodon image are from old ONDR folders.

Alum Creek photo from Polly Horn files.
 

See the Biggest Rock

               

. . . . And Now You Know

 
Goto General W. S. Rosecrans Statue Boulder on Sunbury Square
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(1-21-2016)