I am sure you have seen them as you drive the roadways of Fairfield County. Sometimes they are in front yards, along road ditches, innocently poised next to a pond, or you might even see a large number of them accumulating on the side of a field.
Do you know what I speak of?
Yes, those boulders that are used in landscaping, as driveway markers, or as rock piles accumulating as farmers remove them from their fields. These non-native boulders are intriguing indicators of past glacial activity. In geology they are referred to as glacial erratics, rock fragments carried some distance from its source by a glacier usually deposited on materials of a different composition.
Erratics were fragmented from their source bedrock in Canada, hundreds of miles away, and transported in a massive glacier (or glaciers) to places like our front yards, farm fields, and even to the top of a hill. Erratics can be colorful, can be composed of feldspar and quartz, and can appear quite different form the sandstone bedrock found in Mount Pleasant or in the cliffs around the Hocking River by Rock Mill Park. Many of the erratics found around homes or ponds were likely uncovered during the excavation of a foundation or pond and were simply incorporated into the landscape to spare the effort and cost of removal.
So, whenever you’re out riding around in Fairfield County and you see a boulder just hanging out along the road, in a fence row, or in someone’s yard consider that it, too, is just out for a jaunt far from home waiting for that next massive glacier to move it a little further down the line.
–Dan Mole, Program and Volunteer Specialist
Discover Fairfield County’s glacial history with our guided program, Glacial Features of Fairfield County, Saturday, March 14.