A long time ago in Germany, my first geology teacher taught us a trick for figuring out the local bedrock in an area. “Look at the church,” he said. “It’s likely to be built with what’s available in the nearby quarries.” A field trip examining the sandstone and limestone church buildings of rural South Germany confirmed his idea. In Georgia, wood dominates as a construction material, but one can still get a good idea of the underground geology.
Elberton stands out as a source of beautiful granite. With its richly textured bedrock of grey, black and white minerals, Elbert County has supplied the stone for countless monuments and grave markers. The famous Georgia Guidestones on Rt. 77 are made of Elberton granite. In town, the foundation of New Era Baptist Church on Mill Street is built of granite as well, along with the marker stone at its entrance.
Granite from Stone Mountain forms the foundation of Georgia’s State Capitol in Atlanta. The Stone Mountain granite is a close cousin of the Elberton variety. Both formed under enormous pressure deep underground when liquid magma, trying to work its way up to the surface, got stuck and cooled.
In some places the local bedrock was once limestone, deposited at the bottom of an ancient ocean. Pressure from the movement of the continents compressed it into marble. Some of the most beautiful marble comes from Pickens County. United Methodist Church in Tate, although a beautiful building with its many dormers and shaded patio, doesn’t show the local bedrock. But nearby Tate Elementary School is stunning with the thousands of marble blocks that form its walls.
In the USA, my teacher’s “church test” doesn’t work as well as it does in Europe. However, the red walls of many North Georgia church buildings offer another clue. Countless millennia of rainwater and chemical decay have broken down the top layers of the ground into clay minerals. While clay tends to give farmers and gardeners a tough time, it’s an excellent material for making bricks. Mix clay with water, put the resulting mud into a form, fire it in a kiln, and you have a brick. The area between Atlanta, Athens and Gainesville is home to at least two dozen brick companies. Thousands of red building exteriors leave no doubt about one of North Georgia’s best geologic resources.
Rudi Kiefer, Ph.D., is a professor at Brenau University, teaching physical and health sciences on Brenau’s Georgia campuses and in China. His column appears Sundays and at gainesvilletimes.com.