By Bill Witherspoon
“That boulder has a bad attitude.”
I was leading a geology walk into Zahnd Natural Area on Lookout Mountain, and I had inserted an awful pun. “Attitude” can refer to the orientation of rock layers in space. Most of the rock layers atop flat-topped Lookout Mountain have a near-horizontal attitude. This is how the layers settled on a delta plain about 300 million years ago. They were too far from the impact of Africa into North America to be much disturbed by fault movements that tilted rock layers in the Valley and Ridge, not far to the east. The layers in this particular house-sized block, however, were badly askew at an angle of about 45 degrees. I explained that the soft shale that this sandstone rests on has a tendency to flow downslope at a rate too slow to see. Nearby trees, their trunks curved gracefully because the ground slowly tilted them as they tried to grow vertically, confirmed the point.
There are so many ways to socialize in the outdoors. The first Sierra Club outing in which I participated actually turned out to be my first camping date with my now wife of 34 years. She wowed me by creating fondue on a one-burner backpacking stove. Nowadays, I enjoy helping others appreciate features in the landscape that they might have overlooked, like a boulder with a bad attitude. The best part of my dream job from which I retired in 2014 (teaching for 17 years at Fernbank Science Center of the DeKalb County Schools) was leading hundreds of climbs with elementary school kids up Stone Mountain and Arabia Mountain.
Getting to lead dozens of adult and family geology hikes since then is a happy consequence of the 2013 publication of Roadside Geology of Georgia, of which I am a co-author with Pamela Gore. The book is the 33rd in a series that has been explaining the geologic stories behind America’s scenery to more than a million readers since 1972. Besides geology walks, I have been able to present slide shows that connect Georgia geology to topics including Dahlonega’s gold rush, the Civil War, the “river rivalries” that shaped mountain scenery, and most recently, Georgia’s climate history.
On April 5, I will join the Centennial Group for their monthly meeting. The last time I joined Centennial, I led a walk and presented “Gorges Atlanta.” This time, I will talk at the meeting about “Georgia’s Climate: Past, Present, and Future.” As on the last visit, you can join me at 6:00 PM for a short geology walk along Rottenwood Creek, in Life University’s park-like historic building area, down the hill from Centennial’s meeting location.
While I did not have a weekend date available for April’s outings month, I have offered to lead Sierrans on Pigeon Mountain in northwest Georgia, date TBD, to visit 100-year-old iron mining tunnels and a waterfall that has built its own apron of calcium carbonate. Watch the outings listings later this spring and summer for that opportunity.