Geologist Tammy Braden, a freelance geologist, confirmed that we are sitting on top of a fantastic limestone shelf that was laid down about 450 million years ago when our particular tectonic plate was sitting near the equator. The shallow sea teemed with trillions of shelled creatures and when they died their shells built up a thick layer of limestone sediment. Then a mere 12,000 to 15,000 years ago the glaciers dropped in and graciously scrapped off millions of years of accumulated sediment which left our limestone exposed, along with the fossil remains of those sea creatures. In addition to luring fossil hunters, this limestone layer also protects our drinking water by filtering impurities out of the surface water that seeps into the Miami Valley aquifer.
Braden pointed out, however, that unlike fishing a complete novice can hunt and find fossils along many of our rivers.
“All the equipment one needs is a hammer and perhaps a magnifying glass,” she said.
The best sites are along the Stillwater River below Englewood Dam, below Germantown Dam, and the spillway at Caesar's Creek Dam. Or, if you can find a friendly limestone quarry owner who will allow you to shift through the quarry's slag, you may hit the fossil jackpot. The largest complete trilobite* fossil ever found was accidentally uncovered during the construction of Huffman Dam in 1915. You can see it at the Smithsonian Museum. Don't be greedy; however, a fossil hunter is allowed to remove only a few fossils from a site per visit. Of course, you can "catch and release" as many fossils as you wish. (For more information on our fossil treasure trove go to the website: http://issuu.com/metroparks/docs/metroparks_fossil_brochure).
If you are hesitant about searching through rocks on a river bank you can actually spot fossils in downtown Dayton by examining some of the limestone blocks that were used to construct buildings like the old courthouse. Forget how you might look to a passerby who sees you staring at what appears to be a blank wall.
I am fond of fossils, but as a teacher it was Braden’s journey to becoming a geologist that really resonated with me. It illustrates how an encouraging word from a teacher can sometimes alter the trajectory of a student’s life. In high school Braden admitted to being a so-so student drifting through her courses. Then, her Earth science teacher at Miamisburg High School, Joseph Beringer, told her, “You are really good at this.” Suddenly, Braden knew that she wanted to be a geologist and nothing was going to deter her from entering even such a male-dominated profession, including a Miami University professor who told her, “Women can’t be geologists.”
Braden certainly proved him wrong. She also has not forgotten who provided that first spark which ignited her ambition. Braden returns to Miamisburg High every year to be a guest lecturer in Beringer’s Earth science class.
*Imagine a roly-poly bug the size of a Thanksgiving dinner serving platter.
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