|MadSci Network: Earth Sciences|
In answer to your question, it is impossible to make a definite judgment about your material without seeing it. If you could send a digital photograph of a good example I might be able to identify it. Two things that I can say, however, are: (1) It is not uncommon for geological processes such as weathering and erosion to fashion rocks into shapes that resemble bones or other organic remains. Most museums are familiar with such items brought in for identification. For example, I have seen the conchoidal fracture on a piece of broken flint (resembling a fracture on a piece of a broken glass bottle) mistaken for a fossil bird footprint because it happened to produce a three-pronged shape. A fossil collector whom I know once misidentified a piece of rolled mudrock which fell out of the centre of a suspicious concretion as an ichthyosaur flipper bone! It did look rather like a bone! (2) The rocks of North Georgia are broadly of two classes, neither of which would contain vertebrate fossils. One type is crystalline metamorphic rocks such as schist, which is formed about 30 km deep in the Earth’s crust by high pressure and temperature, and could never be host to a fossil of any kind. The other type is sedimentary rocks of marine origin from the Palaeozoic Era, such as shales and limestones, which contain fossils such as trilobites, but which are too old to contain the remains of large vertebrates, and certainly not land-living vertebrates. Still, there is always a possibility that you have something. Relatively young sediments ranging from a few tens of thousands to, say, a couple of million years old, occur as what geologists call superficial deposits on the surface in many areas where the underlying geology is much older. Such sediments are often poorly consolidated clays and sands, as they have not had time to become hard rock. Here in Berkshire, in England, there is a Pleistocene age river gravel quarried for aggregate that sometimes yields elephant teeth – I know, because I was present when one of my students found one on a field trip to a local quarry! Such sediments do often yield fossil bones of mammals and other vertebrates. So, if you want to email a photograph I’ll be glad to have a look! Kind regards, David Scarboro
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