Go just a short distance from your place to the Oglesby Pond area and dig. Many a deep well has been started only to have to start another hole because of hitting solid rock. Also most of the flint rock in our area that is found in prehistoric sites along the creeks came from the Ogeechee River, Horse Creek, Beaver Creek and Brier Creek quarry sites. The white quartz rock mentioned is common and can be found in the borrow pits along Lott's creek especially around the Cypress Lake area. Some of those are big as softballs.I live right up the road from OWM, and I've been over 20' deep with an excavator - there ain't no rocks in this neighborhood.