Increasing demand for supplies of ground water in the Piedmont of Georgia has necessarily focused attention on granitic rocks, which have a considerable areal extent in this part of the state. These rocks have the property generally known as sheet structure. Major parting planes resulting from sheeting are usually sub-parallel to the rock surface on hills and in valleys and consequently control the circulation of subsurface water. Imperfect shallow pseudosynclinal basins formed by sheet planes in valleys are the receptacles for much subsurface water that percolates along these planes from nearby upland slopes. Therefore, wells drilled in lowlands in sheeted terranes almost invariably produce greater quantities of water than those on the uplands.