The clays of the industrially important kaolin district in central Georgia contain measurable pyrite, an iron sulfide mineral that can provide a window into the early diagenetic history of the deposits. Measuring 34S of this pyrite yields fractionations caused by bacterial influence ranging from 6.4 48.9. These fractionation values demonstrate depositional environments ranging from open sulfate supplies (high fractionation) to closed sulfate supplies (low fractionation) indicating four different depositional regimes within the Huber Formation and Twiggs Clay of central Georgia: 1. The lower Huber Dissimilatory Sulfate Reducing Bacteria (SRB) dominated Open System (~363 375 feet) 2. The upper Huber Disproportionate SRB dominated Open System (375 401 feet) 3. The Top of the Huber Closed System (~400 404 feet) 4. The Twiggs Dissimilatory SRB dominated Open System (401 409 feet). This data, in conjunction with powder X-Ray diffraction data, shows that these clays have undergone two periods of post depositional oxidation.