Figure 6-2. Upper Devonian-Mississippian stratigraphic relations of western New York state (Lake Erie District) and northwest and north-central Pennsylvania. Stratigraphic columns, including thicknesses, are modified from Lindberg (1985). Devonian time scale (including the Devonian-Mississippian boundary) is from Kaufmann (2006); Mississippian time scale is from Gradstein et al. (2004). Note the marked increase in sedimentation rate halfway through the Famennian stage, perhaps glacio-eustatic in origin (e.g., Veevers et al., 1987); that may have been responsible for the onset of disequilibrium in the Upper Devonian Rhinestreet shale.