A comprehensive Flood model requires an appraisal of the rock record. At the global scale, knowing the global volume and distribution of such rock is an important first step. This requires significant mapping and quantifying of rock volume, which in turn requires determining basal and upper diluvial boundaries for each location. An important question in determining basal boundaries is how to address Precambrian sedimentary and volcanic rocks. We present strategies for evaluating such rocks vis a vis the Genesis Flood, concluding that many such rocks should be considered diluvial.