Figure 1.3: For a given set of well data (clays and gravel borings), a geologist might interpret the subsurface, and how a resultant simulation of contaminant migration might appear. For the given data, this description may be reasonable, but it is only one possibility, and may be incorrect. The description and results would only be correct by chance, and the results are not associated with a quantified level of uncertainty for the predicted distribution or magnitudes of concentrations.