Although identifying unequivocally the cause of transgressions and regressions from the rock record can be difficult, we can place limits on the possible combinations of sediment supply, subsidence, and sea level that could generate an observed Stratigraphic sequence. Using simple geometric models that estimate maximum rates of change in the three controlling variables, and combining these with other limits derived from field observations, we can plot a solution set to define the most likely range of variations in these three primary controls on shoreline migration. This approach shows the amount each controlling factor must change alone, or in concert, to account for the stratigraphy. These quantitative values can be used to decide what is geologically reasonable and what is not. Although a unique solution may not be available, we can calculate the required parameters for the observed shoreline migrations, which provide a basis for informed interpretations.