The coastal cell concept introduced by Stapor (1971) is used for estimating mass sediment budgets along coastlines. May and Tanner (1973) later identified five key points (a,b,c,d,e) and called this concept the "a-b-c. .." model. For an "ideal" cell model, one with simple headland and bay configuration, PL (littoral component of wave power) and q (quantity of sand transported past any given point) approximate a simple sine curve, as is easy to visualize, but in nature many factors operate so that a simple sine curve cannot be applied in most cases. The map outline of the beach, whether it is generally convex or concave seaward, influences the model in such a way as to skew it toward either point "a" or "e." This is not to say that the ideal model does not apply to any coastline whatever, but that the chances are much greater for departures from the "ideal" model along most natural coastlines. Sediment movement data, from a bathymetric comparison of charts of a natural convex-seaward coastline, have been computed for Dog Island, Florida. The PL curve, as well as curves for q and dq/dx, show a pronounced skewness toward the "e" point. By observing the WAVENRG computer program (May, 1974) plots for the PL curve along Cape San Blas, Florida, and the eroding and depositional distances along the natural convex- seaward coastline of Dog Island, Florida (where the "a-b-c" segment of the southwest drift cell is roughly five times as long as the "c-d-e" segment), the asymmetry of the curves is easily visible. A granulometric and orientational beach ridge study on the northeastern end of Dog Island, Florida, indicates that although local energy conditions have remained similar (low-to-moderate) through the last 3,000 years, wind and wave approach have varied. These varying conditions have resulted in at least two different beach ridge orientations which also indicate changing transport directions (longshore, offshore-onshore). Superimposed on these wind and therefore wave approach directions are sea level fluctuations, plus and minus 1 to 2 met5ers from present. In the Dog Island area from 1872 through 1935 sea level has risen on an average of 3 mm/year to result in an average shoreline retreat of 2m/year excluding erosion or deposition.