Six large-amplitude ridges, about 35 km in length and 300-1,000 m in width, parallel the mainland of Gulf County, Florida. Associated troughs are from 0.5 to 2.0 m above sea level and have a maximum width of 200 m. The intercoastal waterway cuts the ridges exposing low-angle parallel beds dipping primarily south-southwest at less than 5°. The ridges differ in thickness and each displays 3 distinct zones of laminae. Virtually all bedding appears to be of beach origin, mostly of foreshore type but with some backshore features. Eolian and current bedding is absent.

Study indicates that systematic changes occur between the 3 zones of the ridges. Average-mean grain size and standard deviation decrease upward as skewness and kurtosis increase, a trend observed in profiles taken up the beach face of some Florida panhandle beaches. The ridges are composed mostly of white-quartz sand with humate lenses of decayed organic matter. Bedding and sediment parameters suggest that the ridges are ancient beach deposits, which locally coalesce to form larger ridges. A large cuspate foreland of Holocene age, the St. Joseph Spit, protects the ridges from wave action, thus suggesting a probable minimum Sangamon age for the ridges.

End_of_Article - Last_Page 1839------------