The finger
A dozen finger ridges, to wide and to m long, radiate out from the arc of mounds towards the water. The finger ridges are separated from each other by canals. Several of the finger ridges are associated with "water courts", depressions deep enough to retain water. Some may have stored rain water for drinking, while others, with a connection to open water, may have served as fish traps. The finger ridges are also constructed from clean, whole oyster shells, but are covered by a midden layer of black earth and shells with many artifacts and fish bones. Shell samples from the lower levels of the finger ridges yielded calibrated radiocarbon dates of 660 to 810, while samples from below the midden layer yielded dates of 990 to 1290. Some of the ceramics found in the midden layer are attributed the Glades IIIa period, 1200 to 1400. There is no evidence of occupation of Dismal Key after that period (until the 20th century).