Shell works

Shell works include mounds and other deposits, with features described as borrow pits, canals, causeways, cisterns, crescents, sunken plazas, ponds, ramps, raised platforms, ridges, rings, walls, and "water courts".

The largest shell works were constructed during the Woodland period in southwest Florida, from Charlotte Harbor to the Ten Thousand Islands, including Estero Bay.

Cushing also noted that Mound Key covered 128 acres (52 ha), and Chokoloskee Island was over .5 miles (0.80 km) in diameter, and up to 27 feet (8.2 m) high.

[6] The Mark Pardo Shellworks Site in Cayo Costa State Park near Bokeelia was added to the National Register of Historic Places in 1996.

European accounts of encounters with the inhabitants of southwest Florida in the 16th and 17th centuries describe houses on top of mounds, and ceremonial use of different parts of shell works sites.