Excavations at Pine Island, west of Florida, United States of America, revealed numerous thousand-year-old artefacts connected with the Calusa Indians, who disappeared by the 1700s.
Among the numerous artefacts are piece of rope, net and twine, wood pieces, sections of cording and shell tools, white clam shells with a holes knocked in them, threaded with knotted twine. The shells were used as weight on the nets used by the Indians. Archaeologists also discovered pieces of wood on which you can still see the working marks, and seeds of plants such as squash.
The Calusa people developed a complex society that exerted control over much of the Florida peninsula. They built thatched huts, dug canals and crafted tools, utensils and art from bones, shells, clay and wood. Many organic artefacts dug up at the site were preserved due to the anaerobic conditions in which they were sealed by salt water and mud. The artefacts were left, or dropped or lost, at a time when sea level was relatively low but afterwards the water level rose very quickly sealing the deposits in conditions that allowed for preservation.
(after Amanda Inscore & The News-Press)