The Kingsley Plantation in Jacksonville is a well preserved relic of the era of slavery in America. The estate had 60 to 80 enslaved Africans who worked the plantation. Their cabins, made of tabby, are preserved in whole and in part near the entrance to this National Park. Tabby is a building material made from whole and ground up oyster shells, sand and water and coated with lime putty made from burned and ground oyster shells. Here is a link about tabby, and a view of the buildings.
[url]
http://en.wikipedia.org/wiki/Tabby_%28cement%29[/url]
It was not my original intention to have this photograph serve in a documentary way, but the subject is too interesting not to want to offer more than just the link to tabby, so here's a link to the plantation itself. It is an absolutely fascinating story.
[url]
http://en.wikipedia.org/wiki/Kingsley_Plantation[/url]