Large accumulations of shells can be found in flat coastal regions and along the lower course of big rivers all over the world. Many of these shellmounds have been investigated by archaeologists and have been found to contain, besides shells, considerable quantities of ash, numerous artifacts of stone and bone, occasionally potsherds, and often a relatively large number of human skeletons. Their contents and stratification reveal these mounds to be deposits of kitchen refuse, accumulated on prehistoric dwellings sites by tribes whose main source of food was fish and mollusks.

In Brazil such shellmounds can be found not only all along the Atlantic coast and up the Amazon, but even in Mato Grosso, along the banks of the Paraguay River. No systematic survey of Brazilian shellmounds has yet been made.