Relatives of this clam are still extant today and are an important economic resource in coastal areas. The name "Mercenaria" comes from the fact that the modern shells, with their bright purple colors, were used as wampum by pre-colonial Indians and money during early colonial times. These clams burrow shallowly into mud and feed through a siphon that extends above the sea bottom. Mercenaria shells can reach very large sizes. Other species of this genus can be found in the Yorktown and other formations of the Coastal Plain, such as Mercenaria mercenaria (the modern representative of this genus) in the Tabb Formation, and Mercenaria tridacnoides in the Upper Yorktown Formation.