the "Mississippianised" cultures adjacent to the main areal of the mound building cultures. This culture was also mostly extinct in the 17th century, but remnants may have survived into the first half of the 18th century. While this culture shows strong Mississippian influences, its bearers were most likely ethno-linguistically distinct from the Mississippians, possibly belonging to the Siouan phylum. The only tribal name associated with the Fort Ancient culture in the historical record are the Mosopelea, recorded by Jean-Baptiste-Louis Franquelin in 1684 as inhabiting eight villages north of the Ohio River. The Mosopelea are most likely identical to the Ofo (Oufé, Offogoula) recorded in the same area in the 18th century. The Ofo language was formerly classified as Muskogean but is now recognized as an eccentric member of the Western Siouan phylum. The late survival of the Fort Ancient culture is suggested by the remarkable amount of European-made goods in the archaeological record. Such artifacts would have been acquired by trade even before direct European contact. These artifacts include brass and steel items, glassware, and melted down or broken goods reforged into new items. The Fort Ancient peoples are known to have been severely affected by disease in the 17th century (Beaver Wars period). Carbon dating seems to indicate that they were wiped out by successive waves of disease. Massacre and revolt Because of the disappearance of the cultures by the end of the 17th century, the identification of the bearers of these cultures was an open question in 19th-century ethnography. Modern stratigraphic dating has established that the "Mound builders" have spanned the extended period of more than five millennia, so that any ethno-linguistic continuity is unlikely. The spread of the Mississippian culture from the late 1st millennium CE most likely involved cultural assimilation, in archaeological terminology called "Mississippianised" cultures. 19th-century ethnography assumed that the Mound-builders were an ancient prehistoric race with no direct connection to the Southeastern Woodland peoples of the historical period who were encountered by Europeans. A reference to this idea appears in the poem "The Prairies" (1832) by William Cullen Bryant. The cultural stage of the Southeastern Woodland natives encountered in the 18th and 19th centuries by British colonists was deemed incompatible with the comparatively advanced stone, metal, and clay artifacts of the archaeological record. The age of the earthworks was also partly over-estimated. Caleb Atwater's misunderstanding of stratigraphy caused him to significantly overestimate the age