While the Lenape tradition keepers perished in the conquest, the archaeological facts support Rafinesque's account and the Red Record as reliable.
For a discussion of the appearance in eastern Wisconsin of Oneota culture, see Victoria Durst, The People of the Dunes, Whitefish Dunes State Park, 1993, p. 46-63. For a discussion of the appearance of Oneota culture at Redwing, see Clark A. Dobbs, Red Wing Archaeological Preserve, Goodhue-Pierce Archaeological Society Planning Committee, Institute for Minnesota Archaeology, Minneapolis, 1990, p. 7. For a discussion of the western Oneota culture appearance and distribution, see James L. Theler and Robert F. Boszhardt, Twelve Millenia, Archaeology of the Upper Mississippi River Valley, pages 152-155, particularly abandonment of effigy mounds, p. 155. In their book on The Gottschall Rockshelter, Robert J. Salzer and Grace Rajnovich cite cannibalism at Aztalan, citing Fred A, Finney and James B. Stohlman, The Fred Edwards Site, New Perspectives on Cahokia, Prehistory Press, Madison. One problem assigning this here to a climate collapse is Oneota occupancy at Aztalan, following on the Stirling phase occupancy at the site. For carbon dates at this site: Lynne Goldstine, Joan Freeman, Aztalan State Park, Wisconsin Department of Natural Resources, 1995 for group burials and stockade history.
For radio carbon dates for the stockade and later fall of Cahokia, see the literature. For the radio carbon dates for Angel Mounds, see the literature. For "Middle Fort Ancient" sites in this area, see the literature - but note that "Middle Fort Ancient" attacker and defender sites are seldom clearly delineated. In this regard note especially the Ana Lynn site on the Blue River in Indiana, rc 1170-1270 CE, for evidence of the Lenape flanking move around Cahokia ("Twakanhah" in Iroquois, "Towako" in the Walum Olum) and their recent defeat of a Mississippian people on the Ohio River.
For the east central areas of North America, the "Wellsburg" complex appears to be equivalent to Oneota. It goes by a yet another different name further east in far Western Maryland and central Pennsylvania, a name which escapes me entirely since my stroke.
In as much as Rafinesque had no knowledge of any of these excavations when he purportedly concocted his "forgery", that it is a forgery is highly unlikely, as the tradition agrees in detail with the physical evidence of the Lenape migration in North America during the Little Ice Age. Thus in my opinion one must side with Brinton's appraisal of Rafinesque's work.
You may be involved with Lenape who think otherwise; which in my view is unfortunate, because at the end of this line of the physical evidence of the Lenape migrations lie the Lenape homelands at the time of European contact. If the preceding chain of physical evidence is denied, then the Lenape have no claim to those lands, as there is no physical evidence for them ever having lived in them. The Lenape will also loose any claim to the remains of their ancestors along the way.