Jannie Loubser pointed out to me an interesting comment on cairns. This is found in an article by Richard Edging and Steven R. Ahler titled "Rock-Art and Late Woodland Settlement in the Northern Ozarks," published in The Rock-Art of Eastern North America: Capturing Images and Insight (eds. Carol Diaz-Granados and James R. Duncan), Tuscaloosa (AL), 2004, 90-109.
On page 102-103 is the following under Cairns: "Rock cairns are an essential element in all of the site complexes documented on FLW (), and they are linked directly to Late Woodland mortuary ritual. Rock cairns occur singly or in clusters and are located almost exclusively on bluff crests and ridge spurs overlooking perennial streams (Ahler and Albertson 1996; Niquette 1986:19). Bluff crests were closen because bedrock was either exposed or accessible near the surface (O'Brien and Wood 1998:263), and perhaps their prominent and elevated positions on the landscape held ritual significance as well. Many cairns are located immediately above cave sites.
"In the early 1980s, Niquette excavated portions of 11 cairns across the installation (Niquette 1986; Niquette et.al. 1983). Remains of individuals were usually placed on bedrock, and stones were piled up to form a mound. Later burials may be placed at the periphery of the original mound, creating an accretional mound with multiple construction stages. Diagnostic artifacts found in the cairns include Late Woodland and Maramec series ceramics... While rock cairns have been viewed as functioning as burial places, the recovery of only secondary burials indicates that the cairns are only one portion of a more elaborate mortuary process. This is supportive of Hall's (1997) thesis that secondary or bundle burials represent a long process of mourning that binds the community together through time. Thus cairns were likely focal points for religious and social ceremonies in addition to being mortuary sites."