Archaeological reports of silica froth are noted from Kansas to Texas, and are usually interpreted as evidence of burned grass- or cane-thatched buildings. However, many archaeological excavations in the Caddoan region fail to mention this material. Does this reflect idiosyncratic factors in the formation of silica froth, lack of expertise on the part of excavators/analysts, or differential recovery techniques? Archaeological and experimental data indicate that Caddoan houses frequently left silica froth as a residue when they burned. The implications are that archaeologists may be missing this key architectural item and that silica froth may be used to infer the presence of a house in the absence of traditional features such as post molds
