A defense in depth approach is wisely being utilized in evaluation of several sites for the disposal of high level radioactive wastes, and we hope the same approach will be used in selection of new sites for land disposal of the most toxic of non-radiogenic wastes. The results of laboratory and short term field experiments on the multiple barriers at each site will be used, via interdisciplinary mega-modeles, to predict the fate for buried wastes for periods of millennia and longer. Such analyses are justifiable and challenging, but their results must be used with extreme caution in view of the limitations in geologic prediction of even far simpler systems. The Paleolithic and Neolithic record, of man's global use of the unsaturated zone for preservation of a large variety of objects, has the potential of providing an invaluable analog of the likely fate of solidified toxic wastes buried in similar and semi-arid environments. Though the archaeological record is likely to be qualitative -- and its transference to waste disposal subject to the limitation of arguments by analogy -- it provides a real data set upon which to formulate and independent appraisal of the general ability (barring future human intrusion) of thick unsaturated zones of arid regions to isolate solidified toxic wastes from the hydrosphere for millennia and beyond. Archaeological science can also make substantial contributions to the relate important matters of preventing future human intrusion into toxic waste burial sites, as well as toward the choice of superior solids into which toxic wastes can be incorporated or encapsulated.