Abstract
The differential longevity of ceramic vessel forms affects the frequencies of these forms in an archaeological midden. The observed frequencies of modern Conibo vessel forms in use are projected into the archaeological record and the results are compared to the frequencies of antecedent forms from archaeological sites on the Upper Ucayali. Some of the variables, other than differential longevity, needed to account for the differing frequencies are discussed. The utility of longevity data for estimating the population needed to produce an archaeological midden is also explored.