Probability That a Fossil Absent from a Sample Is Also Absent from the Paleolandscape

p s t m w t n p a g e r t A procedure to calculate probability limits for the inference that the absence of a taxon from a woodrat (Neotoma) midden implies bsence from the paleolandscape uses paired samples of modern egetation communities and paired samples of paleocommunities. ssumptions are: (1) each member of a sample pair is an indeendent measure of the same vegetation assemblage; (2) behavoral patterns of woodrats are the same as each midden in a paired ample is constructed; and (3) the probability of fossilization is ero when a taxon is absent from the vegetation. The procedure rovides a logical test of data consistency: the upper probability imit of making a false inference should be greater than the lower imit. Averaged over 140 plant taxa, the upper and lower probaility limits for a false inference were 11 and 7%, respectively. ore than 70% of taxa passed the logical test, indicating a reliable rocedure. For many taxa that failed the logical test, four potential xplanations account for this failure, two of which can be solved by imply increasing sample sizes. Using analogous assumptions, the rocedures are applicable to other types of stratigraphic sampling uch as macrofossils from sediment cores or fossils from biostratiraphic units. © 2000 University of Washington.