This graphical technique utilizes only three types of artifacts from the collection to the seriated. The relationship between the three selected types is plotted on three-pole graph paper. The points on the graph are clustered along a line representing change through time; hence the archaeological materials are arranged in their correct temporal sequence. Data from Paragonah, Utah, and Pindi, New Mexico, two Southwestern sites for which the time sequence is known, are used for empirical tests of the seriational technique. In both cases there is close agreement between the results of the seriation and the time sequence revealed by field evidence. SERIATION, or the arrangement of archaeological materials in their chronological order by overlapping of similar traits in different finds, has a long history dating back to the "Sequence Dates" of Petrie (1904). In recent years, increased attention has been given to problems of seriation; two notable advances include the graphical technique developed by Ford (Ford and Willey 1949); and the statistical method proposed by Brainerd (1951) and Robinson (1951). Despite certain shortcomings, both of these methods work and both of them provide more sensitive measures of chronological difference than anything we have had heretofore. Some criticisims of the methods have been raised (Lehmer 1951; Bennyhoff 1951) and it is apparent that seriation techniques are neither a substitute for good field techniques nor for an adequate typology (Dixon 1956). Still, I am convinced from my own application of both of these methods to the field data from excavations, that the following statements are valid: 1. Both the Ford and the Brainerd-Robinson methods yield results that are consistent with the field data. In many cases the methods can be checked against stratigraphy, building superposition, and other field observations (Belous 1953; Collier 1955). If the results are not consistent with the field observations, other methods of age determination must be applied (Dixon 1956). *Presented at the 57th Annual Meeting of the American Anthropological Association, November 23, 1958, Washington, D.C. 2. Seriation methods provide a more detailed picture of temporal change than stratigraphy and field observations alone. Application of these methods can give a more objective determination of the number of cultural periods present, can indicate interruptions in the temporal sequence, and can sometimes indicate the presence of mixed or disturbed collections in the sequence. Application of seriation techniques is not mere data-juggling, but an extremely useful adjunct to ordinary methods of analysis. DESCRIPTION OF THE METHOD In beginning a seriation, the first step is selection of the trait to be seriated. This trait must have the following characteristics: (1) abundance; (2) measurable diversity (more than one type); (3) long time span in terms of the sample seriated (the feature should occur throughout the time span studied). If pottery is present this is likely to be the best feature for seriation, although this is not always true. In southern California it is seldom possible to seriate pottery collections on a statistical basis because there is not enough diversity of types. Assuming that pottery is used for the seriation, the next step is to reduce the number of pottery types to three for purposes of the analysis. The reduction to three types may be done in several ways: 1. Selecting the three most abundant types will usually work. In this case all other types are omitted from the seriation, although they may sometimes be used as a check on the results as described below. 2. In cases where a large part of the pottery sample consists of a common type (such as a plainware), occurring in about the same proportion throughout the time span of the sample, the common type may be skipped and the seriation done with the next three most common