Although Dr. Dorothy Hosler serves as Principal Investigator, this project is designed and will be conducted by Dr. Nicola Strazicich. The goal is to study the manufacture of a prehistoric type of pottery termed `pseudo-cloisonne.` At the onset of the Mesoamerican Classic period, around 200 A.D., artisans in North and West Mexico began to make this highly unusual ceramic decorated with intricate inlay designs. What makes the situation unusual is that this single distinctive type of pottery was used by four socially, politically and geographically distinct cultures over a 700 year period. Normally pottery types of such complexity are culture specific and, in fact, are often used by archaeologists to define such desecrate entities. Although not unique, the pseudo-cloissonne case contravenes a generally accepted archaeological rule and thus is of specific interest. Dr. Strazicich discovered that the four areas are geologically distinct and it is highly probable that the clay sources are different from region to region. This means it is, in principle, possible to chemically characterize the clays in each and then match trace element signatures in the archaeological ceramics to source areas. One can thus gain insight into the interaction between regions and determine whether the ceramics were locally produced, which indicates sharing of detailed technical knowledge, or whether all were manufactured in one area and then distributed through trade networks. Dr. Strazicich will collect and analyze a total of 110 clay samples as well as 270 vessels from securely excavated contexts. She will employ petrographic analysis of pottery and clays to identify geological source materials and regional clay preparation techniques. Neutron activation analysis of vessels and clays will provide trace element data and electron microprobe analysis will be employed to determine chemical compositions and plastic constituents in the cloisonne decoration. Scanning Electron Microscopy will be used to characterize ceramic microstructure. The research is important for several reasons. It will not only shed new light on the development of social complexity in Mesoamerica but also provide insight into social and economic interactions which may have occurred in many areas of the world among prehistoric cultures at a similar level of social complexity.