With National Science Foundation support, Dr. Elizabeth Brumfiel will conduct archaeological excavation and exploration in the Xaltocan region of the northern basin of Mexico. Xaltocan was an ancient political center located ca. 35 kilometers north of modern Mexico City. In 1987, Dr. Brumfiel conducted extensive surface survey of the area and that research provides the baseline for the current project. She will excavate ca. 20 2x2 meter test pits, in addition to two deep excavations. Using these data she will pursue several goals. First, since this Northern Basin region is not well known, she will develop a ceramic chronology which will provide a basis for the assignment of individual surface sites. Secondly, she will examine the relationship between surface and subsurface occurrences, and this will allow researchers to determine how well surface materials reflect what lies below in sealed contexts. This research is of interest for several reasons. Many large surface surveys have been conducted in the Basin of Mexico and based on these results, demographic reconstructions attempted. However, it is unclear how valid it is to use surface materials in this way, and Dr. Brumfiel's work will provide the basis for such an assessment. Given rapid urbanization in the Basin and the consequent destruction of archaeological sites, future researchers will have to rely increasingly on surface survey data, and in this context Dr. Brumfiel's research assumes great importance. It is also known from ethnohistorical literature that Xaltocan played a critical role in the late prehispanic Mexico, yet the area has not been studied in an archaeologically systematic fashion. This is just what Dr. Brumfiel proposes to do. The project is also important because it will support research at an undergraduate institution, will directly involve students in the work, and, therefore, hopefully encourage them and their classmates to pursue scientific careers.