 Four years later, he became a full professor.Between 1940 and 1946, Griffin spent nearly three field seasons working on surface surveys, while his partner Phillips worked on stratigraphic excavations at sites in the southeast, work published in 1951 in a monograph that has come to be regarded as a classic in American Archaeology, Archeological Survey In the Lower Mississippi Alluvial Valley, 1940-1947 (Phillips, Ford and Griffin 1951) After this project, Griffin began work with A. C. Spaulding on the Central Mississippi Survey in 1950.Fieldwork was done in southeast Missouri and at the Roots site near the Kaskaskia River, but the main project was at Cahokia.