Smithsonian Report, 1938. — Vaillant 



Plate 1 



Types of stratigraphical Excavation in the Valley of Mexico. 



Top: Left: Deep pit at El Arbolillo, Federal District, Mexico. The earliest discovered figurine types from the 

 Valley of Mexico were discovered at the base of this trench. Right: Cleaning out a canal in the Nonoalco 

 District of Mexico City. This shallow ditch was filled with vessels discarded in the cyclical destruction 

 of 1507. 



Middle: Excavation in the Nonoalco District. 



Bottom: Left: Peeling layers of refuse at Zacatenco, D. F. This was the source of the first stratigraphical 

 series defined by the American Museum of Natural History. Right: Dissecting an Aztec residential struc- 

 ture at Chiconauhtla, State of Mexico. 



