Using maps and cross-sections of the cultural deposits from HARP, surfaces were generated to represent the interfaces of cultural layers in the mounds at Harappa. This represents the growth of the city of ancient Harappa vertically and through time. The stratigraphy at Harappa is based on ethnostratigraphic principles, with the layers being defined by artifacts and architectural style. The stratigraphic layers are the cultural remains of ancient Harappa. Each ethnostratigraphic unit has been assigned a chronological time fame based on the radiocarbon dating described previously. The city literally is built upon the foundations of its ancestors.

Period 1 deposits represent a pre-urban phase of development and exist beneath the northwest corner of Mound E.