"The Pre-Harappan and the Harappa cultures are not two disparate entities but urban and rural aspects of the same cultural phenomenon. The Harappan phase at Kot Diji, Amri and Kalibangan, should not be understood as one culture supplanting another, but like a city corporation taking over a sub-urban village to urbanise."
January 1, 1970
https://en.wikiquote.org/wiki/Periodisation_of_the_Indus_Valley_Civilisation