"It may perhaps be important to make a statement regarding what I mean by the term ‘Late Harappan’, since it has often been used rather loosely or in different senses by different scholars. To me Late Harappan would mean a culture-complex which has tranformed itself from the Mature Harappan, losing some of the latter’s traits and evolving some new ones, but still identifiable as having been derived from the latter."
January 1, 1970
https://en.wikiquote.org/wiki/Periodisation_of_the_Indus_Valley_Civilisation