“"The term 'Early Harappan' as opposed to 'Pre-Harappan' has gained acceptance for a number of reasons. The principal reason is the evidence for cultural and historical continuity between the Early and Mature Harappan as well as the premise that the process of change was primarily autochthonous. It involved the peoples of the Greater Indus Valley itself, without significant or out-of-the-ordinary, external influence . . ."”