sites display contact with Harappan civilisation, but only a few are fully developed Harappan ones. As of 1977, about 90% of the Indus script seals and inscribed objects discovered were found at sites in Pakistan along the Indus river, while other sites accounts only for the remaining 10%. By 2002, over 1,000 Mature Harappan cities and settlements had been reported, of which just under a hundred had been excavated, mainly in the general region of the Indus and Ghaggar-Hakra rivers and their tributaries; however, there are only five major urban sites: Harappa, Mohenjo-daro, Dholavira, Ganeriwala and Rakhigarhi. As of 2008, about 616 sites have been reported in India, whereas 406 sites have been reported in Pakistan. Unlike India, in which after 1947, the ASI attempted to "Indianise" archaeological work in keeping with the new nation's goals of national unity and historical continuity, in Pakistan the national imperative was the promotion of Islamic heritage, and consequently archaeological work on early sites was left to foreign archaeologists. After the partition, Mortimer Wheeler, the Director of ASI from 1944, oversaw the establishment of archaeological institutions in Pakistan, later joining a UNESCO effort tasked to conserve the site at Mohenjo-daro. Other international efforts at Mohenjo-daro and Harappa have included the German Aachen Research Project Mohenjo-daro, the Italian Mission to Mohenjo-daro, and the US Harappa Archaeological Research Project (HARP) founded by George F. Dales. Following a chance flash flood which exposed a portion of an archaeological site at the foot of the Bolan Pass in Balochistan, excavations were carried out in Mehrgarh by French archaeologist Jean-François Jarrige and his team in the early 1970s. Chronology The cities of the ancient Indus had "social hierarchies, their writing system, their large planned cities and their long-distance trade [which] mark them to archaeologists as a full-fledged 'civilisation.'" The mature phase of the Harappan civilisation lasted from c. 2600–1900 BCE. With the inclusion of the predecessor and successor cultures – Early Harappan and Late Harappan, respectively – the entire Indus Valley Civilisation may be taken to have lasted from the 33rd to the 14th centuries BCE. It is part of the Indus Valley Tradition, which also includes the pre-Harappan occupation of Mehrgarh, the earliest farming site of the Indus Valley. Several periodisations are employed for the IVC. The most commonly used classifies the Indus Valley Civilisation into Early, Mature and Late Harappan Phase. An alternative approach by Shaffer divides