millennium BC and that it was an extension of indigenous developments and
not a mere transfer of a cultural pattern by migrants from Mesopotamia, Iran
or Central Asia.
     The rise of indigenous crafts obviously led to an increase in long-distance
trade with western and Central Asia, but this trade did not have the unilateral
effect of cultural borrowing as an earlier generation of scholars had thought.
Those scholars did so, for they were naturally puzzled by the discovery of a
mature civilisation which did not seem to have any local antecedents.
     At present, though we do have a much clearer idea of the indigenous
roots of the Indus civilisation, unfortunately not much is known to us about
the rise of the specific Mature Harappan culture. The exact date of its rise, is
still a matter of debate. Moreover. Mohenjodaro, the most important site, is
badly affected by ground water which covers the earliest strata. The original
foundations of Mohenjodaro are now approximately 24 feet below the ground
water level. The rising of the ground water level was probably one of the
reasons for the decline of that city and it also makes it impossible to unravel
the secrets of its birth. That is why, it is necessary to excavate parallel strata
in other sites of the Indus civilisation which are more accessible and whose
age can be found out by means of radiocarbon dating.
MATURE PHASE
Chronology
The first estimate of the duration of the occupation at Mohenjodaro was made
by Sir John Marshall in 1931. His estimate, based upon general concordances
with Mesopotamia, was from 3250 to 2750 BC. In the following years C J
Gadd published a paper listing a number of Indus, or Indus-like, seals
discovered at Mesopotamian sites, particularly Ur. He also discussed their
ages.
     Majority of seals found might be expected to indicate active trade
contracts between 2350 and 1770 BC. Since then Piggot (1950) and Wheeler
(1946, 1960, etc.) have reviewed the evidence, including cross-dates and
other categories of objects apparently    imported into Mesopotamia.