SOCIAL SCIENTIST was written from left to right. Though iron appeared in the western Ganga plains around 1000 BC with the PGW, it really affected the plain people from the fifth century BC onwards. But this metal was not derived from the Indus culture. Some archaeologists credit the Harappans with the use of iron whereas others question it.2 In any case though iron and horse may have been known to some Harappans, their mature culture was neither iron-based nor horse-centred. Metallic coinage which played a vital role in the NBPW culture did not have a place in the Indus culture. However, the Northern Black Polished Ware of the Ganga region made its impact on the Black-and-Red Ware and Red Ware associated with the Harappan culture and the post-Indus chalcolithic cultures. At many places in the Ganga zone these two wares are found along with stone and sometimes copper tools in the pre-NJJPW phase, but when they come into contact with the NBPW cultures many of them cease to be coarse in fabric; they become far more refined. Remains of Black and Red Ware and the Red Ware which are found at the Ganga sites in the NBPW phase appear almost the same in respect of fabric and polish. It is for the experts in the archeaology of technology to find out the causes and process of change in the pre-NBPW pottery in the NBPW phase. But the influence of the artisans of the NBPW culture on the pottery tradition of the chalcolithic culture cannot be denied. The Painted Gray Ware departed from the Harappan tradition of pottery. The Harappans practised open kiln firing but the PGW potters practised closed kiln firing. The latter manufactured dishes and bowls which was not the case with the Harappans. The PGW pottery cannot be traced back to any Harappan pottery. The marked feature in the PGW is its de luxe fabric. How it emerged we do not know. Similarly the NBPW did not share the Harappan pottery tradition. However the Red Ware and the Black-and-Red Ware associated with the Harappans continued in the PGW and NBPW phases and were refined and improved by the potters of the two phases. Possibly in the PGW phase their coarse fabric become medium and in the NBPW phase it became fine. The weights and measures of the Harappans are not known in the NBPW area. Thus there is no doubt that the basic elements of the Indus culture do not appear in the Ganga culture associated with the PGW and the NBPW. Neither Red Ware nor Black-and-Red Ware should be considered purely Harappan ware. They were basically chalcolithic ware spread over a large part of the country. However in the doab or the western Ganga zone several sites of