A hymn to the Ganga would have been considered an appropriate beginning by the people belonging to the period we are to study in this section. In their consciousness, in their depiction of the river in art and literature, perhaps there is more than just religious veneration. It is the Ganges river system, together with the Brahmaputra further east, which shaped the human geography and economic life of eastern India. It is beyond our purview to analyse the ecological factors of the deltaic region and we may take aspects of deltaic man-nature interaction as constant. But we must note some important changes that took place or culminated in the eighteenth and early nineteenth centuries in Bengal river systems. Comparison of maps, revenue and survey reports and various travellers' accounts help us form roughly the following picture of changes as a result of cataclysmic events like the earthquake of 1762 and major inundations of 1769 and 1786–8, as well as cumulative effects of changes in the upper reaches of river systems: the Tista moved to the east, perhaps in 1786–8, and the Mahananda, Karatoya and Atrai declined; ports mentioned by Buchanan-Hamilton on the Atrai disappeared into oblivion. In the north-west the Kosi worked its way westwards. In western Bengal the Bhagirathi river system declined; the Bhagirathi was not navigable throughout the year according to Rennell (1781) and Colebrooke (1794). The Hugly was the artery of trade. In Central Bengal the silting-up of rivers and oscillation in river courses was observed in Murshidabad and Nadia; the decline of Murshidabad town was partly for this reason.