Geographical settings of Zone IV

This zone comprises North Bengal including that part of the Mahananda Plains comprising the modern districts of Darjeeling, Jalpaiguri, Cooch Behar, North and South Dinajpur and Malda besides, the Rangpur and Rajsahi divisions of Bangladesh (mainly the districts of Dinajpur and Rajsahi) (Fig. 2.10).

Geographically, it comprises of the Barind tract, one of the several Pleistocene terraces within the Bengal Basin and the floodplains, which are mostly old courses of rivers Padma, Mahananda, Purnabhava, Atrai, Tista and Karatoya (Rashid, op. cit,: 12-20). Three types of physiographic formations are discernible here, i.e., the plain, the tarai and the Himalayan belt (Chakrabarti 2001: 58-73). The plain comprise the three districts of West Bengal i.e., South and North Dinajpur and Malda and the two districts of Bangladesh i.e., Dinajpur and Rajsahi. These two districts of Bangladesh are in sense eastern extensions of Dinajpur and Malda districts of West Bengal. The soil is mostly alluvial clayey though, the old alluvial formation of Barind, which is of a pale reddish-brown hue and looks yellowish when weathered, is mixed with ferruginous concretions and Kankar gravel (ibid.). Mahananda is the main river in this section and the western bank of the river is composed of new alluvium and is generally low, subject to floods. On the other hand, the eastern section is covered by the old alluvial tract of Barind.