ABSTRACT
The origin of the Ganges and Indus rivers is much debated. On the evidence of the Siwalik deposits in the Indo-Gangetic Valley, E. H. Pascoe and G. E. Pilgrim advanced the hypothesis of an Indo-Brahm or Siwalik river flowing westward and southward to Sind and draining the vast plains. Post-Siwalik movements are said to have dismembered this river which broke up into the Indus, Ganges and Brahmaputra. Tista Floodplain big sub-region stretches from the high sandy levees of the Dinajpur-Karatoa to the right bank of the Brahmaputra. In the south a long outlier reaches down to Sherpur along the course of the ancient Tista. The Little Jamuna was once a large river, being one of the former channels of the Tista. Its valley is very narrow in Dinajpur District, but south of Hili it is from 5 to 10 miles wide.
