SIWALIK HILLS

also called Siwalik Range, or Outer Himalayas, sub-Himalayan range, extending west-northwestward for more than 1,000 miles (1,600 km) from the Tista River, Sikkim (India), through Nepal, across northwestern India, and into northern Pakistan. Though only 10 miles (16 km) wide in places, the hills have an average elevation of 3,000 to 4,000 feet (900 to 1,200 m). They rise abruptly from the plain of the Indus and Ganges rivers (south) and parallel the main range of the Himalayas (north), from which they are separated by valleys. The Siwaliks are sometimes considered to include the southern foothills of the Assam Himalayas, which extend eastward for 400 miles (640 km) across southern Bhutan to the bend of the Brahmaputra River. The range proper, to which the name Siwalik (from Sanskrit, meaning Belonging to Siva) was formerly restricted, is the 200 miles (320 km) of foothills extending from Hardwar, India, on the Ganges River northwestward to the Beas River. Everywhere in this section the poor scrub forests have long since been removed, and the hills are subject to severe erosion. Periodic floods sweep masses of sand and silt down into ever-changing great stream beds, called cos, that are dry except after rains. The Nepal portion of the hills is called the Churia Range.