Name the flat, longitudinal valleys in the Shiwaliks.
- Shiwalik range is the youngest of the Himalayan ranges facing the plains towards the south and running in a northwest-southeast direction (more in east-west direction) passing through the northern parts of Saharanpur, the southern portion of Dehradun and Garhwal and the middle portion of Nainital district.
- The width of the Shiwalik zone varies from 6 to 30 km (wider in west and decreasing in width towards east). Its height above the mean sea level generally varies between 300 and 700 metre, but the crests vary in height between 750 and 1200 metres.
- The Shiwalik ridges are largely forested. The rivers generally flow across the range through deep gorges.
- Beyond this range, towards the north are flat longitudinal valleys or ‘Duns’ which separate it from the lesser Himalayas.