Duns are longitudinal valleys that formed when the Eurasian and Indian plates clashed due to folding.
They formed among the lower Himalayas and Shiwaliks.
The coarse alluvium carried down by Himalayan rivers collected in the valleys.
Final Answer:
Dims are the longitudinal valleys that run between the lower Himalayas and the Shivaliks.
Dehra Dun, Kotli Dun, and Patti Dun are among the well-known Duns.