The longitudinal valleys lying between the Lesser Himalaya ranges and the Shiwalik hills are collectively known by which name?

Introduction / Context:
The Himalayan mountain system has a complex structure that includes different ranges and intervening valleys. Understanding the arrangement of these ranges and the terminology used for each feature is an important part of Indian physical geography. This question focuses on the long, narrow valleys that lie between the Lesser Himalaya and the Shiwalik hills, asking you to recall the specific term used for them.

Given Data / Assumptions:

• The key features are Lesser Himalaya (also called Himachal) and Shiwalik hills (Outer Himalaya).
• The question mentions longitudinal valleys between these two ranges.
• The options are Shiwaliks, Himadri, Himachal, and Duns.
• We assume standard classification of Himalayan physiographic divisions.

Concept / Approach:
The Himalaya are broadly divided into the Inner or Great Himalaya (Himadri), the Lesser Himalaya (Himachal), and the Shiwalik range. Between the Lesser Himalaya and the Shiwalik hills lies a series of longitudinal valleys, which are called Duns. Examples include Dehra Dun, Kotli Dun, and Patli Dun. These valleys are often filled with thick deposits of coarse sediments and have fertile land. By recalling this terminology, we can quickly identify the correct option.

Step-by-Step Solution:
Step 1: Recall the three major parallel ranges of the Himalaya: Himadri (Great Himalaya), Himachal (Lesser Himalaya), and Shiwalik (Outer Himalaya). Step 2: Remember that between the Lesser Himalaya and the Shiwalik hills, long narrow valleys are formed. Step 3: These valleys are known as Duns and often have names ending with Dun, such as Dehra Dun. Step 4: Check the options and recognise that Duns is the only term that refers to valleys, while the others refer to ranges. Step 5: Conclude that these longitudinal valleys are collectively called Duns.

Verification / Alternative Check:
To verify, think of Dehra Dun, a well known city in Uttarakhand, which literally lies in a Dun valley between the Lesser Himalaya and the Shiwalik range. Geography textbooks point out that such valleys contain thick deposits of gravel and alluvium and are called Duns. Himadri refers to the highest snow clad range, while Himachal and Shiwalik refer to the middle and outer ranges respectively. None of these names are used for the valleys themselves, confirming that Duns is the correct answer.

Why Other Options Are Wrong:
Shiwaliks is wrong because it is the name of the outermost range of the Himalaya, not the valleys. Himadri is wrong because it refers to the Great Himalaya, the highest and innermost range. Himachal is wrong because it denotes the Lesser Himalaya, not the valleys that lie between Lesser Himalaya and Shiwalik. All three are names of mountain ranges, whereas the question is clearly about the intervening longitudinal valleys.

Common Pitfalls:
Students often confuse the terms Himachal and Himadri or use Shiwalik loosely for foothill regions. This can lead them to choose a range name instead of the correct valley term. Another pitfall is to think that Dun is just part of a city name like Dehra Dun, rather than a geographical term for a type of valley. To avoid confusion, it helps to memorise the sequence: Himadri (highest range), Himachal (middle range), Duns (valleys), Shiwalik (outer range).

Final Answer:
The longitudinal valleys between the Lesser Himalaya and the Shiwalik hills are known as Duns.