Match List I with List II and select the correct answer using the code given below the Lists: List I (Drainage Pattern of River) A. Insequent B. Consequent C. Subsequent D. Resequent List II (Feature) 1. Whose direction of flow is controlled by the rock structure 2. No apparent reason why it follows the path it takes 3. Flow in the same direction as the consequent stream but at a lower level 4. Whose course is determined by the original slope of the land Code:
- (a)A-2 B-1 C-4 D-3
- (b)A-2 B-4 C-1 D-3
- (c)A-3 B-4 C-1 D-2
- (d)A-3 B-1 C-4 D-2
Correct — B, A-2 B-4 C-1 D-3. Take the four names in the order the definitions come. A consequent stream is one whose course is a direct consequence of the original slope of the land it began on, so B goes to statement 4. A subsequent stream is one whose course has been determined by headward erosion working selectively along a belt of weak rock, so its direction is controlled by the structure — C goes to statement 1. A resequent stream follows the original relief but at a lower level than the original slope, running the same way as the consequent stream below it, so D goes to statement 3. An insequent stream has an almost random course with no visible structural or slope control, which leaves it with statement 2 — no apparent reason why it follows the path it takes — and so A goes to 2. Only option (b) carries that whole set.
- (a)A-2 B-1 C-4 D-3 — Gets the insequent and resequent ends right and then swaps the middle pair, handing the consequent stream the structural control and the subsequent stream the original slope. It is the reverse of the truth — the consequent came first and followed the slope; the subsequent came later and followed the weak rock.
- (c)A-3 B-4 C-1 D-2 — Correct on the consequent and subsequent streams but exchanges the two ends. It makes the insequent stream the one flowing below the consequent, and the resequent stream the one with no apparent reason for its path — which drops the meaning of the prefix re.
- (d)A-3 B-1 C-4 D-2 — Wrong on all four. It is what a candidate produces by pairing the list in order without reading the descriptions.
This is the genetic classification of streams, which asks how a stream came to run where it does rather than what shape the network makes on a map. A consequent stream is the first to appear on newly emerged land and simply runs downhill. As it cuts down it exposes bands of harder and softer rock, and tributaries then eat headward along the soft bands — those are the subsequent streams, and they usually join the consequent at a sharp angle, which is what produces a trellis pattern. A resequent stream drains into a subsequent valley in the same direction as the original consequent but at a lower level; an obsequent stream, not offered here, runs the opposite way, back up the scarp face.
Work from the prefixes and the item almost solves itself. Consequent follows from the slope, sub means beneath and later along the underlying structure, re means again in the original direction, and in as a negative gives a stream that follows nothing in particular. One point about the printed wording is worth noting honestly: List I is headed Drainage Pattern of River, whereas insequent, consequent, subsequent and resequent are types of stream classified by origin. Drainage patterns proper are the shapes — dendritic, trellis, radial, centripetal — and a CDS paper of 2024 asks about those separately. The mismatch in the heading does not change what is being matched.
- A consequent stream follows the original slope of the land surface on which it developed.
- A subsequent stream develops later, its course fixed by selective headward erosion along weak strata.
- A resequent stream follows the original relief but at a lower level, in the same direction as the consequent.
- An obsequent stream flows opposite to the consequent drainage.
- An insequent stream has an almost random course with no apparent structural control, often forming a dendritic pattern.
The prefixes carry the whole classification — with, beneath, again, and not at all.
- Reading a genetic classification of streams as a list of drainage patterns.
- Swapping consequent and subsequent; the consequent came first and followed the slope.
- Forgetting the obsequent stream, which is the one that runs against the consequent.
As a matching item like this one, or as a single-line definition question on one of the four names.
Identify the type of drainage pattern on the basis of the given characteristics : 1. It represents the most common pattern of streams and their tributaries. 2. It occurs in areas of uniform rock type and regular slope. 3. A map, or aerial photograph, shows a pattern like the veins on a leaf—smaller streams join the main stream at an acute angle. Select the correct answer.
- (a) Dendritic
- (b) Radial
- (c) Trellis
- (d) Centripetal
Answer(a) Dendritic
The companion classification. That item asks for the shape a network makes on a map, this one for how each individual stream came to run where it does — and the two meet at the insequent stream, which lacks structural control and therefore tends to produce exactly the leaf-vein dendritic pattern described there.
- practice — not a real PYQ
A stream whose course has been determined by headward erosion along a belt of weak rock is called
- (a)a consequent stream
- (b)a subsequent stream
- (c)a resequent stream
- (d)an obsequent stream
Answer(b) a subsequent stream — it develops after the consequent and is guided by the rock structure.
- practice — not a real PYQ
A stream that flows in a direction opposite to that of the consequent drainage is termed
- (a)insequent
- (b)resequent
- (c)obsequent
- (d)subsequent
Answer(c) obsequent — the prefix ob carries the sense of against, as against re for the same direction at a lower level.