Contours that coalesce (pile up) on a map indicate which landform?

• A. Cliff, bluff, escarpment
• B. Valley, basin, trough
• C. Plateau, mesa, butte
• D. Ridge, spur, knob

Answer: (A)

When contour lines coalesce, it signals a very steep or near-vertical change in elevation over a short distance. The lines bunch tightly along a narrow face, indicating a sharp drop or cliff. That pattern best matches landforms with abrupt edges like cliffs, bluffs, or escarpments, where the terrain plunges steeply and the contour lines bunch up in a small horizontal space.

Valleys and basins show gentler, bowl- or V-shaped depressions with lines bending toward higher ground and typically spaced more widely where the slope isn’t as steep. Plateaus and mesas have flat or gently sloped tops with lines that run parallel, while ridges and knobs create elongated high ground with contour lines wrapping around rather than piling up on a single face.