How do vertical shafts differ from solution chimneys in caves?

In the study of caves, vertical shafts and solution chimneys are distinct features formed by the dissolution of limestone in the unsaturated zone. They differ primarily in their formation processes and physical characteristics:

• Formation and Control: Solution chimneys develop along vertical fractures or bedding planes of vertically bedded limestones. In contrast, vertical shafts are controlled by the hydraulic forces of freely flowing water.
• Shape and Appearance: Solution chimneys tend to be irregular in cross-section and elongated along the controlling fracture or bedding plane. They may be offset or descend at steep angles depending on the pitch of the guiding fracture. Vertical shafts are typically nearly perfect cylinders with circular cross-sections. Their walls are vertical and cut across limestone beds regardless of the angle or composition of the rock.

Both features are independent of the main conduit system, though they may connect to active horizontal conduits via small drain passages. When they intersect multiple tiers of horizontal passages, they serve to integrate the cave system.1