Immovable or fixed hard rocks or boulders could be considered as monuments of permanent nature to be used in defining and marking corners when it has a diameter of the exposed surface of more than how many meters?

• A. 0.5 m
• B. 1 m
• C. 2 m
• D. 0.2 m

Answer: (B)

For a natural rock feature to serve as a permanent corner monument, it must be clearly identifiable and robust enough to remain fixed over time. When the exposed surface diameter of the rock is more than one meter, the feature provides sufficient mass, stability, and visibility to resist weathering, disturbance, and routine ground changes, making it a reliable reference for defining corners in surveying. If the diameter is smaller, the rock can be weathered, chipped, or moved, compromising the corner position, so it wouldn’t be treated as a permanent monument. A two-meter diameter is not necessary for the standard and would exceed what’s required, whereas very small diameters like half a meter or a fifth of a meter would be unreliable. Hence, the threshold is one meter.