Here's why:
* Geologic maps depict the distribution of rock units and geologic structures at the Earth's surface.
* They use symbols, colors, and patterns to represent different rock types, their ages, and their orientations.
* They often include information about faults, folds, and other geologic features that can be used to infer the underlying structures.
While other maps might show some underground features, a geologic map is specifically designed to illustrate the subsurface geology.
