Final answer:
Navajo sandstone consists of massive columnar joints and cross-beds, which are important geological features.
Step-by-step explanation:
Navajo sandstone consists of massive:
- Columnar joints: These are vertical fractures that form in rocks, creating a series of regular parallel columns.
- Cross-beds: These are horizontal layers of sediment that are inclined or tilted relative to the main bedding plane.
These features are commonly observed in sandstone formations and can provide important clues about how the rocks were formed and the geological processes that occurred over time.