Bryolith //top\\

: Their rounded shape implies consistent movement by waves or currents strong enough to tumble the nodules.

: The crab provides the bryozoan with mobility and protection from burial in sediment, while the bryolith offers the crab a sturdy, expanding domicile that may reduce the need to find new shells. Ecological and Geological Importance bryolith

He realized then that the Bryolith wasn't a resource to be mined, but a teacher waiting for a student. He switched off his drill and reached out a gloved hand. : Their rounded shape implies consistent movement by

: The bryozoan colony follows the spiral shape of the shell, often extending the aperture and providing a growing home for the crab. He switched off his drill and reached out a gloved hand

| | Description | |--------------------------|---------------------------------------------------------------------------------| | Definition | Bryozoan-encrusted, rolled nodule | | Size range | 0.5 – 10 cm (rarely larger) | | Shape | Subspherical to ellipsoidal, often lumpy | | Growth mechanism | Alternating encrustation and overturning | | Key identification | Zooidal pores, asymmetrical crusts, sediment-filled growth interruptions | | Environment | Shallow marine (0–50 m), moderate energy, often seagrass or sand | | Geological range | Jurassic? → Cretaceous → common in Cenozoic | | Economic use | Biogenic carbonate, minor building stone, paleoenvironmental indicators |