The sea lily meadows
Crinoids carpet the seafloor so densely that whole limestone formations are built from their stems.
- When
- Known to
- ± 10 million years
- Era
- Carboniferous, Paleozoic
Early Carboniferous shallow seas host crinoid gardens on a scale never repeated. Their calcite stems and cups break into disc-shaped fragments that accumulate into thick beds — much of the limestone of the American Midwest and the English Peak District is essentially crinoid debris. The same rock is quarried today for building stone and cement.