Crinoids flourished because they were filter feeders, and most of the particles in the clear oceans would have been bits of food. One can imagine the crinoids growing in extensive marine meadows, rippling in the waves on their long, thin, graceful columns, like garden flowers in the wind. On rare occasions, they were preserved whole, flattened to the bottom by a storm and quickly covered with lime mud. The Burlington contains more species of crinoids than any other fomration in the Mississippi Valley. About 260 species have been identified, some of which may be descriptions studied only casually.
Brachiopods are next in abundance.
About 110 species have been identified. Bryozoa are abundant but only a few speicies have been recognized. Blastoids are more abundant in the Burlington than any other formation in Missouri. Colonial corals declined in some areas, but solitary corals were diversified and abundant. Gastropods, pelecypods and cephalopods are rare.