Bivalves: Hinged with Two Shells
Fossil Invertebrates

Bivalves include the clams and mussels that we are familiar with today, and a less diverse fauna in the Devonian. These are mollusks that form their hard shells from the mineral aragonite. The word "bivalve" comes from the fact that these animals have two shells that are mirror opposites of each other, termed valves. See section on brachiopods.