Rudists
From Wikipedia, the free encyclopedia
Rudists are a group of bivalves that peaked in abundance and diversity during the late Mesozoic era, particularly in the Cretaceous period, at the end of which they became extinct. Their "classic" morphology consisted of a lower, roughly conical valve that was attached to the seafloor or to neighboring rudists, and a smaller upper valve that served as a kind of lid for the organism.
Their classification as true reef-builders is controversial, yet they were one of the most important constituents of reefs during the Cretaceous period.[1] At one point, rudist reefs fringed the North American coast from the Gulf of Mexico to the present-day Maritime Provinces. Because of their high porosity, rudist reefs are highly-favored oil traps.
