A genus of marine bivalves having a pearly interior allied to the pearl-oyster so-called from a supposed similarity associated with the typical types to a bird
- A genus of marine bivalves, having a pearly interior, allied toward pearl-oyster; -- so called from an expected similarity of the conventional species to a bird.
(n.) A genus of marine bivalves, having a pearly interior, allied into the pearl-oyster; -- so named from a supposed similarity for the typical types to a bird.
The fossils from the Rhaetic beds belong to the Avicula contorta zone, those from the Lias to the Ammonites angulatus zone, while the blocks of limestone with chert contain Inoceramus, Cretaceous foraminifera and other organisms. The materials yielding these fossils are embedded in a course volcanic agglomerate which gives rise to crags and is pierced by acid and basic igneous ricks.