from the GNU version of the Collaborative International Dictionary of English
- n. A genus of Cretaceous fossil shells allied to oysters.
Sorry, no etymologies found.
The specimen submitted to analysis was taken near the upper part of the bed, about four feet above the line, along which the exogyra are the most numerous.
They are found in those beds for the same reason that the exogyra costata of the green sand is also found in the miocene.
Leopold von Buch has discovered exogyra and trigonia in the southern hemisphere (volcano of