PLATE XIV. 



Exogtra poxderosa Koemer (p. 46). 



Ponderous left or lower valve from the Tombigbee sand member of the Eutaw formation (Exogyra ponderosa zone, 

 Mortonicerassubzonei: Plymouth Bluff, Tombigbee River, 4 to 5 miles northwest of Columbus, Lowndes County, 

 Miss. (U. S. Geol. Survey coll. 6451c). This specimen is devoid of costae. 



60 



