EXOGYBA PONDEBOSA ZONE. 



27 



range render it a characteristic form possessing value in correlation. The appropriateness of 

 the name Exogyra ponderosa to designate the zone in which the species occurs is, therefore, 

 apparent. The species, including its varietal form Exogyra ponderosa var. erraticostata Steph- 

 enson, has been found at 6.9 authentic localities in the belt of outcrop of the zone in the eastern 

 Gulf region. By detailed collecting this number could be multiplied many times. 



Within the stratigraphic limits of the zone of Exogyra ponderosa in the eastern Gulf region 

 the following 99 species (questionably 103) are known to occur: 



Fossils from zone of Exogyra ponderosa. ' 



Echinodermata: 



Cassidulus subquadratus Conrad, a be. 

 Vermes : 



Serpula cretacea (Conrad), a be. 



S . sp . (nearly straight tube) . a be. 



Hamulus onyx Morton, a be. 



H. squamosus Gabb. a be. 



H. major Gabb. be. 

 Mollusca: 



Nucula percrassa Conrad . a be d. 



N. eufalensis Gabb. a be. 



N. sp. (ci. undescribed species from Snow Hill, 

 N. C). be. 



Leda pinnaforma Gabb. a be. 



L. longifrons Conrad, a be. 



L. pro texta Gabb. a be. 



Perrisonota pro texta Conrad, a be. 



Cucullaea carolinensis (Gabb). be. 



Trigonoarca maconensis (Conrad), be. 



Breviai'ca umbonata (Conrad). 6c. 



Nemodon brevifrons Conrad, a be. 



N. sp. nov. 6c. 



Barbatia lin tea Conrad. 6c 



Glycymeris subaustralis (D'Orbigny). a be. 



Gervilliopsis ensiformis (Conrad), a be. 



Pernasp. nov. (found at Broken Arrow Bend, Ala.-Ga., 

 etc.). bed. 



Ostrea plumosa Morton, a be. 



0. tecticosta Gabb. a be. 



O. larva Lamarck, a be. 



O. cretacea Morton. 6c d. 



0. diluviana Linnseus. 6c. 



O. panda Morton, a be. 



0, sp. nov. (large). 6c. 



O. sp. nov. (first found at House Bluff, Ala.), bed? 



O. sp. nov. (also found at Blue Banks Landing, N. C, 

 etc.). 6c. 



O. sp. nov. (very irregular), a be. 



0. sp. nov. (from near Hatchechubbee). 6c. 



Gryphtea vesicularis Lanrarck. a be. 



G. vomer (Morton), a be. 



G. aucella Roemer. 6c. 



G. sp. (smooth, convex), be. 



Exogyra ponderosa Roemer. 6c. 



E. ponderosa var. erraticostata Stephenson. 6c. 



Trigonia eufalensis Gabb. a be. 



T. sp. nov. (also found at Snow Hill, N. G, etc.). 6c. 



Pecten quinquecostatus Sowerby. a be. 



P. argillensis Conrad, a be ? 



P. simplicius Conrad, a be. 



Mollusca — Continued. 



P. burlingtonensi3 Gabb. 6c. 



P. quinquenarius Conrad, a be. 



P. sp. nov. (also found at Snow Hill, N. G, etc.). 



bed. 

 Lima reticulata Forbes, a be. 

 L. pelagica (Morton). a6cf 

 Anomia argentaria Morton, a be. 

 A. lin tea Conrad, a f be. 



A. sp.nov. (also found at Snow Hill, N. C, etc.). bed. 

 Paranomia scabra (Morton) . a be. 

 Cymella bella Conrad, a be. 

 Liopistha alternata Weller. 6c. 

 L. sp. (aff. L. alternata Weller). 6c. 

 Veniella conradi (Morton), a be. 

 Etea carolinensis Conrad . a 6c d. 

 Eriphyla conradi (Whitfield). 6c. 

 Vetericardia crenalirata (Conrad), a be. 

 Crassatellites carolinensis Conrad . 6c ? 

 C. sp. nov. 6c. 



Scambula perplana Conrad, a be. 

 Radiolites austinensis Roemer. 6c. 

 Arena carolinensis Conrad. 6c. 

 Lucina glebula Conrad. 6c. 

 Tenea pinguis (Conrad), a be. 

 Cardium eufaulense Conrad, a be. 

 C. spillmani Conrad, a be. 

 C. alabamense Gabb. a be. 

 C. dumosum Conrad, a be. 

 Isocardia cliff woodensis Weller. 6c f 

 Cyprimeria depressa Conrad . a be d. 

 C. alta Conrad, a be. 

 C. densata (Conrad), a be. 

 Aphrodina regia Conrad. 6c. 

 Cyclothyris alta Conrad. 6c. 

 Legumen planulatum (Conrad), a 6c. 

 Baroda carolinensis Conrad. 6c. 

 Linearia metastriata Conrad, a be. 

 Linearia? ornatissima Weller. a be. 

 Leptosolen biplicata (Conrad), a be d. 

 Cymbophora lintea (Conrad), a be d. 

 Schizodesma appressa Gabb. a be. 

 Corbula crassiplica Gabb. a be. 



C . carolinensis Conrad . 6c d. 

 Panopea decisa Conrad, a be: 

 Gastrochsena aniericana Gabb. a be. 

 Dentalium ripleyanum Gabb. a be. 



D. sp. nov. a be. 



Cadulus obnutus (Conrad), a be. 



Lunatia obliquata Meek and Hayden. o 6c. 



1 a, Exogyra costata zone; be, Exogyra ponderosa zone as a whole, not necessarily both subzones; i, basal beds of Emavr formation. 



