ILLUSTRATIONS. 



Page. 

 Plate I. A, Lower Cretaceous sands and clays overlain unconformably by Pleistocene terrace gravels, sands, 

 and sandy loams, Coosada Bluff, Alabama River, 11 miles north of Montgomery, Ala. ; B, Uncon- 

 formable contact between Lower Cretaceous clay and basal sands of the Eutaw formation, cut 



in Seale Road, 4 miles southwest of Columbus, Ga., in Russell County, Ala 10 



II. A, Tuscaloosa formation, consisting of sands and clays with interbedded ferruginous layers, Huntsville 

 road, H miles east of Cottondale, Tuscaloosa County, Ala. ; B, Laminated sands and clays of the 

 Eutaw formation, bluff at Z. Logan's landing, TVarrior River, Hale County, Ala., 8i miles (by 



the river) above the Alabama Great Southern Railroad bridge 12 



III. A, Typical beds of the Tombigbee sand member of the Eutaw formation, Plymouth Bluff, Tombigbee 

 River, Lowndes County, Miss.; B, Laminated sands and clays of Coffee sand member of the 



Eutaw formation, bluff just above Pittsburg Landing, Hardin County, Tenn 13 



IV. A, Basal marine beds of the Eutaw formation, Broken Arrow Bend, Chattahoochee River, Alabama 

 side, 10i miles (by the river) below Columbus, Ga.; B, Beds of the Tombigbee sand member of 

 the Eutaw formation as developed in the Chattahoochee region, Banks Landing, Chattahooche 



River, 26i miles (by the river) below Columbus, Ga 14 



V. A Typical exposure of the Selma chalk, Jones Bluff, Tombigbee River, near Epes, Sumter County, 



Ala. ; B, Selma chalk at its type locality, Alabama River, Selma, Ala 16 



VI. A, Classic fossil locality of the Ripley formation, bluff on Owl Creek, 3 miles northeast of Ripley, 

 Tippah County, Miss.; B, Beds of the McXairy sand member of the Ripley formation, cut of 



Southern Railway 1} miles west of Cypress. McXairy County, Tenn 17 



VII. A. Marine beds of the Ripley formation. Chattahoochee River, Eufaula, Ala.: B. Marine beds of the 

 Ripley formation, cut of Louisville & Xashville Railroad If miles north of Fort Deposit, 



Lowndes County, Ala 18 



VIII. A. Cusseta sand member of the Ripley formation overlain by typical marine beds of the formation, cut 

 of Seaboard Air Line Railway at Hicbitee I Manta station i. Chattahoochee County, Ga. ; B, Beds 

 of Providence sand member of the Ripley formation, gully near Eufaula-Lumpkin Road, KM 



miles northeast of Georgetown. Ga 19 



IX. Geologic map of Cretaceous deposits of the eastern Gulf region In pocket. 



X. Diagram showing the lithologic variations and age relationships of the Cretaceous deposits of the east- 

 ern Gulf region and their correlation with the Carolina and Xorlh Atlantic Cretaceous 20 



XI. Specimens of Exogyra and other fossils weathered from Selma chalk: A, "Bald Knob," 3 miles west 



of Corinth, Alcorn County. Miss. : B, One mile west of Cotton Gin Port. Monroe County, Miss. . 20 



XII. Diagram showing the ranges in the Atlantic and Gulf Coastal Plain of the species and varieties of 



Exogyra described in this paper 44 



XIII. Exogyra upatoiensis and Exogyra ponderosa Roemer 58 



XIV. Exogyra ponderosa Roemer 60 



XV. Exogyra ponderosa Roemer and Exogyra ponderosa var. erratieostata var. nov 62 



XVI. Exogyra ponderosa var. erratieostata var. nov. and Exogyra costata Say 64 



XVII. Exogyra costata Say 66 



XVIII. Exogyra costata Say 68 



XIX. Exogyra costata Say 70 



XX. Exogyra costata Say and Exogyra costata var. eancellata var. nov 72 



XXI. Exogyra costata var. eancellata var! nov 7 1 



Figure 1. Generalized section showing fossil zones and subzones in the eastern Gulf Upper Cretaceous deposits. . 23 



2. Sketch map showing areas of paleontologic collections listed in Tables 1 to 8 24 



6 



