St. Maurice and Claiborne Pelecypoda 215 



PLATE 14 

 ^gure Page 



1. Peden zvautubbeanus Dall, X 2 21 



Right valve, common form, showing tripartite subdivision of 

 ribbing near the basal margin ; lack of strong ribbing over 

 much of the surface of the valve. Wautubbee, Miss. 



2. The same, X 2 ; showing well defined but unornamented rib- 

 bing in umbonal region. Hickory, Miss. 



3. The same, X 2, left valve. Notice the simple ribbing till the peri- 

 pheral region is reached ; also the well marked ornamenta- 

 tion of ribs throughout. Hickory, Miss. 



4. The same, right valve ; X 1.5 ; interior. 



5. Ya.rie.ty oi zuautubbia7ius, X 1.6 23 



Large, very thin, with dual subdivision of costae. From the 

 basal beds, Claiborne Bluff. 



6, 7. Variety zvillcoxi Dall, X 3 23 



From specimens furnished by the U. S. Nat. Mus. , from "Eo- 

 cene, Clark Co., Ala." 



8. Variety c^azw^z Harris, X 2.2 24 



Right valve, from Wautubbee, Miss. 



9. Peden piclckricosta 'Mr. and Aid., X 2 24 



Showing characteristics mentioned by the describers. Wautub- 

 bee, Miss. 



10. The same, X 2.5, left valve, showing characteristictics men- 

 tioned by Dall (Tr. Wag., p. 730), Wautubbee, Miss. 



11. Peden {darkeanus? var. ) burlesonensis, n. var., X 2 26 



From a specimen furnished by the U. S. Nat. Mus. , from 

 "Black Bluff Shoals", Brazos River, Texas. 



12. The same, X i}i. From "Burleson Bluff", Brazos River, Tex. 



13. The same, X i>^. From ^"Collier's Ferry", Brazos River, 

 Texas State Museum specimen. 



