EXPLANATIONS OF PLATE I. 



Fig. 

 Fig. 

 Fig. 



Fig. 

 Fig. 



Fig. 



Fig. 



Fig. 



Fig. 

 Fig. 



Fig. 



Fig. 



Fig. 

 Fig. 



lab.. LlNOULEPIS PINNIFORMIS. 



1 a. Ventral valve of a broad specimen worn and exfoliated. 



1 4. A narrower specimen, in same condition. 



2. a , b. LlNGULEPIS PRIMA. . 



2 a. Ventral valve, natural size, somewhat worn. 



2 4. Same enlarged. 



3. a, b, c,d OBOLELLA NANA. 



3 a. Ventral? valve, natural size (exterior). 

 3 4. Same enlarged. 



3 c. Interior of another specimen of same, natural size. 

 3 d. Same enlarged. 



4. ...... AGRAULOS ? . 



5. o, b, c, d, e CHONETES MUCRONATA. 



6 a. Exterior of ventral valve, natural size. 



5 4. Interior of same. 



5 c. Outline profile view of the two valves united. 



5 rf. Inside view of dorsal valve. 



5 e. Enlargement of surface striae. 



6. a, b, c, d, e, f, g, h, i. . . FUSULINA CYLINDRICA. 



6 a. Outline, natural size. 



6 4. Magnified section of same across the middle. 

 6 c. A portion of same very highly magnified, showing the foramina. 

 6 d. An outline of var. ventricosa, natural size. f 

 6 e. (c. by mistake on the plate.) Same enlarged. 

 6/. A profile or end view of same enlarged. 



6 q. An outline of same enlarged, with a portion of the outer shell removed to show the waved septa 

 within. 



6 A, t. Outline view of another variety, natural size. 



7. a, b, c, d. . . . HEMIPRONITES CRASSUS. 



7 a. Outside view of ventral valve. 



7 4. Internal view of same, with its cardinal area, and closed foramen. 

 7 c. Outline of the two valves united, as seen in a side view. 



7 d. Part of the hinge and interior of a dorsal valve, showing the cardinal process. 



8. a, 6 SEDGWICKIA? CONCAVA. 



8 a. A side view of a cast. 



8 4. Outline dorsal view of same. 



9 SEDGWICKIA? ALTIROSTRATA 



10. a, 6 ALLORISMA SUBCUNEATA 



10 a. A dorsal view of an internal cast. 



10 4. Side view of same, showing muscular and pallia! impressions. (The latter too sharply defined 



in the lithograph.) 



11. o, b. . . . . PLEUROPHORUS OCCIDENTALS. .... 



11 a. Side view of a cast of left valve. The drawing of this figure is not accurately copied in the 



lithograph, it represents the beak too prominent, and too attenuate, in consequence of the 

 anterc-ventral margin not being made sufficiently prominent. 



11 4. Dorsal outline profile of same. 



12. a, b. . . . MYALINA PERATTENUATA. . . 



12 a. Side view of an adult specimen retaining most of the shell. 

 12 4. An internal cast of a young specimen. 



13. . PLEUROTOMARIA SUBTURBINATA. .... 



TAOF. 

 2 



10 



22 



14 



14. a, b. . 

 14 a. Front view. 

 14 4. Opposite view of same. 



PLEUROTOMARIA IIUMEROSA. 



26 



41 



41 

 37 



35 



32 



47 

 46 



