EXPLANATIONS OF TLATE I. 



Fig. I. a, b. . ■ . Ltngtilepis nNNiFOUMis. ...... 2 



1 a. Ventral valve of a broart specimen — worn and exfoliateil. 



1 b. A narrower specimen," iu same condition. 



l'"ijr. 2. a, b. . . LiNc.tTLF.ris prima. ....... 3 



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



2 b. Same enlarged. 



Fig. 3. a, b, c, d Obolella nana 4 



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



3 b. Same enlarged. 



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

 3 </. Same enlarged. 



Pig. 4 Agraulos ? 10 



Fig. 5. a, b, c, d, e. . . . . Chonetes mucronata. ...... 22 



5 a. Exterior of ventral valve, natural size. 



5 6. Interior of same. 



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



5 d. Inside view of dorsal valve. 



5 e. Enlargement of surface strife. 



Fig. 6. a, b, c, d, e, f, g, h, i. . . Fusulina cylindrica. 14 



6 a. Outline, natural size. 



(i b. Magnified section of same across the middle. 



ti c. A jiortiou of same very highly magnified, showing the foramina. 



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



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



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



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



within. 

 G /i, i. Outline view of another variety, natural size. 



Fig. 7. a, b, c, d. . . . IIemipronites crassus. . . .' . . .26 



7 a. Outside view of ventral valve. 



7 b. 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. 



Fig. 8. a, b Sedgwickia? concava 41 



8 «. A side view of a cast. 



8 b. Outline dorsal view of same. 



Fig. 9 Sedgwickia? altirostrata 41 



Fig. 10. a, b Allorisma subcuneata 37 



10 a. A doi'sal view of an internal cast. 



10 b. Side view of same, showing muscular and pallial impressions. (The latter too sharply defined 



in the lithograph.) 



Fig. 11. o, 6. . . . . Pleurophorus occidentalis. ...... 35 



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 

 antero-ventral margin not being made sufficiently prominent. 



11 b. Dorsal outline profile of same. 



Fig. 12. a, b. . . Myalina perattenuata 32 



12 rt. Side view of .in adult specimen retaining most of the shell. 

 12 b. An internal cast of a young specimen. 



Fig. 13 Pleurotomaria subturbinata. 47 



Fig. 14. a, b Pleurotomaria iiumerosa 46 



14 a. Front view. 



14 b. Opposite view of same. 



