'Ig. 



PLATE 79. 



1. 133. 7. LiNGULA QUADRATA. (Pag. 285.) 



1 a, b. Figures of two specimens, showing the difference ordinarily seen in the form of this fossil. 

 1 c. A portion of the surface magnified. 



Fig. 2. 141. 4. Leptjena alternata. (Pag- 286.) 



2 a. Mould of the interior of the convex valve of this species, showing the form of the visceral impression, 



the oblique teeth, etc. The nasute character is well preserved. 

 2 b. Figure of a similar specimen, where the nasute cliaracter is less conspicuous. 

 2 c. A smaller specimen of the same character, showing a slight contraction in front. 

 2 d. A portion of the surface of one of these enlai-ged, showing the striato-punctate character. 

 2y. The impression made by the outside of the convex valve of this species, showing the fascicles of striae in 



a perfect manner. 

 2f*. A cast of a large symmetrical specimen, showing the same characters of the surface, form of visceral 



impression, etc. 

 2 g. A small specimen, preserving the shell, and showing the stria? in interrupted fascicles. 

 2 g\. A portion of the surface enlarged. 

 2 h, i. Figures of specimens which still preserve a part of the shell, having the stria; in broad fascicles of 



small ones separated by larger ones. 

 2 k. Interior of the ventral valve, showing two small teeth on the hinge line, with three diverging callosities. 



2 /. Mould of the interior of the ventral valve, showing the two cavities made by the teeth, and tile impressions 



of the radiating callosities. 



Fig. 3. 146. 9. LEPTiENA sEEicEA. ( Pag. 287.) 



3 a. A mould of the interior of the shell. 



3 b. An enlarged portion, showing the striato-punctate character of the surface. 



3 a*. Another specimen, presenting more distinctly the usual character of casts of this species. 



Fig. 4. 155. 2. Orthis testudinaria. (Pag- 288.) 



'1 a, b. Casts of tiie interior of the dorsal valve. 4 c. Cast of the interior of the ventral valve. 



A d. A similar cast, more strongly impressed by the striae. 



4 e. A fragment of the impression of the outer side of the ventral valve, showing the fine concentric strise, 



which crenulate the diverging striae. 



Fig. 5. 341. 19. Orthis EERATicA. (Pag. 288.) 



5 a, b. Dorsal and ventral views of the cast of a large specimen. 5 d. Ventral view of a small specimen. 

 3 c. Front view of a larger specimen. 5 e. Cardinal view of a large specimen. 

 5f. Profile view of a moderately convex specimen. 



Fig. 5*. 342. 20. Orthis centrilineata. (Pag. 289.) 



.5 a*. A specimen, natural size. 5 6*. Magnified portion of the cardinal line and visceral impression. 



5 c*. Several striae enlarged, showing the bifid and trifid character. 



Fig. 6. 186. 19. Atrypa increbescens. (Pag. 289.) 



Fig. 7. 343. 5. Oebicula? subteuncata. (Pag. 290.) 



7 a. A small fragment with several individuals upon the surface. 7 S. A single specimen enlarged. 



Fig. 8o. 344. 6. Oebicula? ceassa. (Pag. 290.) 



Fig. 9. 345. 7. Oebicula cjelata. (Pag. 290.) 



9 a. An imperfect specimen. '.> b. The same enlarged, to show the central depression and lateral plications. 

 9 c. A portion of the surface still farther enlarged, showing the character and arrangement of the papillae. 



