Fig. 



* 









1. 



Estheria 



membranacea 



(P- 



14) 



2. 



» 



>t 







3. 



>i 



» 







4. 



y> 



>> 







PLATE I. 



— A group on sandy flagstone, nat. size. Caithness. 

 A pair of valves, open, and somewhat displaced ; their dorsal edges 



approximate ; the ridges lost in wrinkles : x 4 diam. Caithness. 

 A single valve (right) : X 4 diam. Caithness. 

 Outline of the same valve, X 6 diam., for comparison with other 



Estherice magnified 6 times. Caithness. 



5. ,, „ The surface between two ridges, x 100 diam. Probably showing the 



effects of sand-grains interfering with the natural ornament. 

 Caithness. 



6. ,, „ Left valve, well preserved, from Kokenhusen, Livonia: x G diam. 



7. „ ,, Ornament of an interspace of the same: X 100 diam. 



8. Estheria striata, var. Binneyana (p. 28). — From near Chesterfield, Derbyshire; outline of valve: 



X 6 diam. 



9. ,, ,, „ A pair of displaced valves ; nat. size. Near Chesterfield. 



10. „ „ ,, Portion of the surface : x 50 diam. Chesterfield. 



11. Estheria striata, var. Beinertiana (p. 25). — Right valve from Shaly Brow, Lancashire: X 6 diam. 



12. „ „ „ Portion of the surface of the same, showing the nearly 



smooth outside, and the wrinkled interior : x 50 diam. 



13. „ ,, ,, Left valve; from Silesia: x 6 diam. 



14. „ ,, ,, Portion of the surface of the same: X 50 diam. 



15. Estheria striata, var. Tateana (p. 26). — Right valve; Lammerton, Berwickshire: x 6 diam. 

 16,17. ,, ,. Cellular structure, remaining in the shale; Lammerton: 



X 75 diam. 



18. „ „ „ Left valve of a shorter individual ; Lammerton: x 6 diam. 



[A still shorter form is shown in the woodcut at p. 26.] 



19. Leaia Leidyi, var. Williamsoniana (p. 117). — The inside view of two conjoined valves; Ardwick, 



Manchester: x 6 diam. 



20. „ „ „ Right valve, outside ; Ardwick : x 6 diam. 



21. Leaia Leidyi, var. Salteriana (p. 119). — Outline of left valve; Fifeshire : x 6 diam. 



22. Estheria exigua (p. 37). — Right valve. (Probably young.) Kargala, Russia : x 6 diam. 



23. „ „ The same valve : x 20 diam. 



24. „ „ Portion of the surface : X 100 diam. 



25. Estheria Portlockii (p. 40). — Hollow mould of right valve; Rhone Hill, Tyrone : x 6 diam. 



26. Estheria tenella (p. 31). — Right valve ; Oschatz, Saxony: X 6 diam. 



27. „ „ Portion of the surface of the same : x 75 diam. 



28. Estheria minuta (p. 42). — Right valve, its ridges lost in wrinkles ; Sinsheim : X 6 diam. 



29. „ ,, Left valve of a larger and better preserved specimen ; Sinsheim: X 6 diam. 



30. ,, „ Portion of the surface of another specimen, showing the reticulated inter- 



space between the ridges : x 75 diam. 



31. 32. Inoceramus (Posidonomya) Suessii, Oppel (p. 12). — From the bluish shale of the Lower Oolite 



(zone of Ammonites torulosus), Kandern, 

 Baden ; for comparison with Estheria 

 minuta. Fig. 31, portion of a valve, and 

 mould of a part of another : x 6 diam. 

 Fig. 32, portion of the surface : x 75 

 diam. (This shell occurs also in the 

 Oxford Clay near Peterborough.) 



