IX. 



RH^TIC FOSSILS. 



107 



To trace the progress of this newer life through the true lias and 

 oolites is one of the most interesting problems of Palaeontology. 

 It is deserving of remark that the shells are generally small, almost 

 dwarfish. But for the difference of size, we should find it not easy 

 to separate the Myacites and Modiolse, and even the Aviculae (called 

 Monotis), from species which occur in the lias beds considerably 

 above these which are so closely allied to the rha3tics. 



REFERENCE TO PLATE VII, CONTAINING FOSSILS OF THE 

 RILETIC AND LOWER LIAS STRATA. 



IN THE BONE-BED SERIES. 



West- 



1. Cardium cloacinum. Querist. 



bury. 



2. Cardium rhaeticum. Merian. 



Philippianum Quenst.) 



3. Avicula contorta. Portlock. 



villia striocurva. Quenst.) 



4. side view. 



5. Discina Townsendi. Uphill. 



6. 7, 8, 9, 10. Specimens usually re- 



gard. 

 (Ger- 



ferred to Pullastra arenicola of 

 Strickland. 



II, 12. Interior, shewing the hinge of 

 opposite valves. 



13. Pleurophorus elongatus. Moore. 



14. Pecten Valoniensis. 



15. Scale of Gyrolepis tenuistriatus. Ag. 



16. Tooth of Saurichthys apicalis. Ag. 



17. Tooth of Hybodus plicatilis. Ag. 



FROM THE ESTHERIA BED. 



1 8. Estheria minuta. 



19. Magnified view of the surface. 



20. Parts of an umbellate plant. Buck. 



21. Equisetum Brodiaei. Buck. 

 12. Naiadita lanceolata. Brod. 

 23. Naiadita obtusa. Buck. 



24. Naiadita petiolata. Buck. 



25. Leaf of a plant compared to one of 



the Ericaceae. Buck. 



26. Cupresaus ? latifolia. Buck. Prob- 



ably a Thuytes or Brachyphyllum. 



27. Hippurites ? Buck. 



FROM THE LOWEST 



28* LibeUula Hopei. Brodie. Strens- 

 ham. 



29. Gryllus Bucklandi. Brodie. Graf ton. 



30. Orthophlebia communis. Westwood. 



Wainlode. 



31. Chauliodes sp. Bidford. 



32. Elytra of Dyticus ? Brodie. Wain- 



lode. 



* 3*. Buprestis. Brodie. Wainlode. 



32 Wing of neuropterous insect. Wain- 

 lode. 

 35. Elytra of Berosus. Westbury. 



36. 



37- 

 38. 

 39 



46 



47 



49 



LIAS BEDS. 

 Myacites musculoides (dwarfed). Geol. 



Surv. Westbury. 

 Modiola minima. Goldf. Westbury. 



Do. do. do. 



to 45. Avicula decussata (Monotis, 



Goldf.) Right and left valves. 

 . Young Ostrea liassica. Westbury. 

 . Ostrea liassica, young. Westbury. 

 . Tooth of Cidaris Edwardsii. Wright. 



Westbury. 



. Spine of Cidaris Edwardsii. Wright. 

 Westbury. 



* The figures of insects 28-34 are from tte valuable volume on Fossil Insects by 

 the Rev. P. B. Brodie, F.G.S. 



