1864.] 



DUNCAN AND WALL JAMAICA. 



in course of formation from the fragments of the pre-existing rocks ; 

 shales and sands, with few organic remains, were deposited on the 

 conglomerate, which in its turn was subject to disturbance and 

 metamorphism. The violence of these phenomena appears to have 

 subsided when the Miocene sands and shales were deposited, neverthe- 

 less they are represented in the occasionally vertical condition of the 

 strata. The great White Limestone suffered from granitic intrusions, 

 and from the final series of movements which affected the whole of 

 the sedimentary rocks and gave the island its present outUne. 



3. List of the Species. 



I. Lower Cretaceous 



1. Diploria crassolamellosa, Edwards 



^ Haime. 



2. Heliastraea exsculpta, Eeiiss, sp. 



3. Heliasti'Eea cyathiformis, spec. nov. 



4. Cyathoseris Haidingeri, Reuss. 



5. Porites Reussiana, spec. nov. 



II. 



6. Paracyathus, sp. 



7. Stylophora contorta, Leymerie, sp. 

 8. , var. nov. 



Eocene, 



9. Stylocoenia emarciata, var., Lamarck, 



sp. 



III. Miocene. 



10. Flabellum exaratum, spec. nov. 



11. Placotrochus costatus, spec. nov. 



12. Placocyathus Moorei, spec, nov, 



13. Trochocyathus obesus, Michelin, 



sp. 



14. Thysanus elegans, spec. nov. 



15. Stylophora granulata, spec. nov. 



16. AntilliaWalli, spec. nov. 



17. Siderastrsea crenulata, var., Blain- 



ville, sp. 



The following species have been already described from the Mio- 

 cene strata, but are mentioned to complete the fauna as at present 

 known * : — 



18. Placocyathus Barretti, Dune. 



19. Placotrochus alveolus, Dune. 



20. Trochocyathus profundus, Dune. 



21. Thysanus excentricus, Dune. 



22. Astroccenia decaphylla, Edwards 



(§■ Haime. 



23. Siderastrsea grandis. Dune. 



24. Cyphastrjea costata. Dune. 



25. Antillia ponderosa, Edwards ^ 



Haime, sp. 



26. Alveopora Dadalsea, var. regularis, 



Blainville, sp. 



27. Trochocyathus abnormalis, Dune. 



(doubtfiU). 



4. Descriptions and Notices of the Species. 

 1. Diploria crassolamellosa, Edwards & Haime. 



Localities: Trout Hall and Upper Clarendon, Jamaica; Gosau, 

 Europe. 



usually much silicified, and in some instances a considerable extent of serpentine 

 is developed, which almost invariably retains some evidences of stratification. 



A true foliated schistose structure is never presented ; but there are some in- 

 stances of shales and calcareous slates vrhich, when near the eruptive centre, 

 manifest a tendency to the arrangement of separate minerals in parallel layers ; 

 but in the most advanced degree it only amounts to an incipient stage of that 

 fohated condition characterizing true crystaUine schists, such as mica-slate and 

 gneiss. * P. M. Duncan, op. cit. 



