LECTURE IV. 



Part I. 



I. Introductory. 2. Formations of the Secondary Epoch. 3. Cretaceous Formation. 

 4. Chalk Downs. 5. Flint nodules and veins. 6. Organic remains in flint. 

 7. Animalcules in flint. 8. Xanthidia. 9. Middle and Lower groups of the 

 cretaceous strata. 10. Folkstone Cliffs. 11. Cretaceous strata of Maastricht. 

 12. The Mosasaurus. 13. Cretaceous deposits of other countries. 14. Organic 

 remains of the Chalk Formation. 15. Fossil vegetables. 16. Zoophytes of the 

 Chalk. 17. Animalculites of the Chalk. 18. Chalk Rotalias. 19. Chalk detritus 

 at Charing. 20. Spirolinites. 21. Crinoidea of the Chalk. 22. Star-fish. 

 23. Echinites. 24. Shells of the Chalk. 25. Cephalopoda. 26. The Nautilus. 

 27. Ammonites 28. Turrilites and Hamites. 29. The Belemnite. 30. Crusta- 

 ceans of the Chalk. 31. Fishes of the Chalk. 32. Scales of Fishes. 33. Teeth of 

 Sharks. 34. Hypsodon and other fishes. 35. Fossil Salmon. 36. The Macropoma. 

 37. Beryx, and other fishes of the Chalk. 38. Reptiles of the Chalk. 39. Fossil 

 Turtles. 40. Summary.— Tabular arrangement of Sussex Chalk fishes. 



1. Introductory. — The knowledge we have acquired 

 from our investigation of the phenomena described in the 

 previous lectures, will materially facilitate our geological 

 progress, by enabling us to comprehend the former effects 

 of those physical agencies, by which the surface of the 

 earth has been perpetually renovated, and maintained in a 

 suitable condition for the existence of successive races of 

 animated beings. 



The elevation of the beds of seas and rivers, and their 

 conversion into fertile countries — the submergence of 

 islands and continents beneath the waters of the ocean — the 

 rapid formation of conglomerates from shells and corals on 

 the sea-shore — the accumulation of beach and gravel, and 



