LECTURE VIII. 



Part I. — The Devonian, Silurian, ahd Cumbrian Formations. 



1. Introductory. 2. The Devonian System. 3. Subdivisions of the Devonian 

 System. 4. Devonian Strata of Devonshire and Cornwall. 5. Devonian Strata of 

 Scotland. 6. Devonian System of the Continent and America. 7. Organic 

 Remains of the Devonian System. S. Crustaceans of the Devonian. 9. Fishes 

 of the Devonian. 10. The Silurian System. 11. Subdivisions of the Silurian 

 System. 12. Silurian System of England 13. Silurian Strata of Staffordshire. 

 14. The Clent Hills. 15. The Wrekin. 16. The Malvern Hills. 17. Silurian 

 Strata of Europe and America. IS. Fossils of the Silurian System. 19. Silurian 

 Zoophytes and Molluscd. 20. Silurian Gasteropoda and Cephalopoda. 21. Silu- 

 rian Annelides and Crustaceans. 22. Visual Organs of the Triiobites. 23. Fishes 

 of the Silurian System. 24. The Cumbrian or Schistose System. 25. Structure 

 of Slate Rocks. 26. Slate Rocks of Shropshire and Cumberland. 27. Review of 

 the Silurian and Cumbrian Systems. 



1. Introductory. — In the previous Lecture the Floras of 

 the palaeozoic ages constituted the principal subject of inves- 

 tigation. \Te examined the primeval forests of coniferce. 

 and the groves of palms and arborescent ferns, which clothed 

 the surface of the soil in that remote period of the earth's 

 physical history. The insects which fluttered among the 

 tropical vegetation of the islands and continents of those 

 ancient epochs, and the fishes and crustaceans which inha- 

 bited the seas and rivers, were brought in review before us. 

 and we contemplated their extraordinary forms and organi- 

 zation, as preserved by those natural processes, 



'• Which turned the ocean-bed to rock, 

 And changed its myriad living swarms 



To the marble's veined forms." 



.MF.5, H-^Iir, 



