XX 



CONTENTS. 



CHAPTER XLVI. 



SHELLS OF THE LOWER SILURIAN ROCKS. 



Page 



Shells of the Caradoc Formation, Pis. 19, 20, 21.— Shells of the Llandeilo Flags, PL 22 634 



CHAPTER XLVII. 



TRILOBITES OF THE SILURIAN SYSTEM. 



General view of Trilobites. — Their geological range. — Trilobites of the Ludlow and Wenlock Formations, 

 or Upper Silurian Rocks, PL 7, 7 bis, 14. — Trilobites of the Caradoc and Llandeilo Formations, 

 or Lower Silurian Rocks, Pis. 23, 24, 25. — Structure and Affinities of Trilobites 645 



CHAPTER XLVIII. 



ENCRINITES AND ZOOPHYTES OF THE SILURIAN SYSTEM. 



Crinoidea, PI. 17 and 18. — Polyparia, PI. 15, 15 bis, 16, 16 bis. — Other Zoophytes and nondescripts, 



PI. 26.— Annelida of the Upper Cambrian Rocks, PL 27 670 



Tabular List of Organic Remains 703 



Description of Coloured Sections > . . 703 



Appendix 726 



Index • • • • • 735 



Organic Remains, Plates 1 to 27. 



Coloured Sections, Plates 29 to 37. 



