viii List of Illustrations in the Text. 



PAGE 



North bank of the Great Rangit Valley ...... 405 



Five segments from the cast of Palceosoma giganteum .... 407 



Reconstructed posterior segments of Palceosoma giganteum . . . 408 



Palceosoma robusfum ......... 409 



Development of major septa in a normal Rugose Coral . . . 436 



Analysis of interambulacral tuberculation in Pyrina and Conulus . . 445 



Iceland, after Th. Thoroddsen 468 



Diagrammatic section across the Bryozoa Reef ..... 486 



Curve showing number of invertebrate species, Durham Permian . . 488 



Diagrammatic section across the Permian outcrop .... 489 



Diagram to illustrate structure of Rock and Spindle shore stack . 502 



Four diagrams to illustrate the occurrence, proportions, and distribution 



of silica in Chalk 538-44 



