XVI 



LIST OF ILLUSTRATIONS. 



48. Ptilodictya falciformis 109 



49. Ptilodictya S chaff eri. . 109 



50. Group of Lower Silu- 



rian Brachiopods. . . . no 



51. Group of Lower Silu- 



rian Brachiopods... in 



52. Murchisonia gracilis... 112 



53. Bellerophon argo 113 



54. Maclurea crenulata... 113 



55. Orthoceras crebrisep- 



tum 114 



56. Restoration of Ortho- 



ceras 114 



57. Generalized section of 



the Upper Silurian 

 rocks 119 



58. Monograptus priodon.. 121 



59. Halysites catenularia 



and H. agglomerata 122 



60. Group of Upper Silu- 



rian Star-fishes 123 



61. Protaster Sedgwickii.. 123 



62. Group of Upper Silu- 



rian Crinoids 124 



63. Planolites vulgaris.... 125 



64. Group of Upper Silu- 



rian Trilobites 126 



65. Pterygotus Anglicus... 127 



66. Group of Upper Silu- 



rian Polyzoa 128 



67. Spirifera hyst erica 128 



68. Group of Upper Silu- 



rian Brachiopods 129 



69. Group of Upper Silu- 



rian Brachiopods.... 129 



70. Pentamerus Knightii. . 130 



71. Cardiola interrupta, C. 



fibrosa, and Pterinaa 

 subfalcata 130 



72. Group of Upper Silu- 



rian Univalves 131 



73. Tentaculites ornatus... 131 



74. Pteraspis Banksii 132 



75. Onchus tenuistriatus 



and Thelodus 132 



76. Generalized section of 



the Devonian rocks 



of North America. . . 139 



77. Psilophyton prince ps. . 140 



78. Prototaxites Logani. . . 141 



79. Stromatopora tubercu- 



lata 142 



80. Cystiphyllum vesiculo- 



sum ................ 143 



81. Zaphrentis cornicula. 143 



82. Heliophyllum exiguum 143 



83. Crepidophyllum Archi- 



aci. . . . ............. 144 



84. Favorsites Gothlandica 145 



85. Favo sites hemisph&r- 



ica .................. 145 



86. Spirorbis omphalodes 



and S. Arkonensis. . . 146 

 Spirorbis laxus and s. 



spinulifera .......... 146 



Group of Devonian 



Trilobites 



87. 

 88. 

 89. Wing of Platephem- 



147 



147. 



era antiqua .......... 



90. Clathropora intertexta 148 



91. Ceriopora Hamilton- 



ensis ................ 148 



92. Fenestella magnifica.. 148 



93. Retepora Phillip si ____ 148 



94. Fenestella cribrosa... 148 



95. Spirifera sculptilis . . . 149 



96. Spirifera mucronata 149 



97. Atrypa reticularis. ... 150 



98. Strophomena rhom- 



boidalis ............. 150 



99. Platyceras dumosium 151 



100. Conularia ornata ..... 151 



101. Clymenia Sedwickii. . 152 



102. Group of Fishes from 



the Devonian rocks 



of North America.. 154 



103. Cephalaspis Lyellii. . . 155 



104. Pterichthys cornutus 156 



105. Polypterus and Osteo- 



lepis ................ 157 



1 06. Holoptychius nobilis- 



simus. .............. 158 



107. Generalized section of 

 ' the Carboniferous 



rocks of the North 



of England ......... 164 



108. Odontopteris Schloth- 



eimii ............... 168 



109. Catamites cannafor- 



mis ................. 169 



no. Lepidodendron Stern- 



bergii ............... 171 



1 1 r. Sigillaria Gr&seri ..... 172 



112. Stigmaria ficoides ---- 173 



