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. agglomerate, 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 hysterica 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. 



81. 

 82. 

 83. 



84. 

 85. 



86. 

 87. 

 88. 

 89. 



90. 

 91. 



92. 

 93. 

 94. 

 95. 

 96. 

 97. 

 98. 



99. 

 100. 

 101. 

 102. 



103. 

 104. 

 105. 



106. 

 107. 



108. 

 109. 

 no. 



in. 

 112. 



Cystiphyllum vesiculo- 



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



Zaphrentis cornicula. 143 

 Heliophyllum exiguum 143 

 Crepidophyllum Archi- 



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



Favorsites Gothlandica 145 

 Favo sites hemisphar- 



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



Spirorbis omphalodes 



and . Arkonensis. . . 146 

 Spirorbis laxus and s. 



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



Group of Devonian 



Trilobites .......... 147 



Wing of Plat ephem- 



era antiqua .......... 147. 



Clathropora intertexta 148 

 Ceriopora Hamilton- 



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



Fenestella magnifica,. 148 

 Retepora Phillipsi ____ 148 



Fenestella cribrosa... 148 

 Spirifera sculptilis . . . 149 

 Spirifera mucronata 149 

 Atrypa reticularis ---- 150 



Strophomena rhom- 



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



Platyceras dumosium 151 

 Conularia ornata ..... 151 



Clymenia Sedwickii.. 152 

 Group of Fishes from 



the Devonian rocks 



of North America. . 154 

 Cephalaspis Lyellii... 155 

 Pterichthys cornutus 156 

 Polypterus and Osteo- 



eps ..... ........ ... 157 



Holoptychius nobilis- 



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



Generalized section of 

 ' the Carboniferous 



rocks of the North 



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



Odontopteris Schloth- 



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



Calamites cannafor- 



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



Lepidodendron Stern- 



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



Sigillaria Groeseri ..... 1 72 



Stigmaria ficoides ---- 173 



