Fig. 66. BARREN ISLAND IN THE BAY f)F BENGAL. 



THE CRUST OF THE EARTH; 



OR, FIRST NOTIONS OF GEOLOGY. 



CHAPTEE III. 



. Spondylus. 71. Pentamerus. 72. Reticulipora. 73. Ceratites. 

 74. Enormous masses of animal remains forming entire islands and 

 continents Ehrenberg's discoveries. 75. Dr. Mantell's table of 

 organic strata. 76. Forms of life in the Silurian period. 77. Sir 

 R. Murchison's observations on the changes of the forms of life from 

 period to period. 78. Stratification in undisturbed plains horizontal. 

 79. Strata thrown into oblique positions by disruption of igneous 

 rocks. 80. Formation of mountains. 81. Arrangement of strata 

 on their flanks. 82. Strata sometimes upheaved without being 

 disrupted. 83. Sometimes disrupted. 84. Sedimentary strata de- 

 posited subsequently to disruption discordant stratification. 

 85. How these supply data for determining the epoch of the 

 disruption. 86. Determination of the relative ages of mountains 

 Cumbrians and Grampians much older than the Alps. 87. How 

 inclined strata have enabled geologists to analyse the structure of the 

 terrestrial crust to the level of the igneous rocks. 88. Erosion of 

 stratification by the action of water, and the subsequent deposition 

 of other strata. 89. Basalts their character and composition. 

 90. Various forms of basaltic rocks. 91. Their extensive diffusion 

 over all parts of the earth. 92. Their columnar structure Giant's 

 Causeway. 93. Basaltic causeway of the Volant Dykes and colonnade 

 of Cheuavari. 94. Veins of basalt. 95. Basalts in mounds. 96. 

 Basaltic grottoes Kase grotto of Bertrich-Baden Fingal's Cave. 

 97. Trachytic rocks. 98. Trachytic mountains. 99. Their origin 

 igneous. 



LARDNER'S MUSEUM OF SCIENCE. F 65 



No. 135. 



