84. Termination of a scale of ditto 82 85. Section of a scale of ditto 82 86. The Dirt-bed of the island of Portland 83 87. Cycadoidea megalophylla (Mantellia nidiformis of Brongniart) 83 88. Kaidacarpum ooliticum (Carr.) 84 89. Pandanus odoratissimus 84 90. Fossil wood, Abietites Linkii 85 91. Sequoiites ovalis 88 92. Pinites ovatus (Zamia ovata of Lindley and Hutton) 89 93. Palmacites Lamanonis 90 95. Comptonia acutiloba 92 96. Acer trilobatum 93 97. Ulmus Bronnii 93 98. Rhamnus Aizoon 94 99. Alnus gracilis 95 100. Taxites or Taxodites Campbellii 95 101. Rhamnites multinervatus 95 102. Equisetum Campbellii 96 PALÆONTOLOGICAL BOTANY. The study of the changes which have taken place in the nature of living beings since their first appearance on the globe till the period when the surface of the earth, having assumed its present form, has been covered by the creation which now occupies it, constitutes one of the most important departments in Geology. It is, as Brongniart remarks, the history of life and its metamorphoses. The researches of geologists show clearly that the globe has undergone various alterations since that "beginning" when "God created the heavens and the earth." These alterations are exhibited in the different stratified rocks which form the outer crust of the earth, and which were chiefly sedimentary deposits produced by the weathering of the exposed rocks. Remains of the plants and animals living on the globe at the time of the formation of the different beds are preserved in them. Elevations and depressions of the surface of the earth affected the organisms on its surface, and gave to successive deposits new faunas and floras. Some of these epochs have been marked by great changes in the physical state of our planet, and they have been accompanied with equally great modifications in the nature of the living beings which inhabited it. The study of the fossil remains of animals is called Palæozoology (παλαιός, ancient, and ζῷον, animal), while the consideration of those of vegetables is denominated Palæophytology (παλαιός and φυτόν, a plant). Both are departments of the science of Palæontology, which has been the means of bringing geology to its present state of advancement.