CONTENTS. Xt 



tions of environment in relation to time estimates Relative order of 

 deposits in relation to depression and elevation, 73. Order of deposits 

 with a sinking land Order of deposits with elevation of land, 74. 

 Characteristic fossils, 75. Summary, 76. 



CHAPTER V. 



FOSSILS THEIR NATURE AND INTERPRETATION, AND THE GEOLOGI- 

 CAL RANGE OF ORGANISMS. 



Fossils of vegetable and animal origin Original material of fossils, 78. 

 Various aspects of the original form represented Preservation of fos- 

 sils, 79. The majority of fossils are of marine organisms Various 

 kinds of fossils enumerated, 80. Fossils represent chiefly the hard 

 parts of organisms Best and most perfectly adjusted organisms of 

 the time left their records General laws regarding the occurrence of 

 fossils, 81. Change of the forms with passage of time, and particu- 

 lar forms characteristic of particular periods of time, undeniable facts 

 of Paleontology Inorganic things, on the contrary, unchangeable 

 Fossils characteristic of particular periods of geologic time, 83. Stony 

 corals, the Zoantharia Numbers of genera of the Zoantharia recorded 

 for each era, 84. Two types of the Zoantharia indicated by the two 

 maxima of genera in separate eras in the time-scale Table of the 

 number of genera of Madreporaria making their first appearance in 

 each geological system, grouped in families Evolution curve of a 

 group of organisms, 85. Evolution curves of the various types of the 

 Madreporaria, expressing the rate of generic differentiation of each 

 type Meaning of these evolution curves, 87. Chronological value of 

 family groups of genera The life-period of a genus, 88. Organisms 

 express evolution in their geological history; a fundamental law The 

 meaning of genus and species, 89. The fossil coral, Favosites niaga- 

 rensis, as an illustration, 90. Geological range and taxonomic ranks 

 of the characters, 92. Table expressing the geological range of the 

 characters of the fossil Favosites niagarensis Hall, arranged according 

 to their taxonomic rank Time-values of the characters of an individ- 

 ual differ according to their taxonomic rank, 93. Stages of growth in 

 Ontogenesis, 94. No successive stages of functional activity seen in 

 Phylogenesis Contrast between the developmental stages of the in- 

 dividual and the succession of species, 95. Evolution an organic pro- 

 cess, and not applicable to inorganic things Fossils furnish the direct 

 evidence of evolution, 96. Living organisms furnish direct evidence 

 of purposeful development, 97. Fossils and geological biology Hard 

 parts express both relation to environment and relation to ancestry, 

 98. Kinds of hard parts of the animal kingdom preserved as fossils 

 Protozoa, 99. Ccelenterata, 100. Echinodermata Vermes Arthrop- 

 oda, 101 Molluscoidea, 104. Mollusca, 105. Vertebrata, 106. 

 Summary, 109. 



CHAPTER VI. 



GEOGRAPHICAL DISTRIBUTION THE GENERAL RELATION OF ORGANISMS 

 TO THE CONDITIONS OF ENVIRONMENT. 



The importance of the study of geographical distribution, 112. The nat- 

 ural conditions of environment : nomenclature Natural-history prov- 



