CHAPTER XXXVII 

 PALEOBOTANY 



503. The Scope of Paleobotany. — The study of fossil 

 plants, though of course a phase of botany, constitutes 

 a science by itself, not only covering a special subject 

 matter, but having its own methods (technique), and pos- 

 sessing a large literature. It is called paleobotany. One 

 cannot pursue this study without a knowledge of the 

 anatomy and morphology of living forms. This is neces- 

 sary in order to interpret the meaning of plant fossils, 

 which often occur only in small fragments of the entire 

 plant. Moreover, one must have a good knowledge of 

 at least the elements of geology, since fossils are found in 

 rocks. One must not only know the geological age to 

 which the fossil-bearing rock he studies belongs, but also 

 something of the geological processes by which fossils, 

 and even the rocks themselves, are formed. 



504. What is a Fossil? — A fossil is any remains of a 

 plant or animal that lived in a geological age preceding 

 the present; these remains are preserved in rocks. ^ There 

 are two methods of preservation, namely, incrustation and 

 petrifaction. Incrustations are merely impressions or 

 casts resulting from the encasement of the organ or 

 organism in the rock-forming material. The tissue itself 



^ By an extension of the term we also speak of fossil footprints of ani- 

 mals, fossil ripple marks, et cetera. The word fossil is derived from the 

 LzX\nfodere (to dig), and originally signified anything dug up. 



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