290 EVOLUTION AND ANIMAL LIFE 



found in the stone. As Lyell has graphically shown, it took 

 one hundred and fifty years of dispute and argument to persuade 

 even learned men that shells and teeth in the rocks were actual 

 remains of actual animals, and another hundred and fifty j r ears 

 to demonstrate that the shell-bearing rocks were not masses 

 of debris from Noah's flood. Nothing in the history of science 

 is more tedious than the arguments directed against the first 

 students of fossils, to show that these structures were mere 

 sports of nature, whimsicalities of creation, or freaks developed 

 in the fatty matter (materia pinguis) of the earth by the en- 

 tangling influence of the revolving stars. 



Notwithstanding all these defects in material, and this 

 stupidity of theory, the study of fossils has still gone on, and 

 by its means we are able to delineate with large certainty the 

 line of evolution of most groups of animals, and the nature of 

 faunal relations in the different periods of geological time. 

 If we had not already a theory of evolution by derivation of 

 forms, we should be obliged to invent one in face of the facts of 

 paleontology. In Huxley's words, "fossils are only animals 

 and plants which have been dead rather longer than those 

 which died yesterday." 



Fossils are either actual remains of bones or other parts 

 preserved intact in soil or rocks, or else, and more commonly, 

 parts of the animals which have been turned into stone, or of 

 which stony casts have been made. All such remains buried 

 by natural causes are called fossils. The process by which 

 they are sometimes changed from animal substance into stone 

 is called petrifaction. 



Fossils may be of three kinds. In the case of recently 

 extinct animals, bones or other parts of the body may become 

 buried in the .soil and lie there for a long time without any 

 change of organic into inorganic matter. Thus fossil insects 

 are found with the bodies preserved intact in amber, a fossil 

 resin from some ancient and extinct pine tree. Over eight 

 hundred species of extinct insects are known from amber 

 fossils. The bones of the earliest members of the elephant 

 family, the teeth of extinct sharks, the shells of extinct mollusks 

 and fragments of buried logs, are also often found intact, still 

 composed of their original matter. 



In the second kind of fossils the original or organic matter 

 is gone, the organic form and organic structure being preserved 



