FOSSILS AND THEIR STORY 



1087 



FAVOSITES—A FOSSIL CORAL FROM THE 

 UPPER SILURIAN. 



has been formed, and it will help us to a 

 fuller appreciation of those vast changes, 

 climatic and geographical, through which 

 the earth has passed. 



In " Cliffs and their Story," " Sand 

 Dunes," and " Nature's Masonry " we 

 have gained some insight into the methods 

 which Nature employs in sculpturing and 

 moulding the face of the earth. Now let 

 us turn our attention to the fossils which 

 we shall find imbedded in the rocks of 

 the different formations, and try to piece 

 together the wonderful history of the past. 

 In most of the sedimentary rocks, fossil 

 remains, usually 

 consisting of 

 bones, shells, teeth 

 of animals and the 

 remains of plants, 

 are to be found, 

 and with their aid 

 it is possible to 

 reconstruct the 

 creatures and 

 plants that were 

 peculiar to the for- 

 mation in which 

 they are found. 



Casually glanc- 

 ing over a large 

 collection of fos- 

 sils, we cannot 

 help noticing that 

 many have a more 

 or less distinct 

 likeness to some 

 of the animals and 

 plants that are 



still in existence ; but examples of exact 

 resemblance are confined chiefly to the 

 newer deposits, and even here are com- 

 paratively rare. 



It is very interesting to observe how, 

 in the struggle for existence, it is the 

 simpler forms of life which have persisted 

 with comparatively little change through 

 past geological ages, while the more 

 complex forms of life have either become 

 totally extinct, or have undergone con- 

 siderable modification ; while a closer 

 examination of these fossils will demon- 

 strate and deeply impress the circum- 

 stantial truth of Darwin's theory of 

 Evolution. Nor must we forget that it 

 is by the careful examination and com- 

 parison of fossil remains that the biologist 

 has been enabled to determine the ancestry 

 and evolution of many forms of life to be 

 met with to-day. 



It is impossible, in dealing with the 

 history of the earth, to give any numerical 

 idea of the passage of the ages, and 

 therefore it becomes necessary to divide 

 geological time into periods or formations. 

 These periods have been definitely fixed 

 by the character of the rocks and the fossil 

 remains peculiar to each, and may be 

 divided into three great eras. These 

 three great eras have been given names 

 of Greek origin : the first has been named 



NKURUI'TKKIS-A FOSSIL FERN FROM THE COAL 



