( 222 ) 



XXIV. 



How SPECIES PERISH. 



As the planet Earth has gone cycling on in glorious 

 grandeur age after age, from the very earliest dawn of 

 life upon its surface, the various organisms with which it 

 has been peopled have undergone many more or less 

 mighty changes. Species, like individuals, are born and 

 die. The noble science of geology enables us to read 

 the chequered history of those earlier forms of life which 

 have left the record of their being behind them indelibly 

 stamped upon the rocks and otherwise imbedded in the 

 crust of the earth. From these records, blurred, im- 

 perfect and often nearly illegible though they be, we 

 learn that each geological period had its peculiar fauna 

 and flora vast numbers of species lived and flourished 

 in those far-off ages, very distinct from any existing 

 forms of life. Where are all those old-time species now ? 

 The grand process of Evolution, by means of Natural 

 Selection and other important agencies, has been con- 

 stantly at work developing new species from these 

 ancient forms, better adapted to live under the ever- 

 changing conditions an ever-changing universe is im- 



