INTRODUCTORY CHAPTER. 



621 



world at far distant epochs of time, and the various forms of organic life that were 

 coincident with them, with the action of mighty forces that have repeatedly changed its 

 surface, sweeping numerous tribes of plants and animals from the catalogue of the earth's 

 inhabitants, and involving them in the oblivion of ages, till the discovery of their remains 

 in the fossiliferous rocks. " We learn," says Sedgewick, " that the manifestations of God's 

 power on the earth have not been limited to the few thousand years of man's existence. 

 The geologist tells us, by the clearest interpretation of the phenomena which his labours 

 have brought to light, that our globe has been subject to vast physical revolutions. He 

 counts his time, not by celestial cycles, but by an index he has found in the solid frame- 

 work of the globe itself. He sees a long succession of monuments, each of which may have 

 required a thousand ages for its elaboration. He arranges them in chronological order, 

 observes in them the marks of skill and wisdom, and finds within them the tombs of the 

 ancient inhabitants of the earth. He finds strange and unlooked-for changes in the forms 

 and fashions of organic life, during each of the long periods he thus contemplates. He 

 traces these changes backwards, through each successive era, till he reaches a time when 

 the monuments lose all symmetry, and the types of organic life are no longer seen. He 

 has then entered on the dark age of Nature's history ; and he closes the old chapter of 

 her records." These are revelations calculated to stimulate intellectual action, and to 

 apply a wholesome discipline to the mind, while expanding it by an obvious moral 

 lesson. However the phenomena in detail may be interpreted, there can be no question 

 about the general explanation ; and clear enough is the fact, that through the revo- 

 lution of centuries mankind were completely in the dark respecting both the mechanism 

 of the heavens and the economy of the earth. Even now, though the threshold of the 

 temple of knowledge has been passed, how little can man explain the realities that have 

 dawned upon his apprehension ! Both facts give an impressive rebuke to human into- 

 lerance and pride ; and especially teach us to avoid an air of censoriousness towards those 

 who differ from us in judgment, because of the manifest fallibility of the nature which we 

 inherit. 



Granite Rocks of Metcora. 



