§ 3. HARMONY WITH REVELATION. 27 



the exception of the effects of a general deluge, its surface 

 has undergone no material change, many of the facts to be 

 noticed in the course of these lectures may appear almost 

 incredible, and the inferences drawn from their investi£a- 

 tion be regarded as the vagaries of the imagination, rather 

 than as the legitimate deductions of sound philosophy. If, 

 therefore, it be absolutely necessary, as it unquestionably 

 is, that in the pursuit of knowledge of any kind, before 

 even experience can be employed with advantage, we must 

 dismiss from our minds all prejudices, from whatsoever 

 source they may arise, this mental purification becomes the 

 more indispensable in a science like Geology, in which 

 we meet at the very threshold with facts so novel and 

 astounding ; facts which prove, that though man and other 

 living things be, as it were, but the creation of yesterday, 

 the earth has teemed with numberless forms of animal 

 and vegetable life, myriads of ages ere the existence of the 

 human race. 



Geology may be termed the physical history of the 

 earth, — it comprehends the investigation of the mineral 

 structure of our globe, and the characters and causes of 

 the various changes which have taken place in the organic 

 and inorganic kingdoms of nature. It has been empha- 

 tically denominated by one of our most distinguished philo- 

 sophers, the sister science of Astronomy. But, relating as 

 it does to the history of the past, and carrying us back by 

 the careful examination of the relics of former ages, to 

 periods so remote as to startle all our preconceived opinions 

 of the age of our planet, the fate of its early cultivators has 

 resembled that of the immortal Galileo and the astronomers 

 of his times ; and for a similar reason, namely, the supposed 

 discrepancy between the discoveries and inferences of this 

 science, and the Mosaic cosmogony. 



3. Harmony between revelation and geology'. — 

 There was a time when every geologist was compelled to 



