THE PROGRESS OF GEOLOGY 



i 



PREPOSSESSIONS IN REGARD TO THE DURATION OF PAST TIME 

 PREJUDICES ARISING FROM OUR PECULIAR POSITION 

 AS INHABITANTS OF THE LAND OTHERS OCCASIONED BY 

 OUR NOT SEEING SUBTERRANEAN CHANGES NOW IN PROG- 

 RESS ALL THESE CAUSES COMBINE TO MAKE THE FORMER 

 COURSE OF NATURE APPEAR DIFFERENT FROM THE PRES- 

 ENT OBJECTIONS TO THE DOCTRINE THAT CAUSES SIMI- 

 LAR IN KIND AND ENERGY TO THOSE NOW ACTING, HAVE 

 PRODUCED THE FORMER CHANGES OF THE EARTH'S SUR- 

 FACE CONSIDERED 



IF WE reflect on the history pf the progress of geology 

 * * * we perceive that there have been great fluctuations 

 of opinion respecting the nature of the causes to which 

 all former changes of the earth's surface are referable. The 

 first observers conceived the monuments which the geologist 

 endeavours to decipher to relate to an original state of the 

 earth, or to a period when there were causes in activity, 

 distinct, in a kind and degree, from those now constituting 

 the economy of nature. These views were gradually modi- 

 fied, and some of them entirely abandoned, in proportion 

 as observations were multiplied, and the signs of former 

 mutations were skilfully interpreted. Many appearances, 

 which had for a long time been regarded as indicating 

 mysterious and extraordinary agency, were finally recognised 

 as the necessary result of the laws now governing the 

 material world; and the discovery of this unlooked-for con- 

 formity has at length induced some philosophers to infer, 

 that, during the ages contemplated in geology, there has 

 never been any interruption to the agency of the same uni- 



1 The text of the two following papers is taken from the nth edition 

 of Lyell's Principles of Geology, the last edition revised by the author. 



405 



