4 o SCIENCE PROGRESS. 



position of stratified rocks ; none but an impatient mind 

 will feel other than grateful to Plot for having subjected 

 these fundamental principles to the severest examination, 

 for having spared no argument which could possibly be 

 brought against them. Next to suggestive generalisa- 

 tion, Science stands in need of honest criticism. Geology 

 required a prophet, and she found him in Steno, but she 

 also required a critic, and in Plot she met with one of 

 the most penetrating intellect and uncompromising spirit. 



Both sides of this momentous controversy had now been 

 fairly presented to the world, and it was left for the faithful 

 labours of the next century to arrive at a decision. The 

 principles of Steno eventually prevailed, and Geology en- 

 tered upon a new phase of her existence ; she commenced 

 to free herself from the trammels of time ! 



Hutton in his great work The Theory of the Earth, pub- 

 lished in 1788, attacked the subject on that side where 

 Steno had most conspicuously failed. His method was the 

 same as Steno's ; just as Steno had explained fossil remains 

 by comparison with living animals, so Hutton explained the 

 past history of the earth by comparison with the present. 

 If this county of Oxfordshire was, together with all England, 

 at one time submerged fathoms deep beneath the sea, it was 

 owing to a slow movement of subsidence such as Hutton 

 considered was affecting islands and continents at the 

 present day. Would we account for the marine sediments 

 of which our land consists, we have but to turn our eyes to 

 the rivers constantly bearing their burden of mud into the 

 sea, where it is spread abroad in strata precisely similar to 

 those of the remote past. As strata are formed now, so 

 have they always been formed ; as lands rise and fall now, 

 and seas pass imperceptibly into continents, and continents 

 into seas, so they have always done in the past. But how 

 slowly all these changes proceed ! A human lifetime is not 

 long enough to witness any appreciable effect. In this 

 period the thickness of stratified material laid down by a 

 river in the sea would not amount to more than a few 

 inches, and the rocks of the earth's crust are many thousands 



