334 THE CHANGING GENERATIONS 



which formerly existed have since completely disappeared. Today this 

 idea of extinction is so familiar that we can hardly imagine how strange 

 and revolutionary it then seemed. 



At about this time many people realized that the occurrence of extinct 

 types of fossil animals in the rocks need not conflict with but might 

 actually support the Biblical account, if it were assumed that they were 

 the remains of those killed by the Noachian deluge and buried in its 

 sediments. Soon, however, it developed that each great rock formation 

 had types of fossils that did not occur in the layers above and below it. 

 Furthermore, there began to be much evidence that the earth had been 

 in existence considerably longer than a few thousand years. Confronted 

 by these difficulties, the adherents of special creation advanced the theory 

 of catastrophism — the idea that there had been a succession of great 

 catastrophes, in which all the life of the time was destroyed by flood 

 or fire, followed each time by a new creation of other and higher types. 

 According to this hypothesis the creation recorded in Genesis was the 

 culmination of a series of such acts, and the Noachian deluge was the last 

 of the great catastrophes. Unfortunately for this view, a new interpreta- 

 tion of earth history was shortly to appear and sweep away the assump- 

 tions upon which the whole concept was based. 



The establishment of the uniformitarian principle. While the leading 

 geologists of the time were still engaged in heated debate concerning 

 the nature of the catastrophes supposed to have overwhelmed the earth 

 at intervals, there occurred an epoch-making event in the history of 

 science. This was the appearance of a paper entitled "Theory of the 

 Earth," presented in 1785 to the Royal Society of Edinburgh by James 

 Hutton. In later years Hutton expanded and revised this treatise, and 

 it was published as a two-volume work in 1795. It laid the foundation 

 upon which the modern science of geology has been built. 



Like so many of the great amateurs of science, Hutton had been trained 

 in medicine. He was much interested in natural history and for many 

 years devoted a great deal of time to the study of meteorology, min- 

 eralogy, and geology. His observations gradually led him to a new con- 

 cept of earth history, in which catastrophism had no place. 



Where others had seen in rivers merely streams of water which of 

 course flowed in valleys, since these were the lowest parts of the land, 

 Hutton realized that the rivers themselves had made their valleys by 

 cutting down their beds and by carrying away the weathered rock washed 

 down the valley sides by rain. In place of the accepted idea that the rock 

 strata represented the deposits left by universal floods, Hutton's con- 

 clusion was that they were the weathered products of the land, eroded 

 away and carried into former seas by former rivers. They had been laid 

 down on the sea floor in the same way that muds and sands were being 



