72 HISTORY OF GEOLOGY AND 1 3 AL/EONTOLOGY. 



of Hutton certainly gave rise to several errors in connection 

 with the origin of minerals and rocks. No geologist now 

 would agree with the principle that heat has hardened and 

 partially melted all sedimentary rocks, and just as little would 

 he ascribe to heat the origin of flint, agate, silicified wood, etc. 

 On the other hand, the recognised hypothesis of regional 

 metamorphism of the crystalline schists is an extension of 

 Mutton's conception of the action of heat and pressure upon 

 rocks. 



Hutton was the first to demonstrate the connection of 

 eruptive veins and dykes with deeper-seated eruptive masses of 

 granite, and the first to point out the differences of structure 

 between superficial lavas and molten rock solidified under great 

 pressure. In assuming that granite represents rock consoli- 

 dated from a molten magma, Hutton laid the foundation of the 

 doctrines of Plutonism as opposed to those of Neptunism. 



Again, no one before Hutton had demonstrated so effectively 

 and conclusively that geology had to reckon with immeasurably 

 long epochs, and that natural forces which may appear small 

 can, if they act during iDng periods of time, produce effects 

 just as great as those that result from sudden catastrophes of 

 short duration. 



Hutton's explanation of the uprising of continents, owing to 

 the expansive force of the subterranean heat, was not altogether 

 new, nor was it satisfactory. Neither had Hutton any clear 

 conception of the significance of fossils as affording evidence 

 of a gradual evolution in creation. Yet in spite of these dis- 

 advantages, Hutton's Theory of the Earth is one of the master- 

 pieces in the history of geology. Many of his ideas have been 

 adopted and extended by later geologists, more particularly by 

 Charles Lyell, and form the very groundwork of modern 

 geology. Hutton's genius first gave to geology the conception 

 of calm, inexorable nature working little by little by the rain- 

 drop, by the stream, by insidious decay, by slow waste, by the 

 life and death of all organised creatures, and eventually 

 accomplishing surface transformations on a scale more gigantic 

 than was ever imagined in the philosophy of the ancients or 

 the learning of the Schools. And it is not too much to say 

 that the Huttonian principle of the value of small increments 

 of change has had a beneficial, suggestive, and far-reaching 

 influence not only on geology but on all the natural sciences. 

 The generation after Hutton applied it to palaeontology, and 



