222 



EIGHTEENTH CENTURY. 



PT. III. 



To prove whether this was so he made a journey to the 

 Grampians, where there are large masses of granite ; and 

 there, in Glen Tilt, he found the veins of red granite branch- 

 ing out into the clay-slate and limestone rocks above, as 

 in Fig. 37. It is easy in this diagram to see that the 

 water-made layers, a, b, must have been there before the 

 granite was melted, otherwise it could not have sent the 

 straggling veins, c c, up into them. And so he convinced 

 himself that some granites are newer than the aqueous rocks 

 which lie above them. It is said that he was so delighted 



FIG. 37. 



Granite Veins in Glen Tilt. 

 a. Clay slate, b. Limestone, c. Granite veins. 



at finding this proof that the guides who were with him 

 thought he had discovered a vein of gold. 



This is one out of many examples of the way in which 

 Hutton worked and corrected the mistakes which had 

 sprung up in the German school of geology. Werner had 

 taught his pupils that there was really something to be learnt 

 from the study of the rocks ; that they could be made to 

 tell real histories of the past and help men to get wealth for 

 the future, and thus he persuaded them to give time and 

 thought to this work. Hutton showed that to carry on this 

 study rightly they must open their eyes to all that is going 



