62 VESTIGES OF THE 



that volcanic disturbances and protrusions of trap took 

 place throughout the whole period of the deposition of 

 the primary rocks ; but they were upon a comparatively 

 limited scale, and probably all took place under water. 

 It was only now that the central granitic masses of the 

 great mountain ranges were thrown up, carrying up 

 with them broken edges of the primary strata; a process 

 which seems to have had this difference from the other, 

 that it was the effect of a more tremendous force exerted 

 at a lower depth in the earth, and generally acting in 

 lines pervading a considerable portion of the earth's 

 surface. We shall by-and-by see that the protrusion of 

 some of the mountain ranges was not completed, or did 

 not stop at that period. There is no part of geological 

 science more clear than that which refers to the ages of 

 mountains. It is as certain that the Grampian moun- 

 tains of Scotland are older than the Alps and Apennines, 

 as it is that civilisation had visited Italy, and had enabled 

 her to subdue the world, while Scotland was the resi- 

 dence of "roving barbarians." The Pyrenees, Carpa- 

 thians, and other ranges of continental Europe, are all 

 younger than the Grampians, or even the insignificant 

 Mendip Hills of Southern England. Stratification tells 

 this tale as plainly as Livy tells the history of the 

 Koman Hepublic. It tells us — to use the words of 

 Professor Phillips — that at the time when the Gram- 

 pians sent streams and detritus to straits where now 

 the valleys of the Forth and Clyde meet, the greater 

 part of Europe was a wide ocean. 



The last three systems — called in England, the Cum- 

 brian, Silurian, and Devonian, and collectively the 

 palseozoic rocks, from their containing the remains of 

 the earliest inhabitants of the fiflobe — are of vast thick- 



