ERA OF THE OLD RED SANDSTONE. 4j 



the next ensuing system. It may be called the Era of 

 the Oldest Mountains, or more boldly, of the formation 

 of the detached portions of dry land over the hitherto wa- 

 tery surface of the globe — an important part of the designs 

 of Providence, for which the time was now apparently 

 come. It may be remarked, 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 mountains of Scotland are older than the Alps 

 and the Appenines, as it is that civilization had visited 

 Italy and had enabled her to subdue the world, while 

 Scotland was the residence of " roving barbarians." The 

 Pyrenees, Carpathians, and other ranges of continental 

 Europe, are all younger than the Grampians, or even the 

 insignificant Mendip Hills of southern England. Strati- 

 fication tells this tale as plainly as Livy tells the history 

 of the Roman republic. It tells us — to use the words ol 

 Professor Philips — that at the time when the Grampians 

 sent streams and detritus to straits where now 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 palaeo- 

 zoic rocks, from their containing the remains of the earli- 

 est inhabitants of the globe — are of vast thickness ; in 

 England not much less than 30,000 feet, or nearly six 

 miles. In other parts of the world, as we have seen, the 

 earliest of these systems alone is of much greater depth — 

 arguing an enormous profundity in the ocean in which 

 they were formed. 



4 



