34 Anniversary Address of the 



mentary strata which are in progress in deep seas, can very 

 rarely emerge and become visible to man till they have ac- 

 quired a high antiquity relatively to most of the lavas and 

 beds of mud, sand, and pebbles, which will be formed in the 

 interval of time between the origin of such subterranean or 

 submarine rocks and their exposure above ground. They 

 cannot, except in a few very disturbed regions, like the Alps, 

 emerge from the sea, or break out in the centre of a moun- 

 tain-chain, till a series of grand revolutions of the earth's 

 crust has occurred throughout many large areas. Lofty 

 cones of lava and scoriae will have been piled up, old rocks 

 will have been denuded or displaced, bent or fractured, and 

 new strata, thousands of feet thick, will have been formed, 

 besides the occurrence of several important fluctuations in the 

 organic world, before the nether-formed products of fire or 

 water are brought into view. Whenever these do appear, 

 their aspect will be strange and unfamiliar to human ob- 

 servers, such as might well belong to bodies formed in a part 

 of the great laboratory of nature, to which man has no ac- 

 cess. Such singularity in outward form and internal texture 

 will naturally be referred to an origin connected with the 

 beginning of things, if the mind be already prepossessed 

 with a belief that we are studying the monuments of a 

 planet, which has been passing from a chaotic or nascent 

 state to one of order and maturity, especially if the peculiar 

 rocks in question are found invariably to have claims to a 

 high relative antiquity. 



" Granitic eruptions," says M. de Beaumont, " have be- 

 come more rare in the more recent epochs ;" * and doubtless 

 it is most true, that, in the newer secondary and older ter- 

 tiary formations, the granitic rocks become more and more 

 exceptional ; but had we lived in the carboniferous or Per- 

 mian epochs, we might, I conceive, with equal justice have 

 declared the only granites then visible to be extremely an- 

 cient. The more quartziferous varieties, together with a 

 certain class of metalliferous veins, posterior in date to the 

 vegetation of the coal period, such as are now known to the 

 miners of Cornwall, or to those of the Ural Mountains, 



* Bulletin, 2d Series, vol. iv. p. 1299. 



