148 



Werner's theory. — age of trap rocks. 



According to the theory of Werner, all the superficial parts of the 

 globe were once in a state of aqueous solution, from which the ma- 

 terials were, at first, separated by chemical deposition in a crystalline 

 state, and formed a thick mass of granite round the globe. Upon 

 granite, the primary rocks were successively deposited, forming lay- 

 ers over each other like the coats of an onion. Over these again 

 were laid the transition rocks ; and next, the earthy stratified rocks. 

 Each of these layers was supposed to encircle the globe, or to be an 

 universal formation. While this process was going on, the waters 

 were gradually retiring, and became turbid : hence the materials 

 which they deposited, to form the upper strata, were more earthy 

 than those of the primary rocks ; they were also intermixed with 

 fragments of the rocks previously formed. According to this sys- 

 tem, mountains and valleys were caused by the original inequality of 

 the nucleus of the earth. So far, the parts of Werner's theory are 

 consistent; and we have a world ready made, in which every thing 

 might be supposed to remain quiet ; but — non sic Fata sinunt ; — 

 Neptune, ashamed of his late retreat, and indignant at his confine- 

 ment in such narrow limits, calls the infernal deities to his assistance, 

 and rising in his might, once more takes possession of the globe. He 

 covers it with the depurgations of his turbid waves : but, again he is 

 compelled slowly and reluctantly to retire from the field, leaving be- 

 hind him the basaltic rocks, the monuments of his triumph and his 

 shame. Such is, in substance, the theory of Werner respecting the 

 origin of all the superincumbent rocks of basalt and trap. They 

 are, also, according to this theory, universal formations. It is scarce- 

 ly possible for the human mind to invent a system more repugnant 

 to existing facts. W^ere basaltic rocks deposited from a solution 

 which covered the globe after the formation of secondary strata, as 

 Werner supposes, every part of the dry land and every valley must 

 have been incrusted or filled with basalt, — it would be the prevailing 

 rock of every district. On the contrary, basalt exists, only in par- 

 ticular situations, forming dykes, and overlying masses or beds of 

 limited extent : nor do fragments of basalt occur, in any quantity, to 

 warrant the belief that it was ever formed universally over the globe: 

 and what is here said of basalt, applies equally to all unconformable 

 rocks of porphpry, and the other trap rocks. Nothing but the ob- 

 scure language in which this doctrine of Werner was advanced, 

 could have prevented its absurdity from being instantly perceived 

 and acknowledged. 



W^ith respect to the relative age of trap rocks, it is evident, that if \ 

 they are of igneous origin, they may have been formed at any period. | 

 We have certain indications that basaltic rocks were formed at differ- 

 ent epochs ; some of the basaltic dykes which cut through the coal ^ 

 strata in the northern counties, do not enter the magnesian limestone | 

 that covers the coal strata. Hence it is clear, that such basaltic i 

 dykes were formed before the magnesian limestone was deposited : i 



