GEOLOGY. 



may be attributed the formation of sepa- 

 rate mountains. The formation of secon- 

 dary mountains seem also to concur 

 with what is generally observed in the 

 ordinary progress of crystallization, 

 where it is observed, that after one series 

 of crystals are formed of the least soluble 

 matters, others are then formed of those 

 substances which the fluid was able to 

 hold still longer in solution. It has been 

 objected against the system of crystalliza- 

 tion oi' rocks, &c. that nature seems to 

 perform nothing of that kind at the pre- 

 sent period ; but were this the fact, the 

 objection would not possess much force, 

 since a most satisfactory answer might be 

 yielded, by asserting that the operation 

 has ceased, in consequence of the task 

 being accomplished ; and, speaking with 

 respect to the granitic and phorphyry 

 rocks, all the materials being employed. 

 The formation of stone by crystallization 

 is, however, carrying on in various situa- 

 tions at the present moment ; the incrus- 

 tations formed in certain springs, and the 

 various stalactitic formations which take 

 place daily, are instances of this kind. 



The untitness of water to hold the sub- 

 stances forming the primitive rocks in 

 solution has been considered as a power- 

 ful objection : but it is to be considered, 

 that the menstruum cannot be supposed 

 to have been simple water, but, as Mr. 

 Kirvvan observes, this primitive fluid 

 must have contained all the various sim- 

 ple saline substances, and indeed every 

 simple substance, variously distributed, 

 " forming, upon the whole, a more com- 

 plex menstruum than any that has since 

 existed, and consequently endued with 

 properties very different from any with 

 which we have been since acquainted." 

 Geological Essays, P. II. 



Considerable difficulty must, however, 

 continue, in adapting any system which 

 confines the production of the various 

 geological phenomena, which present 

 themselves to our observation, to too few 

 and to too limited causes ; since, however 

 necessary it may be to refer the general 

 phenomena to the operation of one par- 

 ticularly powerful agent, it still must be 

 necessary to take into the reckoning the 

 sinking and the raising of particular spots 

 from subterraneous submarine fires; as 

 well as the changes produced by the sub- 

 version of lofty mountains, rapid and vio- 

 lent currents of water, and various other 

 powerful causes. 



By the preceding sketch of the nume- 

 rous systems which have been advanced, 

 and by these cursory remarks on some of 



the objections which have been made 

 against those which appear to possess 

 the greatest share of probability, the mind 

 becomes better prepared to attend to the 

 system of the celebrated Werner, to 

 whom, in the opinion of his learned and 

 zealous annotator, we owe almost every 

 thing that is truly valuable in this import- 

 ant branch of knowledge. For the pur- 

 pose of conveying some notion of this in- 

 genious system, the following sketch is 

 taken from the view of it, given in the 

 " Elements of Geognosy," by Professor 

 Jameson. 



Agreeable to this system, the earth is 

 supposed to have existed originally in a 

 state of aqueous fluidity, which is infer- 

 red from its spheroidal form, and from the 

 highest mountains being composed of 

 rocks, possessing a structure exactly re- 

 sembling that of those fossils, which have 

 as it were, under the eye, been formed 

 by water. From this circumstance it also 

 follows, that the ocean must have former- 

 ly stood very high over these mountains ; 

 and as these appear to have been formed 

 during the same period of time, it follows, 

 that the ocean must have formerly cover- 

 ed the whole earth at the same time. 

 Contemplating the formations of the 

 mountains themselves, Werner discover- 

 ed the strongest proofs of the diminution 

 of the original waters of the globe. Hfe 

 ascertained, 1st, that the outgoings (the 

 upper extremities as they appear at the 

 surface of the earth) of the newer strata 

 are generally lower than the outgoings 

 of the older, from granite downwards to 

 the alluvial depositions, and this, not in 

 particular spots, but around the whole 

 globe. 2d. That the primitive part of the 

 earth is entirely composed of chemical 

 precipitations, and that mechanical de- 

 positions only appear in those of a later 

 period, that is, in the transition class, and 

 thence they continue increasing, through 

 all the succeeding classes of rocks. This 

 evidence of the vast diminution of the 

 volume of water which stood so high over 

 the whole earth is assumed to be 

 perfectly satisfactory, although we can 

 form no correct idea of what has become 

 of it. 



By the earliest separations from the 

 chaotic mass, which are discoverable in 

 the crust of the globe, was formed a class 

 of rocks, which are therefore termed 

 primitive rocks, being chiefly composed 

 of silex, alumina, and magnesia, constitut- 

 ing, by their various intermixtures, 1, 

 granite ; 2, gneiss ; 3, mica-slate ; 4, clay- 

 slate ; 5, primitive lime-stone ; 6, primi- 



