618 GEOLOGY. 



history of the globe ; that all rocks basaltic, trap, and granite as well as the secondary 

 and tertiary beds had been produced by a series of depositions formed in succession 

 from water ; and hence the followers of Werner took the name of Neptunists, in the con- 

 troversy which ensued with the disciples of Hutton, who were called Vulcanists, as the 

 advocates of igneous action. Werner proceeded to generalise upon few and insufficient 

 data, taking Saxony as a miniature picture of the earth ; though even here many 

 appearances were overlooked or misinterpreted. The fallacy of his doctrine respecting the 

 aqueous origin of all rocks is now universally admitted ; but the faults of his system 

 should not blind us to the merits of the man, who was one of the first to recognise the 

 existence of natural groups of strata in a certain order of superposition, and who succeeded 

 in enthusiastically attaching some of the finest minds of the day to geological inquiry in 

 several instances, to aid in overthrowing the theory of the teacher. 



A contemporary of the Freiberg professor, in Scotland Dr. James Hutton proposed 

 views concerning the formation of the mineral masses, founded upon the phenomena of 

 universal nature, which, though ' little appreciated in his lifetime, at last completely 

 exploded the theory of the Neptunists, and now rank among well-established geological 

 doctrines. The object of Hutton was not to explain the origin of things, but to elucidate 

 their existing state, by the agency of known causes. The following propositions are the 

 leading features of his system : 



1. That a great portion of the crust of the globe is formed out of more ancient mate- 

 rials ; that all the stratified rocks consist of the remains of other strata, more ancient than 

 themselves. 



2. That the greater part of the present continents, having once existed in a sedimentary 

 state at the bottom of the sea, must have been consolidated by some powerful agent ; that 

 this agent is subterraneous heat, which is freed from the objections urged against it, by 

 the principle of compression restraining the volatility of many substances, which cannot 

 exist upon the surface except in the form of gas, and compelling them to remain in com- 

 binations impossible under the pressure of the atmosphere alone. 



3. That the stratified rocks, instead of having a horizontal position, being actually 

 inclined at various angles, or even vertical, being inflected, broken, and the portions 

 often detached from each other, beds of the same character occurring at various elevations, 

 and sometimes at the greatest heights above the sea, they have been raised, therefore, 

 by some expansive force acting from beneath, which approximates closely to the cause 

 of the volcano and the earthquake : this force is heat. 



4. That veins, whether metalliferous or composed of stony substances, are of posterior 

 formation to the strata which they intersect ; that their materials have generally been 

 melted, and ejected from below ; and that this condition extends to the masses of 

 whinstone, granite, and other unstratified rocks, which are sometimes interposed among 

 the sedimentary strata, and which have been forced up through or injected among them, 

 heat being the cause of the propulsion. Hutton appears to have arrived at these views 

 by a course of independent investigation, though anticipated in a few points by some 

 Italian writers ; and all modern observation has tended, while slightly modifying his 

 principles, to confirm and extend them in the main. There are no geologists of note 

 who do not agree in the following doctrines: that the granitic, trappean, and basaltic 

 masses are the result of simple fusion; that the rocks of igneous origin have been 

 violently injected among the stratified deposits, by an upheaving force, elevating and 

 indurating them, at various epochs ; and that this mighty power from within, is the 

 expanding property of internal heat, whatever be its nature or its cause. 



The igneous theory, during the life of its author, and for some years after his death, 

 encountered general neglect, and, from various quarters, virulent opposition. Some 



