314 GEOLOGY. 



layers. These are termed by Werner floetz and 

 secondary rocks, and abound in organic remains.* 



The Plutonic, Huttonian, or Igneous Theory. 



The Huttonian system does not carry us back to 

 the original formation of the globe. It supposes that 

 the present dry land was at a former period the bed 

 of the ocean; consequently, the present strata were 

 not precipitated from a chemical solution, being ra- 

 ther composed of the ruins of a former world. 



Granite, the oldest Wernerian rock, is supposed by 

 the Plutonists to be of more recent formation than 

 the incumbent strata, being regarded as a substance 

 that has been erupted from great depths in a state of 

 igneous fusion, bursting through the strata in some 

 parts, and upheaving the whole from their submarine 

 situation. Trap rocks are conjectured to have been 

 formed by vokanic agency under the pressure of an 

 incumbent ocean. 



Geological Systems. 



The leading positions in which the Huttonian and 

 Wernerian systems agree are, that the present conti- 

 nents have been covered with the ocean ; and that 

 the materials of which the rocks and strata were com- 

 posed, were deposited by an aqueous fluid. But 

 from these points of agreement they widely diverge 

 in their explanation of the causes by which the con- 

 tinents were laid dry, the mountains elevated, and 

 the materials converted into stone. 



* The principal objection (for there are many others) to the 

 Wernerian theory is, that by far the greater part of the sub- 

 stances of which rocks are composed, are not soluble in water, or 

 require so large a proportion for their solution, that the capacity 

 of the whole globe, were it a hollow sphere, would be too small to 

 contain a sufficient quantity of the aqueous menstruum. Indeed 

 latterly the votaries of Neptune have nearly abjured their errors, 

 and ranged themselves under the banners of Pluto. 



