OF UN3TRATIFIED ROCKS AND VEINS. 153 



the accurate sciences ; but we may here infer, from a 

 balance of phenomena, that which we cannot de- 

 monstrate. 



There is yet a case of unerupted trap, of which Sky 

 produces a distinct example, and which is relevant to 

 the question under consideration. It has also been 

 observed elsewhere. In this instance, a mass of trap, 

 unterminated downwards, and of a conoidal form, is 

 seen, in a fair and deep section, covered by the secon- 

 dary strata, which are so bent over it as to be accom- 

 modated to its form. Here is a case precisely ana- 

 logous to that of an unerupted granite ; and it is 

 obvious, that when, in the progress of waste, its sum- 

 mit shall reach the surface, it will present an example 

 of unerupted trap, with the strata conforming to it on 

 each side, just as the primary are so often found to do 

 in mountains of granite. 



We may now inquire how these facts apply to the 

 state in which granite is supposed, by the postulate, 

 to be invariably found ; unerupted, and not lying on 

 the strata to which it is contiguous. 



The last case of trap quoted, is here applicable, and 

 perhaps more completely than would at first be 

 imagined. If it was not necessary that a protruding 

 and protruded mass of trap should in every instance 

 make its way through the superincumbent strata, 

 neither has it been in the case of granite. Even the 

 rigid sandstones of Sky have yielded to the pressure of 

 the trap ; and much more must it be believed that 

 this has happened in the case of granite, when the 

 softness and flexibility of the primary strata in its 

 vicinity are considered. I need scarcely add that the 

 volcanic elevations of strata, without eruption, present 

 the same analogies. 



There arc moreover circumstances in the con- 



