GRANITE, 87 



tmthought of by all geologists : but, because so much 

 of the history of both granite and trap depends on it. 

 I need only repeat, that in what follows, granite is 

 considered as a conventional rock, determined by infe- 

 riority of position. 



Notwithstanding this inferiority, we must not grant, 

 as asserted, that granite constitutes the mass of the 

 globe, or is the lowest rock in existence. Of its 

 interior, we know nothing ; but its weight is suf- 

 ficient to prove that it is not formed of granite. 

 Respecting the other assertion, there is neither expe- 

 rience nor reason in favour of it. Some unstratified 

 matter, solid or fluid, does doubtless lie beneath the 

 stratified surface of the earth ; but while conjectures 

 are fruitless, it might, if solid, be basalt, as well as 

 granite. But, omitting all speculation, the volcanic 

 rocks of Auvergne have flowed from beneath, through 

 granite, and contain a large proportion of iron, while 

 that rock contains very little. Hence, it is not there 

 the lowest substance. 



The same persons have also considered it the first 

 rock that was formed. Though treating of it first in 

 order, it is plain that it is not so viewed here ; while 

 I need not re-discuss the relations of the stratified to 

 the unstratified rocks. It is sufficient that granite dis- 

 turbs the former, transmits veins through them, and 

 affects their mineral characters; while the. strata do 

 not follow it in that regular order in which they suc- 

 ceed each other, but are variously and confusedly 

 placed with regard to it, so that a single mass may 

 touch all the members of one series ; a property not 

 possessed by any stratum. This is posteriority ; 

 but it is a posteriority only where the fact of intru- 

 sion is thus proved. Rocks have been deposited 

 on it, as I shall immediately show ; and in examining 

 the revolutions of the Earth, I have rendered it pro- 



