I>OMA1N 1. SIDEHOUS. 



MODE XV. SIDEROUS INTRITE. 



intrites. The rocks here called INTRITES, because crys- 

 tals or particles are imbedded in a paste, are 

 distinguished from Glutenites, in which the par- 

 ticles coalesce together with little or no visible 

 cement. The former have by the Germans 

 been styled porphyries, from a similarity of 

 structure ; but the interspersiori of a few crys- 

 tals, especially of felspar or felsite, substances as 

 common as mica, can hardly even be said to 

 alter the nature of the rock ; and such sub- 

 stances ought in geology to be classed with 

 their parent base; for while all these kinds of 

 pretended porphyries are classed under one head 

 by Werner and his disciples, great confusion 

 arises from their totally different natures. 



In the present work the intrites and glutenites 

 are classed under the several domains to which 

 they belong ; but as the bases are of different 

 kinds, it has been thought advisable to bring 

 them under one point of view, at the end of 

 each domain. As however the chief siderous 

 intrites are the genuine porphyries, the pre- 

 servation of that classical and universal name 

 will considerably restrict the present division. 



