'Oarious parts of Scothind. 393 



seems the only very discriminating character. I think it necessary 

 also to mention that the hornblende rock exhibits the two sub- 

 ordinate varieties of hornblende slate and greenstone slate. 



Since 1 have already indulged in some cursory remarks on that 

 sort of nomenclature which tends to mislead, by confounding sub- 

 stances, I may be excused for suggesting a reformation in the terms 

 primitive greenstone and greenstone slate. These consist of mix- 

 tures of felspar and hornblende, in the latter case disposed in a 

 laminated form, and in the former without that regular structure. 

 Their title to greenstone, as far as colour is concerned, is still less 

 than that of the varieties of the trap family, as the felspar is (in 

 Scotland at least) always of a red colour. By the use also of the 

 term greenstone, and by the series which is formed of primitive, 

 transition, and floetz greenstones, the mind is naturally led to look 

 for a geological and natural connection between these rocks. But 

 the primitive greenstones belong to that class in which gneiss and 

 mica slate form the principal features, and which constitute that 

 great system of rocks of which hornblende in its several modi- 

 fications of hornblende rock, primitive greenstone, hornblende 

 slate, and greenstone slate, is only a subordinate and occasional 

 member. The geological character of the floetz greenstones, is 

 their independence with respect to the rocks with which they are 

 associated, and their intrusion, if I may so call it, among a regular 

 system of stratified bodies. The transition greenstones are, I con- 

 ceive, of a character merely arbitrary, and only so called because 

 occupying the same situation with regard to the trajisitioriy as the 

 former do with regard to the fleets rocks. 



Thus also, greenstones may be classed among the primitive, where 

 they occupy similar positions among primitive rocks. 



But the primitive greenstones to which I now allude, and which 



Vol. II. ^ v> 



