M . B. Studer on the Origin of Granite. 297 



a primitive gneiss or mica-slate, and one which is the product 

 of metamorphosis, and between a primitive and a more recently 

 formed granite. To such skill as this, however, I make no 

 pretensions ; and all such discriminations have hitherto inva- 

 riably appeared to me altogether arbitrary, and the result of 

 far too limited observation. 



Turn we therefore from these mineralogical characters, at 

 least till better taught, to geological ones : And here we must, 

 on the one hand, state it as an undisputed and observed fact, 

 that granitic syenites, granitic gneisses, diallage or gabbro- 

 rocks, gabbro-slates, talc and mica-slates, cover for miles 

 sedimentary deposits containing petrifactions ; it must also 

 be allowed that there is an intimate union between these 

 rocks and sedimentary rocks, through the medium of gradual 

 transition : these facts allowed, it may then be inquired 

 whether the dogma that granite forms the general basis or 

 ground-work of all formations, and is peculiarly the original 

 rock of the earth, reposes on a very sure or fixed foundation. 

 Probably, we should not entertain any doubt about this con- 

 clusion, were we to consult oiu' elementary treatises only, or 

 were we simply to notice upon our elegantly coloured sections, 

 the large red masses on which the name of granite is pre-emi- 

 nently conspicuous. On more mature reflection, however, this 

 opinion cannot but be regarded as doubtful, nor recognised as 

 any thing more than a mere dogma or article of belief, not an 

 object of actual observation. For, were we to bring forward 

 ever so many examples, in which the deepest deposits disco- 

 vered in numerous points are not granite but some other rock, 

 still it would be objected that granite may lie beneath ; could 

 we demonstrate that most of the minutely examined granitic 

 districts, are evidently of recent formation, as well as the 

 strata which lie immediately beneath and above them, still it 

 might be asserted that these upraised granites prove nothing 

 more than the presence of a deeper lying general granitic 

 mass ; and were we to extend this conclusion to all massive 

 rocks, that we might gain a wider field for the action of me- 

 tamorphosis, then we ai'e called to believe in the unpropor- 

 tionably greater distribution of granite by including all por- 



