518 PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 
metamorphosed siliceous schists, if not into lepidomelane gneiss, on the one 
hand ; and into hornblende schist and serpentine on the other. 
That a rock, usually regarded as belonging to the basic igneous division,— 
passes into acidic sedimentary rocks,—and into a basic sedimentary rock. 
Question the second then is—+s it an igneous rock? I hesitate not to say that 
in the district of which I write, the great mass of the rock, namely, that passing 
from the harbour of Portsoy up the country to the south-west, following the 
quartzite throughout, implicitly yielding to its every sinuosity, and preserving 
an unvarying position to the contiguous strata, never cutting through them or 
displacing them in the smallest degree, is just as much a metamorphic rock as 
the quartzite beneath it or the schists above it. It is not quite so much a 
metamorphic rock, however, as the underlying serpentine, which will, in 
the sequel, be shown to be a product of a secondary metamorphism or trans- 
mutation of the diorite itself, and therefore not strictly a “product of the same 
epoch.” 
Such a deduction has never been entertained by CUNNINGHAME, who, 
throughout, regards the diorite (his syenite) as an igneous mass; he places it 
among the unstratified rocks ;—distinctly says, that he is to be understood as 
not endeavouring to call in question its igneous origin; and commits himself 
absolutely when he says: “It forms the base of the hills of Knock and Durn ; 
and in the former we found masses high up the acclivity, derived not impro- 
bably from veins in the quartz that caps it.” He also figures it in his map as 
extending for about two miles up the western side of Durn Hill; and this as 
an extension of that “ principal mass ” which he states appears as great beds 
included in, though sometimes crossing, the strata at Denbrae, now Whyntie 
Head. As Denbrae Head is some thousands of feet higher up in the series than 
Durn and Knock hills, CUNNINGHAME has placed himself in the dilemma of 
either making these hills cap strata much more recent than themselves ; or he 
must set down a hill of 1400 feet in height as being a mere fragment uplifted 
by the igneous rock, without alteration of its dip, or visible severance from 
those portions of the same stratum which are in no way associated with diorite. 
The above random speculation is, in fact, perhaps the only blot in a paper 
of extreme merit. 
The fact is, that there is no evidence that the dykes and beds at Denbrae 
connected with any principal mass of diorite ; and if they 
are, there is strong evidence which tends to disconnect such a “ principal mass” 
from the principal mass which is associated with the quarzite ; and which is 
clearly associated with it in this regard, that it lies perfectly conformably 
above it. 
No one who takes his stand on the diorite immediately to the west of the 
battery at Portsoy, and regards even the “coarse granular” rock as a whole, 

