PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 319 
These analyses show the lime garnets to occur in primitive limestone ; the 
magnesian garnet in igneous rock ; and common garnet in micaceous gneiss, 
and at one locality in diorite. 
The new manganesious variety is found in granitic veins, which lie in 
micaceous gneiss. 
The vein which carries garnet at Glen Skiag is probably the same which is 
seen at Struay Bridge; the similarity in appearance and composition of the 
garnet which occurs in these veins may aid in identifying them. 
At one time I indulged the expectation that the occurrence of garnet in 
the limestones which are found towards the upper reaches of the Dee would 
enable us to follow out the bed or beds throughout the numerous and far- 
reaching windings to which they have been subjected. The two great beds of 
lime which course up the country from the west and east of Portsoy,—the 
westerly beneath, the easterly above the quartzite,—may without difficulty be 
traced until they approach the upper portions of the Don—into the vicinity in 
fact of the granite. Here, from a direct, they are suddenly thrown into a much 
winding course; and here they come into near proximity with an altogether 
different bed, which, with a general west and east ‘trend, undulates down the 
valley of the Dee. 
To follow out their relationships, and even to determine their identity in 
this highly disturbed district, is a problem of much difficulty. 
If it could be proved that the garnet was confined to one bed—that in which 
it first appears to the westward on the slopes of Leach Ghorm, and which can 
be clearly traced to Creag Mohr,—then it must be held that this bed takes a 
sudden sweep to the northward, and is that which, with a westerly dip, is seen 
in Glen Gairn. It must also be held that it is this same bed which, having 
formed an anticline—now denuded off—reappears with an easterly dip at 
Crathie, and, crossing the river to Boultshoch, is again seen at Corn Tullich,— 
henceforth holding an almost rectilinear course as far at least as Eslie.* 
But it is probably as correct a view to hold that the limestones become 
garnetiferous when they are approached by the granite, or became partially at 
least involved in that process, which in their near neighbourhood resulted in 
granitic formation. If so, the Glen Gairn, if not also the Crathie lime, must 
be regarded as the continuation of the great north and south bed last seen in 
the neighbourhood of Tornahaish. 
It is to be looked for that the occurrence of the garnet may aid in the de- 
termination of the true position of the limestones in this troubled district. 
* The localities at which this west and east bed is to be seen are—Leach Ghorm ; near Carn na 
Cuimhne ; on the south of the Dee in the Balmoral Park; on Creag Mohr; at Boultshoch ; at Corn 
Tullich ; in Knappy Park, at Aboyne; at Craigs, Muir, Midstrath, and Wood Cottage, in Birse ; - 
west of Arbeadie, Banchory ; on the Aberdeen road, near Banchory; east of Feugh Bridge ; and in 
three or four spots on the Hill of Tilquihillie. That only one bed appears at all these spots may 
however be doubted. 
VOL. XXVIII. PART II. 40 
