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PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 473 
The ascent of Haiskeval from the north is, from the toppling condition of 
the huge blocks into which its aphanite beds have been rent, attended with 
yery considerable risk, and is, for a single individual, quite impracticable. 
Its beds show many transitions from coarse to fine grain, from loose to close 
structure ; from brown opaque to green translucent augite. The rock, besides 
the two ingredients mentioned, seems generally to contain yellow olivine ; 
bronzy Biotite is sometimes present ; martite in thin bands is an accessory ; and 
the occurrence of a radiated zeolite lends its aid to the proof of the matrix 
being of igneous origin. 
The continuation of this line of section leads to the claystone porphyry mass 
of Ben More, which is altogether similar to that of Scuir na Gillean. At the 
shore at Pappadill the sandstone is cut off, bent upon itself, and enveloped in 
trap, which takes the form of a coalescent bundle of vertical dykes. 
This is a fine-grained augitic rock, similar to the central mass; but as no 
connection can be shown to exist between the two, no argument can be drawn 
from it, or probably from the existence of a lake which obscures some faulting. 
A section drawn from the east shore a little south of Strone, westward to 
the point of Bridianach, or to Scuir More, shows first, the deep-seated green 
flags, here dipping slightly to the north-west: they are frequently coated with 
rock milk, and the cement of the gritty varieties is calcareous. Following 
these into the higher ground, we find, as we approach the craggy central rocks, 
that the dip is inverted ; and finally we have the augite rock showing itself on 
the crest of their ruptured and upturned edges. Passing over the central group 
of augitic hills, the land falls into a valley, the west side of which is entirely formed 
by the extended bulk of Oreval,—a felspathic or granitic hill (“syenitic granite”). 
The junction cannot here be seen on account of surface covering. At Harris, 
on the south shore, MaccuLtocu states that the one rock insensibly passes into 
the other. Seen from a boat, it seemed as if the augitic rock here exhibited 
intrusive features, and ramified for some little distance through the other, as 
though a restraining and pre-existent mass. 
Westward of the syenite, red sandstone, in enormous and high tilted beds, 
falls away to the west, forming sheeted and terrific slopes, at an angle of about 
78°, and probably of 800 feet in height. 
At the north end of Oreval, at Scuir More, and at a hill north of Oreval, 
amygdaloidal and basaltic rocks hang on to the skirts, or overlap the tops of 
the syenitic hills,—overlap unconformably the sandstone,—and overlie a denuded 
spur of the augite rock; these three connections being seen within a narrow 
compass. The many-bedded strata of these “trap rocks” dip slightly to the west. 
The conclusions to be drawn from these facts are, as regards Skye, small in 
amount, but they are irresistible. 
An igneous rock, of a granitic or felspathic nature, burst through, over- 
VOL. XXVIII. PART II. 6G 
