PROFESSOR HEDDLE ON THE MINERALOGY OF SCOTLAND. 85 
chloropheite of Maccutiocn’s description, and of the Scuir Mohr of Rum, is 
as little “ chlorite-like ” as it is possible for anything to be. 
Dana, in classifying a mineral from Farée, which was analysed by 
ForcHAMMER, under the head of “Chloropheite,” cautiously adds—‘‘ The 
chemical identity of the original chloropheite of Maccuttocn from Scuir 
More, with that of Farée and the other localities has not yet been ascertained.” 
ForcHAMMER himself should have doubted their identity, seeing that he 
gives the mineral from Farée a gravity of 1-809, while MaccuLtocu’s mineral 
had a gravity of 2 - 02. 
FORCHAMMER’S mineral yielded—silica 32°85, protoxide of iron 21°56, 
magnesia 3°44, water 42°15; and is a totally different substance. 
That Maccuttocn’s mineral, obtained at so near-home a locality as Rum, 
should, during the sixty years which have elapsed since its discovery, never 
| have been analysed, was an enigma to the writer, until he noted the discoverer’s 
statement, that the small quantities he himself obtained were got from fragments 
lying at the foot of the slope, for he “ believed the Scuir-More to be everywhere 
| inaccessible.” A personal inspection of the locality, and some experience of 
the impossibility of landing at the spot except during the very calmest weather, 
| also aided in the explanation. 
| At the Scuir-Mohr of Rum igneous rocks of an acidic, felspathic type (syenite, 
| Maccuttocs) have burst through and tilted strata of red “Cambrian” sandstone, 
| while mixed beds of amygdaloid and basalt have overflowed these strata merely 
| as far as the ruptured edges of the sandstone, and hang over their upturned 
| slopes as a capping and encircling cliff. 
At the northern end of the upturn, the angle of the tilt may be 45°; at the 
| southern, near the point of Bridianoch, it is about 78°;—vast and unbroken 
| sheets of sandstone rising here aloft to a height of about 800 feet. 
Toppled pillars and lumps of amygdaloid from the impending cliff could find 
| no resting-place on such a slope as this; and it was only when the waves had 
eaten out a shore terrace, and the gradually accumulating heap of debris crept 
up the gentler-angled portions of the slope, that the loose material assumed its 
| own angle of rest. When the rich “trap-grass” clad it, however, the still 
| falling materials were arrested before they reached the sea, to be grown over in 
| turn, and serve to impede the fall of others; so that there has come to be a 
| gradual sheathing and enveloping of the original rock-slope by a mass of 
| loose material which is devoid of all attachment to its immediately sustaining 
base. Hence there are constantly recurring stone-avalanches,—the slope being 
over 1100 feet in height,—these leave gashes in its substance, the crossing of 
| which broken ground may, through a slight disturbance, set much of the over- 
| | hanging slope in motion. 
Where grass-clad, the slope is, to well-tacketed boots, nothing beyond an 
