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XVII.— Chapters on the Mineralogy of Scotland. Chapter Fourth.—Augite, 
Hornblende, and Serpentinous Change. By Professor HEDDLE. 
(Read 1st April 1878.) 
AUGITE., 
Malacolite. 
(Ca Mg) Si. | 
Malacolite was first observed in Scotland by Dr Maccuttiocn, who included 
it with the second sub-species, under the name of Sablite. 
He, in his different works, noted its occurrence—“ near the church of Rodel 
in Harris, ’—“ in Tiree, —“ Glen Elg,”—“Glen Tilt,”-and “in Rannoch.” With his 
usual power he describes the occurrence, varieties, and even the crystalline 
form of the mineral,—the clearness and precision of his descriptions being only 
equalled by the utter want of precision and frequent mystifications as to their 
localities. 
The above sentence conveys all the direct information which Dr MaccuLiocu 
youchsafes as to the five localities ¢ndicated by him, though in a vague manner 
he may occasionally lead one to conjecture that certain particular spots are 
meant. 
By the time that the mineralogist, led by Dr MaccuLtocn to Glen Elg, 
Tiree, or Rannoch, has walked some twelve or twenty miles in an unsuccessful 
search, he begins to think that if he be successful, he has some claim to be 
himself regarded as an independent discoverer. 
From Granular Limestone. 
1. Found at Shinness, Sutherland, sometimes imbedded in distinct layers of 
the lime, and occasionally at its point of contact with the inclosing gneiss. 
The mineral here is both in larger quantity and in larger crystals than else- 
where in Scotland. Frequently it is found in widely radiating crystals, which 
are, however, imbedded in the lime. Crystals from a foot to sixteen inches in 
length, by an inch or two in breadth, occur ; these are frequently fissured trans- 
versely—delicate amianthiform fibres stretching over the gaps to connect the 
severed portions. 
It is here associated with the following large assemblage of minerals :— 
Sahlite, abundant. Actynolite, scarce. 
Biotite, common. Sphene, scarce. 
Molybdenite, very rare. Apatite, rare. 
Pyrrhotite, rare. Augitic tremolite, rare. 
WOU, XXVIII. PART II. 6B 
