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XXIV.—Chapters on the Mineralogy of Scotland. Chapter First.—The Rhom- 
bohedral Carbonates. Part I. By Professor HEDDLE. 
(Read April 3, 1876.) 
In the series of chapters of which the present is the first, I purpose to 
submit the results of an analytical examination of all the minerals of Scotland 
whose composition appeared doubtful; of such as had not previously been 
examined; or of such as appeared in any way to be of special geologic 
interest. | 
In every case, where not otherwise stated, the specimens were gathered by 
the hands of the writer himself; while the purity of every particle examined 
was as far as possible secured by an examination under the lens, conducted 
with the most scrupulous care. All portions selected for the determination 
of the specific gravity were afterwards divided into small fragments (in the 
event of any impurity being observed, the determination was discarded); the 
fragments thus obtained were those employed for the analyses. 
Minerals belonging to the same group were as far as possible examined in 
succession. 
The substances first examined are comprehended in this first chapter. 
ANKERITE. 
Found by DupGEon and myself in 1873, in a vein of somewhat decomposed 
yellowish crystalline talc, on the west side of the Ting of Norwick, in Unst, 
Shetland, at the junction of serpentine with mica slate. 
This is an old and well-known locality, and is that referred to by Gree and 
Lettsom in their “ Manual of Mineralogy,” as the locality for Brewnnerite, when 
they say— Hitherto it has been met with in the United Kingdom only at the 
head of Norwick Bay, in Unst.” 
So well, apparently, had the locality been searched, that it was with difficulty 
that the mineral could be found, and then only one piece of some ounces in 
weight was obtained. This was a readily cleavable mass, composed of mutually 
penetrating crystals, of about one inch in size. Its colour was bluish grey; 
its specific gravity, 2°91; its cleavage angle, 106° 6’. 
VOL. XXVII. PART IV. 6 P 
