60 REPORT—1863. 
manganese, which was clearly detected in both analyses, would tend to bring 
the Crohy specimen out of the type of tale and into that of hornblende. 
Among the other more interesting minerals which have been found, we 
may mention molybdenite in crystalline plates, fibrolite, kyanite, schorl (ex- 
tremely abundant), and the minerals which have been already mentioned as 
occurring in the altered limestones. 
I. Ardmalin, near Malin Head.—Coarse-grained granite, composed of 
(a). Quartz; very conspicuous (1 in. crystals). 
(). Red orthoclase feldspar (1 in. crystals). 
(c). Green mica; in small nests, resembling chlorite. 
II. Urrismenagh, near Dunaff Head.—Medium-grained granite, containing— 
(a). Quartz; not very visible. 
(6). Pink feldspar ; probably orthoclase (+ in. crystals). 
(c.) Grey feldspar ; probably oligoclase (1 in. crystals). 
(d). Black mica; ;4, in. crystals; occasionally passing into a dark 
' blackish-green mica, in small nests and resembling a mix- 
ture of chlorite and hornblende. 
III. Glen.—Coarse-grained gneissose granite, containing— 
(a). Quartz; scarcely visible, broken, transparent, grey. 
(6). Red feldspar; probably orthoclase, forming large crystals (partly 
made up of pink translucent feldspar, with bright reflexion), 
dull waxy lustre, opaque. 
(c). Whitish translucent feldspar; probably oligoclase, and quite 
distinct from (6). 
(d). Green mica; abundant in streaks alternating, as in gneiss, 
with crystalline sheets of red and pink feldspar. 
IV. Glen.—Coarse-grained gneissose granite, apparently in beds in the gra- 
nite No. III., and containing— 
(a). Whitish feldspar; anorthic, semiopaque, and sometimes in 
macles, probably oligoclase (crystals 4 in, by 1in.). 
(6). Jet-black mica; in great abundance, probably equal to the 
feldspar, which occurs in rounded masses imbedded in the 
black mica, which itself occurs in streaks as in gneiss. 
V. Glenveagh.—Beautiful, coarse-grained, porphyritic granite :— 
(a). Feldspar ; conspicuous, pink (crystals 4 in. to 2 in.), orthoclase. 
(5). Quartz; inconspicuous, grey, transparent, with rounded an- 
gles. 
(c). Mica; jet-black, abundant in minute grains; the black mica 
and pink feldspar give character to the rock. 
VI. Glenveagh.—Fine-grained gneissose granite :— 
(a). Quartz, scarcely visible, grey. 
(4). Feldspar; white, sugary, facets rare, and, when they do occur, 
semitransparent—probably oligoclase. 
(c). Mica; perfectly black, high lustre. 
VII. Poison Glen.—Medium-grained granite :— 
(a). Quartz; grey, not prominent. 
(6). Feldspar; pink, in large crystals (Lin. by } in.), semitranspa- 
rent, predominant ; orthoclase. 
(c). Mica; jet-black, bright lustre. 
