NOVA SCOTIAN GEOLOGY—HONEYMAN. 271 
Art. VI._—ARCH#HAN GNEISSES OF THE COBEQUID MOUNTAINS. 
—MaGnetitic.—By Rev. D. Honrtyman, D. C. L.,, 
F.S. A, &e. 
(Read March 14, 1881.) 
THE rocks to which attention is directed were first noticed in 
my second paper on the Geology of the Cobequid Mountains.— 
Tran. 1873-4, Vol. III, page 385. “South of the County line 
(Colchester and Cumberland) we have outerops of the next band. 
These exposures exhibit much greater variety than was seen 
on the Intercolonial Railway. In one exposure the strata are 
beautifully banded. The dark green homogeneous (microscopi- 
cally) diorites having interbedded red and green gneissoid strata. 
These exposures show massive homogeneous (microscopically) 
diorites and others show gneissoid and quartzite strata; and the 
last exposures, a little below the bridge, on the east side of the 
road, show dark green diorite, which may readily be mistaken 
for uncrystalline rock. The hammer, however, shows that it is 
characteristically hard and crystalline. These are succeeded by 
uncrystalline rocks on the Intercolonial Railway. The last are 
the rocks containing the Londonderry Mines iron deposits. The 
crystalline rocks on the south side of the central band of the 
I. C. R,, I have correlated with the “Lower Arisaig Series ”— 
Laurentian (Archean). 
The special part of the rocks described in the quotation to 
which I intend to direct attention, is the “Interbedded red and 
green gneissoid strata.” Specimens of the “red” from a stratum 
four inches thick were closely examined with a view to satisfy- 
ing myself regarding the hornblendic character of the dark lines 
which pervade the red feldspar (orthoclase). Contrary to expec- 
tation I found the lines to consist of magnetite in grains. A little 
hornblende and mica also occur. Thinner red strata as well as 
the green associated, have also grains of magnetite in abundance. 
The magnet readily and beautifully separates the magnetite 
from the pulverized rock. 
The finding of magnetite in the gneisses in situ, led me to. 
