T. Sterry Hunt on Granitic Rocks. 123 
cleavable magnetite, the latter in masses sometimes two or three 
inches in diameter, scattered through the feldspar. 
5. The veins hitherto noticed occur in gneiss, but on the 
river Rouge one consisting of large masses of quartz and albite 
is found in crystalline limestone. A remarkable vein described 
by Sir William Logan in Blythefield, Ontario, traverses alter- 
nate strata of limestone and gneiss, and has a breadth of not less 
then 150 feet. It consists in great part of a coarsely cleavable 
pale green pyroxene (sahlite), with a dark green hornblende, 
phlogopite and calcite. Portions of the veinstone, however, 
consist of an admixture of orthoclase, quartz and black tourma- 
e 
spathic type of veins. In Ross, Ontario, a vein holds large iso- 
lated crystals of white orthoclase imbedded with black spinel, 
apatite and fluorite in a base of lamellar pink carbonate of lime. 
ne of the most remarkable of these composite veins is in Gren- 
ville, Quebec, and was formerly worked for “a ee It cuts a 
crystalline limestone, itself holding graphite an 
has afforded not less than fourteen distinct mineral species, viz : 
r 
scribed by Blake in Vernon, New Jersey (this Journal, II, xiii, 
116), in which calcite, fluorite, chondrodite, phlogopite, marga- 
rite, spinel, corundum, zircon, sphene, rutile, menaccanite, py- 
rite and graphite occur. Some of these contain barytine, and In 
one case I have observed natrolite, both seemingly one cavl- 
e 
ties, and of later origin than the other minerals remark- 
able zinciferous minerals, franklinite, zincite and dysluite, 
found in the Laurentian limestones w Jersey, appear 
in Moriah, New York, which includes angular fragments of the 
magnetite which forms its walls, and consists of a cleavable 
greenish triclinic feldspar, with quartz crystals having round 
angles, octahedrons of magnetite, allanite, and a soft greenish 
oganite. : : 
. regards ‘he order of deposition of minerals in 
— veins, we find apatite enclosed = in — in quartz, 
in phlogopite, in spinel, in graphite and in pyrite. 
hand, ace pee Calas aes 8 erystals of calcite 
or of quartz; and graphite, which itself encloses apatite, is 
found included alike in quartz, in orthoclase, in pyroxene and 
in calcite, in such a manner as to ead us to conclude that its 
crystallization was contemporaneous with that of all these 
