A List of Minerals and Organie Remains. 65 
spar; the radiating fibres passing at the circumference in- 
sensibly into calc. spar. It is very handsome, and is almost 
identical with the Italian zeolite. White fibrous zeolite is 
not uncommon in the druses of the Trap Mountain of 
Montreal, associated with tables of feldspar, pyrites and 
chabasie. 
Stilbite.—In the amygdaloid of the north shore of Lake 
Superior. It is red, indistinctly crystallized, encrusting 
nodules of calc. spar, and lining druses. It occurs likewise 
in the conglomerate, interstratified with the amygdaloid. 
Chabasie.—Montreal Mountain, ina druse with zeolite ; 
form well defined, color perhaps originally greyish white. 
. Aventurine.——North east shore of Lake Huron, twenty 
miles east of the French River. The mineral inserted here 
under this name, has been also recognized by Dr. Troust 
and others, of Philadelphia. It is a pale flesh-red feld- 
spar, largely crystallized, and forming part of a vein of 
porphyritic granite of great size, traversing gneiss. It is al- 
most every where full of brilliant golden points, whichspar- 
kle with increased force, if held in particular lights. ‘This 
porphyritic granite prevails greatly in large contempora- 
neous masses, and wandering veins, in all the sienitic (or 
rather granitic,) districts of Lake Superior; but is most 
abundant in the gneiss of Lake Huron, and of Lakes La- 
croix and Laplarie, in 92° 20’ and 93° west longitude, and 
north from Lake Superior. This gneiss is of imperfect or 
tortuous stratification; full of hornblende in beds, lamin, 
and also disseminated. It seems to belong to the transition, 
or to the younger of the primitive rocks ; judging from its 
constant proximity to red sandstone, the oldest organic 
limestone, and to trap. 
Where the aventurine occurs, the gneiss is stratified in 
large and bold curves, which often run into knots of con- 
centric layers, many yards broad; but its general course 
is N. W., N. N. W. or N. by W. with a corresponding eas- 
terly dip. Very frequently it passes into a granite. 
Glassy Feldspar.—Lake Superior, in pitchstone porphy- 
ry. In Lake Huron, and Gun-flint Lake, in greenstone 
porphyry. In Lakes Superior and Huron, they are splen- 
dent, transparent imbedded four sided prisms, of a pale 
wine-yellow color. In Gun-flint Lake, they are in six sided 
prisms also—-equiangular--sometimes one and an halfinches 
Vou. VII.—-No. a 
