A Last of Minerals and Organic Remains. 63 
in long. 92°20’. In Rainy Lake, these crystals are ex- 
tremely small; in very oblique four sided, and injsix sided 
prisms, and in twin crystals. In both localities they are 
numerous, and imbedded in the same gneiss, which, with 
frequent transitions into mica-slate, greenstone, &c. here 
overspreads a great extent of country. 
In the river Lacroix, the staurotide occurs in the second 
portage from the lake, and is frequently an inch long, and 
two thirds. of aninch broad; and in excellent condition. 
Amethyst.— Lake Superior. Found also by Major De- 
lafield; (a remark which extends to all the minerals found 
in Lakes Superior and Huron.) It presents itself insix sided 
prisms of good color, in druses and geodes of amygdaloid. 
This rock occurs in great quantities, on the north shore 
of this lake, and in the adjacent islands. It is intimately 
connected with the old red sandstone formation, is adja- 
cent to, and passes into clay porphyry, which graduates 
into the sandstone. Limestone, with orthoceratites, tri- 
lobites, encrinites, and other fossils, characteristic of the 
oldest secondary rocks, is also close at hand. 
Rock Crystal.—Quebec, in transition limestone ; Lake 
Huron, in transition greenstone; Lake Superior, in amyg- 
daloid, &c. Rock crystals are found in the fissures and 
cavities of the limestone of Quebec, in extraordinary quan- 
tities, and of great brilliance. They are generally super- 
imposed laterally, or terminally, seldom imbedded. ‘Their 
form is the six sided prism, with the ordinary pyramidal 
acumination. They are often much flattened, seldom 
equi-angular, and frequently the prism disappears, leaving 
a dodecahedron. ‘The crystals are single or agglutinated ; 
being in the latter case, full of rents, and of brown earthy 
matter; and in rare instances, contain a drop of pale bitu- 
minous liquid. They are either colorless, or dark smoke 
brown. 
Radiated Quartz.—Point Marmoaze, Lake Superior, in 
amygdaloid, nearly filling a geode with imperfect crystals, 
radiating in.a stellular form from three centres. 
Milky Quartz.—In the outlet of Lake Ontario, four 
miles below Kingston, this species of quartz exists in large 
strata, subordinate and conformable to gneiss, and in the 
calcareous puddingstone covering it. 
