associated with small orange-red grains of rutile. The same substance (according to Sir W. Logan,) occurs also, mixed with magnetic iron ore, in a thick bed in serpentine, in Vaudreuil, Beauce County, C.E. Magnetic Iron Ore -Iron-black, with sub-metallic lustre and black streak. Occurs in monometric crystals (octahedrons and rhombic dodecahedrons, figs. 26 and 27), in amorphous masses of a granular or lamellar structure, and also in small grains. Strongly magnetic, often with polarity. H. 5.5-6.5; sp. gr. 4 9-5.2. Infusible, or nearly so. One hundred parts contain: Oxygen, 27.6; iron, 72.4; (or sesqui

Fig 26.

oxide of iron, 69; protoxide of iron, 31.) This when pure, is the most valuable of all the iron ores. Its black streak, and strong magnetism, (and, when crystallized, its form), easily distinguish it from specular iron ore. In the Laurentian rocks of Canada, it occurs in vast beds, rendering this Province one of Fig. 27. the richest iron-containing countries of the world. It occurs also abundantly amongst the metamorphosed Silurian strata of the Eastern Townships. Its principal "Laurentian" localities comprise the Townships of Marmora, Belmont, and Madoc, with those of South Sherbrooke, Bedford, and Crosby, in Canada West; and the Townships of Hull aud Litchfield, on the Ottawa, in Canada East. The supply at these localities is apparently inexhaustible. The Townships of Bolton and Brome, and the Chaudière Valley, may be cited amongst the localities of this ore in the metamorphic district south of the St. Lawrence. In this district, however, as remarked by Sir William Logan, its value is much lessened by admixture with titanic iron, chlorite, &c. In the form of black magnetic sand (either alone or mixed with iserine, ), this ore is also of exceedingly common occurrence on the shores of many of our lakes, islands, &c. The black iron-sand of the Toronto "Peninsula" is a well-known example.

Iserine. This is a black titaniferous iron ore, bearing the same relation to Magnetic Iron Ore that Ilmenite bears to Specular Iron. It occurs chiefly in the form of magnetic sand, or in small granular masses, mixed with magnetic iron ore. It occurs with "iron sand " on our lake shores, &c., and probably with magnetic iron in the Eastern Townships. It can only be distinguished from the latter mineral by a blow-pipe (or other chemical) examination. Fused on

charcoal with microcosmic salt in a reducing flame, the glass becomes, on cooling, deep red.

Chromic Iron Ore.-This substance is also closely related to Magnetic Iron Ore. It has a black colour, with sub-metallic lustre, and dark-brown streak. It occurs commonly in amorphous granular masses, and consists normally of sesqui-oxide of chromium and oxide of iron. H. 5.5; sp. gr. 4.3-4.6. Bolton and Ham, in the "metamorphic district" of the Eastern Townships (where it occurs in veins of about a foot in thickness, in serpentine) are its principal Canadian localities. It is found also in other places throughout this district, in small grains, in dolomite and magnesite rocks. When quite pure, it may be distinguished from magnetic iron ore by its. brown streak and lower sp. gr. ; as well as by its want of (or feeble) magnetism. Chromic Iron Ore is used for the preparation of chromium compounds, employed in dyeing, painting, &c.

Brown Iron Ore (Limonite).-Brown of various shades, with submetallic (or sometimes stony or silky) aspect, and yellowish-brown streak. Occurs chiefly in botryoidal masses with fibrous structure (a variety often called Brown Hæmatite), and also in vesicular and earthy amorphous masses (Bog Iron Ore). H. 5.0-5.5; sp. gr. 3.5-4 0. Blackens before the blow-pipe, and becomes magnetic. In the bulbtube (fig. 22) it gives off water. One hundred parts contain (if the substance be pure): Sesqui-oxide of iron, 85.6; water, 14.4. This is likewise a valuable ore of iron. The Bog Iron Ore variety (in addition to yellow ochre described in Section D 3) is that which chiefly occurs in Canada. This variety is a comparatively recent product; and its formation, indeed, is still going on in places, by deposition from water in the form of carbonate of iron oxide, this being afterwards converted into the hydrated sesqui-oxide. It occurs in great abundance in Post-tertiary deposits in the Three Rivers District, C.E., (yielding the celebrated "St. Maurice, or Three Rivers Iron," largely employed for castings); and also in the County of Norfolk, C.W.; besides many other localities. Altogether, the following Townships and Seigniories are enumerated by Sir William Logan (Esquisse géologique du Canada) as yielding this ore: Middletown, Charlotteville, Walsingham, West Gwillimbury, Fitzroy, Eardley, March, Hull, Templeton, Vaudreuil, St. Maurice, Champlain, Batiscan, Ste. Anne, Port Neuf, Nicolet, Stanbridge, Simpson, Ireland, Lauzon, St. Vallier, &c. These bog iron ores always contain a small amount of

phosphoric acid, which becomes reduced during the process of smelting, and usually renders the iron (by the presence of phosphide or phosphuret of iron) "cold-short." Cold-short iron is more or less brittle, and, hence, as a general rule, it is only available for castings. The St. Maurice ores are said, however, to yield excellent malleable iron.

NOTE. As the minerals of this Section (A 4) present, in many of their varieties, a somewhat doubtful metallic aspect, they will be referred to again, under Group C.

B. Aspect metallic. Hardness insufficient to scratch glass.

B 1. Malleable or Ductile.

[Principal Minerals:-Colour yellow: Native Gold. Colour white, with dark tarnish: Native Silver, Colour dark lead-grey: Sulphide of Silver. Colour copper-red: Native Copper.]

Native Gold.-Rich golden-yellow; in small granular or subcrystalline masses, scales, and dust. Sp. gr. varying from about 16.0 to 19.0. Easily fusible, but otherwise inalterable before the blowpipe. Distinguished by this latter character, and also by its high sp. gr., its malleability, &c., from copper pyrites, iron pyrites, and other substances of a similar aspect. Another salient character, applicable more especially to dust gold, is the quality of remaining unaffected by nitric acid. In Canada, native gold occurs over a wide area (in alluvial sands, &c.) in the metamorphic district south of the St. Lawrence, although not in sufficient abundance to cause the regular working of the auriferous sands of this district to be remunerative. The sands of the following streams and rivers, more particularly, are stated by Sir William Logan to contain gold: The Guillaume, Lessard, Bras, Touffe-des-Pins, Du Lac, Famine, Du Loup, Metgermet, and Poser's stream; with the Chaudière and St. Francis. These, with the exception of the St. Francis, belong chiefly to Beauce Co., C.E. Sir William Logan states also, that native gold has been found in small quantities in a vein with Specular Iron Ore, in the township of Leeds, Megantic Co., C.E. Traces of gold have likewise been discovered in the native silver of Prince's Mine, Lake Superior. (See, also, auriferous varieties of Iron Pyrites, A 1; Copper Pyrites, B 3;

* The term "aspect," as here employed, refers not merely to the "lustre" of the substance, but to its general appearance and characters, taken together. Thus but few, if any, specimens of Bog Iron Ore exhibit a metallic lustre properly so-called; and yet most persons, on taking up one of these specimens, would refer it at once to the metallic group, or, in other words, would consider it to be a metallic substance of some kind,

and Blende, B3.) The gold of the Eastern Townships contains, according to Professor Sterry Hunt, from 11 to 13 per cent. of silver. Small grains of Platinum and Iridosmium are mixed with it here and there, as in the sands of the Rivière du Loup, &c.

Native Silver.-Silver-white, often with dark or yellowish external tarnish. Found chiefly in crystalline arborescent groups, and in small, scaly, granular, or wire-like masses, associated with native copper, at St. Ignace and Michipicoten Islands; and with sulphide of silver, &c., in calcareous spar, at Prince's Mine, Spar Island, Lake Superior. Sp. gr. 10-11. Easily fusible.

Sulphide of Silver (or Silver Glance).-Dark lead-grey or black, with shining streak. Perfectly ductile. Chiefly in small masses with native silver, sulphide of copper, galena, malachite, &c., in a vein of quartz and cale spar, at Prince's Mine, Lake Superior. Sp. gr. about 7.2. Fusible and reducible to metallic silver per se before the blowpipe. One hundred parts contain: Sulphur, 13; silver, 87. It is easily distinguished from sulphide of copper, galena, &c., by its perfect malleability, as well as by its blow-pipe characters.

Native Copper-Copper-red, with shining streak. Chiefly in arborescent and amorphous masses, more rarely in determinable crystal-groups (Monometric.) H. 2.5-3.0. Perfectly malleable. Sp. gr. about 8.9. Easily fusible, imparting a green colour to the flame. Native copper occurs in immense abundance on the south shore of Lake Superior, but on the Canada side of the lake it has been found in small quantities in St. Ignace and Michipicoten Islands. In the latter Island, at Maimanse and Mica Bay, accompanying copper glance and copper pyrites. It does not appear to occur at all amongst the extensive deposits of copper pyrites, &c., on Lake Huron. In the Eastern metamorphic district, native copper is said to have been noticed at St. Henri, Dorchester County.

B. 2. Yielding to the Nail

[Principal Minerals: Streak white, Mica. Streak black, colour, black or dark. grey: Graphite. Streak and Colour lead-grey; imparting a pale green tint to the blow-pipe flame: Molybdenite.]

Mica :-In laminar or scaly masses, with a false pearly-metallic aspect. Colour, various; streak, white. See Section D. 4.

Graphite:-Chiefly in black or dark-grey foliated masses or small scales. Feels somewhat greasy; marks on paper; sectile, and flexible

in thin pieces; H. 1.0-2.0; Sp. gr. about 2.0. Inalterable before the blow-pipe. It occurs in small scales disseminated more or less throughout our Laurentain formation, and more especially in the crystalline limestones of that series; but its principal Canadian localities are the townships of Grenville (Addington County,) and Fitzroy (Carleton County,) on the Ottawa. At the former locality it constitutes several veins, each of an average thickness of about five inches; and is associated with garnets, zircon, feldspar, and other minerals. Graphite when of fine granular structure and dark colour, is extensively employed, under the popular name of Plumbago or "Black-Lead," in the manufacture of the so-called black-lead pencils. It consists, however, simply of carbon (or of carbon mechanically mixed with oxide of iron,) and does not contain a trace of lead. Our Canadian graphite is unfortunately too coarse and not sufficiently intense in colour for pencils, but, according to Sir William Logan, it may be used in the manufacture of refractory crucibles. Some samples that we have seen, might be employed also when ground to powder, as a polishing material for grates and stoves.

Molybdenite :-This substance much resembles graphite, but is of a lighter colour; and whilst it leaves a black trace on paper, it makes a dull greenish streak on smooth porcelain. It occurs chiefly in small scaly masses of a lead-grey colour. Like graphite it feels somewhat greasy, and it is also flexible. H. 1.0-2.0; Sp. gr. 4.4-4.8. Infusible, but it colours the blow-pipe flame pale-green, and volatilizes very slowly, depositing a white crust of molybdic acid on the charcoal. One hundred parts consist of: sulphur 41, molybdenum 59. It is not uncommon in small quantities amongst our Laurentian rocks generally, and in the intrusive granites of that formation. As special localities, we may cite from the Reports of the Geological Survey: Jerome, C. E.; Mud Turtle Lake, north of Balsam Lake; the River Doré near Gros Cap; and a granite vein on the west side of Terrace Cove, Lake Superior. Molybdenite is the principal source of molybdenum compounds, used in porcelain painting, and as a reagent in certain chemical experiments, &c.

To this section belong also, Pyrolusite or Black Manganese Ore, and Sulphide of Antimony or Grey Antimony Ore. The former (a compound of oxygen 36.7, manganese 63.3) occurs chiefly in radiating fibrous masses of a black or dark steel-grey colour, and is quite infusible. We have received a specimen said to