172 A POPULAR EXPOSITION OF THE 
rocks; but iron pyrites occurs chiefly in our Laurentian and Huro- 
nian Formations, and in the Metamorphic district of the Eastern 
Townships. The general reader will find these geological terms fully 
explained in some of the succeeding papers of this series. 
Radiated Pyrites, or Marcasite, also belongs to this Section, but it does not 
appear to have been noticed in Canada. It has the same composition as 
common Pyrites, but crystallizes in the Trimetric or Rhombie System. Many 
globular specimens, with radiated structure, sometimes referred to Marcasite, 
belong truly, it should be observed, to common Pyrites. 
A.2.—Colour, Pale Copper Red (usually with grey or black external 
tarnish.) 
Arsenical Nickel —Pale copper-red, tarnishing dark-grey. Streak, 
brownish-black. Chiefly in small amorphous masses. H. 5:0—5°5 (it 
scratches glass feebly.) Sp. gr. 7.3-7,7 (a salient character.) Fusi- 
ble, with strong odour of garlic. One hundred parts contain: 
Arsenic, 56; Nickel, 44. This substance, often called Copper- Nickel 
from its copper-red colour, is the common ore of nickel; but in 
Canada it is very rare. It has been found in small quantities in 
Michipicoten Island, Lake Superior. A substance composed of sul- 
phur, arsenic, and nickel, occurs likewise, but in very small quanti- 
ties, at the Wallace Mines, Lake Huron. It is somewhat less hard 
than Arsenical Nickel. ‘The Townships of Bolton and Ham, in the 
metamorphic district of the Eastern Townships, are also cited as 
localities of nickel ore. The ore is said to occur there very sparingly 
in Serpentine, associated with Chromic Iron Ore. 
A. 3. Colour, Tin or Silver-white (sometimes with grey or yellowish 
external tarnish.) 
Arsenical Pyrites (Mispickel.)—Tin or silver-white, inclining to 
light steel grey. Streak, greyish-black. In amorphous and granular 
masses, and in modified rhombic prisms (Trimetric System.) 
H. 5.5-6.0; Sp. gr. 6.0-6.4.  Fusible, with garlic odour, into a 
magnetic globule. One hundred parts contain: sulphur, 20; ar- 
senic, 46; iron, 34. This mineral is of very common occurrence in 
many countries. It is quite useless as an ore of iron, but is em: 
ployed in Germany and elsewhere in the production of arsenious acid, 
‘the white arsenic of commerce. Arsenious acid is obtained also, and 
more abundantly, from arsenical nickel and certain cobalt ores. In 
Canada, arsenical pyrites occurs in small quantities with common iron 
