436 A POPULAR EXPOSITION OF THE 
Townships, forming both semi-crystalline and compact or steatitic 
beds. (See Part II. above, page 158.) These are of a light-green, 
silvery-white, or greenish-grey colour. Some of the beds of the 
Laurentian series, as in the neighbourhood of Marmora, &c., are also 
somewhat talcose, or contain interstratified layers of tale. Taleose 
slates occur likewise amongst the Huronian strata. 
Serpentine.—Serpentine rock, or Ophiolite, occurs in extensive 
beds amongst the metamorphic strata of the Eastern Townships. Its 
mineralogical characters have been already given (ante, page 159), 
but the rock, it may be stated here, is essentially a hydrated silicate 
of magnesia, more or less sectile, and of various colours, but chiefly 
dark-green, greenish-grey, or greenish-white, often with red or bluish 
veins, or variously mottled. It is very commonly mixed with carbo- 
nate of lime or dolomite, forming serpentine-marbles of green, choco- 
late-brown, and other colours. In Bolton, Ham, and other townships 
of this district, beds of chromic iron-ore are associated with these 
serpentine rocks; and a bed of magnetic and titaniferous ore, fifty — 
feet in thickness, occurs in the serpentine of Beauce. A large deve- 
lopment of serpentine rock, fit for economic purposes, occurs also with 
chromic iron-ore at Mount Albert, in Gaspé. According to Mr. 
Richardson (Report for 1850), the rock-exposure at this locality pre- 
sents vertical cliffs of several hundred feet in height, and covers an 
area of not less than ten square miles. 
Diallage Rock.—This rock consists principally of the mineral 
called diallage (see page 159, above), or of diallage and chlorite. It 
has a clear green or pale-bronze colour, is more or less fissile, and 
occurs in association with the serpentines of the Eastern Townships, 
to which, also, it is very closely allied. 
Quartz Rock, or Quartzite.—The rock thus named appears to have 
been formed by the alteration of sandstone strata. It has a more or 
less vitreous aspect on newly-fractured surfaces, is very hard, and is 
either colourless, or yellowish, greenish, pale red, brownish, &c. It 
occurs abundantly amongst the Huronian rocks of the north shores 
of Lakes Huron and Superior; and also amongst the Laurentian 
strata of many localities, as at St. Jérome and elsewhere. A remark- 
able quartz-conglomerate, containing pebbles of red jasper and white 
quartz in a colourless or pale-yellowish quartzose base, is met with in 
the Huronian formation of the Bruce Mines district ; and other con- 
glomerates of a somewhat similar character occur in the Laurentian 
