MINERALS

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from impurities, it is known as china clay and is used in the manufacture
of white table ware, electrical porcelain wall tile, as an ingredient in ceramics,
 and as a paper filler. Kaolin is not a high priced product, the average
price being below $10 per ton. The large porportion of quartz, necessitating
 expensive washing treatment, and unfavourable market conditions
have led to the suspension of operations since 1923.

Building Materials.—The value of the production of. building
materials constitutes more than one half of the mineral production of the
province For the year 1927 this value amounted to $15,382,957. The
list includes limestones, granites, sandstone, marble. slate. clav-brick,
shale-brick, cement, lime and sand.
Deposits of limestone capable of supplying unlimited quantities of
building stone, stone for road-making, raw material for the manufacture
of lime and cement, are found in practicallv all settled parts of the province.
 The constantly increasing use of cement concrete creates a greater
demand for crushed stone every year. Rural road maintenance also calls
for large quantities of crushed stone.
The granite resources of the province are extensive. The production
of some thirty quarries in 1927 amounted to $750,000. The granites most
commonly used are, the grey granites of the Appalachian chain; the
black granite of the Monteregian hills; granitoid rocks of various colours
of the Laurentian hills; the Canadian pink granite: the Riviére-a-Pierre
and the Roberval granites.
The Quebec marbles are of two groups, those of the Precambrian
era and those of the Paleozoic era. They are found in the Eastern townships
 and on the southern slope of the Laurentian highlands, and are of
various colours. white. salmon. pink. vellow. violet, cream, green and
rose.

Sandstone of the province includes the Potsdam of Cambrian age,
a white stone; the Sillery sandstone of yellow, green and red colours:
the Niagara sandstone of vellow green: and other varieties of red-brown
and olive-green.
The slate quarries of the province are all situated on the south shore
of the St. Lawrence and belong to the Cambrian and Ordovician formations.
In colour they are red, green, violet, speckled and bluish grey.
The manufacturing of Portland cement is today one of the most
important industries of the province. The four plants in operation in
1927 produced 4,636,751 barrels valued at $5,383,058.
Quick lime to the value of $806,665 was produced in 1927, and 8,660,-360
 tons of sand and gravel valued at $2.145.169 were used.

Peat.—In the settled parts of the province there are 500 square miles
of peat bogs having an average thickness of 8 to 10 feet. This peat con-