MINERALS 
0 
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 cera- 
mics, 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, necessi- 
tating 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 prov- 
ince. 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 town- 
ships 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-