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is associated with nickel. The nickel mines of Ontario, which produce 
more than half the nickel of the world, are all connected with a great 
eruption sheet a mile and a quarter thick, thirty-seven miles long, and 
seventeen miles wide. The deposits all occur at the margin of the sheet in 
depressions beneath it or in offset deposits pushing out into the country rock. 
The nickel eruption, norite on the lower side, merging into micro- 
pegmatite on the upper side, is really a laccolithic sill bent into a synclinal 
shape by the collapse of the Archean rocks beneath when the molten matter 
ascended to its present position. 
3. Iron Deposits of Canada. By Professor W. G. Minter. 
Canada’s iron industry is not yet a large one, but it is making satis- 
factory progress. One centre of the iron-smelting industry is at 
Sydney, B.C., but there are smelting industries in a number of other places. 
The chief productive iron ranges of Ontario are at Michipicoten, at Moose 
Mountain near Sudbury, and at Bessemer in Eastern Ontario. The Lake 
Superior mines have made the United States the leaders in this industry, 
but similar iron ranges are found in Canada from the Lake Superior 
region eastwards to Ungava, and westward to the Great Slave Lake, 
although these have been little explored. As the country is opened up, 
Canada is certain to have an important iron industry. 
4. Placer Gold Mining in Canada. By J. B. Tyrrety, M.A. 
Placer mining in America may be said to have had its origin in 
California in 1848. After having engaged in mining for a few years, many 
of the thrifty and successful miners settled down in their adopted State 
and lent their time and fortunes to its development. But Canada profited 
most from those who were less successful, for many of the disappointed 
California prospectors wandered to British Columbia, where they discovered 
the gold-bearing gravels of White Horse Creek in East Kootenay, and 
of Williams and other Creeks in Cariboo, from which gold to the value 
of £14,000,000 was extracted. 
The Cariboo diggings, after being abandoned by the individual miners, 
were taken over by mining companies that attempted to work them by 
hydraulic processes. But the supply of water was insufficient. Large 
reservoirs were built one after the other, and these proved to be simply 
evaporating basins, so that as the areas of the reservoirs were increased, 
the quantity of available water diminished. 
Other prospectors crossed the Rocky Mountains into Alberta and dis- 
covered fine gold in the sands of the Saskatchewan and Peace Rivers. 
As these streams derive their supplies of gold from the soft and slightly 
auriferous Laramie (Hocene) sandstones which form their banks, they 
may be regarded as permanent sources of a small annual supply of that 
metal. 
But the great region between the Rocky Mountains on the east and the 
Cascade Mountains on the west appealed most strongly to the prospectors, 
so they kept moving north-westward, first discovering the Cassiar country, 
and finally, in 1896, the Klondike, from which latter camp gold to the 
value of about £25,000,000 has been extracted. The richest pockets in this 
region have now been exhausted, and the individual miners have mostly 
keen replaced by companies that have begun to extract the remaining gold 
from the lower grade gravels with dredges and hydraulic plants. It is to 
be hoped that these companies will succeed better than those that attempted 
to operate in the Cariboo country. 
