Skips are sometimes of very large capacity, holding 5, 7, and even 10 tons of ore; such are used, for example, in several shafts at Butte, Montana, in the Lake Superior copper district, and in South Africa.
The iron ores are even more accessible than the famous ones of the Lake Superior region in the United States.
In the forest regions north of the lakes the vegetation on the shores of Lake Erie requires a high winter temperature, while the east and north shores of Lake Superior have a boreal vegetation that shows the summer temperature of this enormous water-stretch to be quite low.
The fishing industry of Lake Superior is important, salmon-trout (Salvelinus namaycush, Walb), ranging from 10 to 50 lb in weight, being gathered from the individual fishermen by steam tenders and shipped by rail to city markets.
Among these were Alexander Henry (1739-1824), who as early as 1760 had visited the site of Milwaukee, and who now obtained a monopoly of the Lake Superior trade, and Jonathan Carver, who in 1766 reached Green Bay on his way to the Mississippi.
Melaconite was formerly largely worked in the Lake Superior region, and is abundant in some of the mines of Tennessee and the Mississippi valley.
The quantity produced from 1845 Cop er the year in which the Lake Superior district became a producer, and in which the total product was only 224,000 lbup to 1908 was 13,106,205,634 lb.
River canal system from Lake Superior to tide water overcomes a difference of about 600 ft., and carries large quantities of grain from the west to Montreal, the head of summer navigation on the Atlantic. These canals have a minimum depth of 14 ft.
This mineral was discovered in the Marquette district along the shore of Lake Superior early in the 18th century, but active operations for mining it did not begin until 1845; in 1877 mining of the same mineral began farther south in the Menominee district, and seven years later farther west along the Wisconsin border in Gogebic county.
Toledo is the port of entry for the Miami customs district and is an important shipping point for the iron and copper ores and lumber from the Lake Superior and Michigan regions, for petroleum, coal, fruit, and grain and clover-seed.