III. Monopolios de la riqueza mineral.

distributed, too, productive mines being now in operation in 27 of the States and Territories. Anthracite coal, however, which is by far the best adapted to domestic use, only occurs in a limited area in the State of Pennsylvania; but here the deposit is of phenomenal richness. The total area of the Pennsylvania anthracite field is about 300,000 acres. Of this area nearly 200,000 acres is owned by seven railway corporations. These companies, either directly or through subsidiary companies controlled in the same interest, carry on mining operations, carry the coal to market, and sell it. The following figures³ exhibit the receipts of each of these companies from sales of coal from their mines during the year 1887: