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COAL about 2,100 square miles; (4) the Northern or Great Plains area, about 88,000 square miles; (5) the Rocky Mountain area, about 37,000 square miles; (6) and (7) Pacific Coast area, about 1,900 square miles.

Anthracite Areas.—Commercially speaking, the anthracite division may be said to consist of Pennsylvania alone, although a small amount of anthracite coal is mined in other States. The original Coal beds of New England have been metamorphosed into graphite and graphitic Coal. This area is confined to eastern Rhode Island, and the counties of Bristol and Plymouth, Mass, The product mined from the beds, which may be more properly called graphite than Coal, requires a considerable degree of heat for combustion, and can be used only with other combustible material or under an intense draught or blast. Its principal use is in the direct manufacture of steel; the entire annual output is but a few thousand tons. There are five recognized principal divisions of the Pennsylvania anthracite region: (1) The Southern or Pottsville field, extending from the Lehigh river, at Mauch Chunk, S. E. to within a few miles of the Susquehanna river, directly W. of Harrisburg. (2) The Western Middle or Mahanoy and Shamokin field, extending from the easternmost headwaters of the Little Schuylkill river to the Susquehanna. These are sometimes grouped together and given the common name of the Schuylkill region. (3) The Eastern Middle or upper Lehigh field, lying between the Lehigh river and Catawissa creek, and mostly situated in Luzerne co. (4) The

Northern or Wyoming and Lackawanna, mostly in Luzerne and Lackawanna cos. (5) The Loyalsock and Mehoopany field is within the area drained by the headwaters of two creeks of that name, 20 or 25 miles N. W. of the W. end of the field last mentioned. The anthracite region of Pennsylvania, as a whole, has a maximum length of about 115 miles, a maximum breadth of about 40 miles; area about 1,700 square miles; but the area underlaid by workable Coal beds is only about 470 square miles.



Bituminous Areas.—The bituminous Coal areas of the United States may for convenience be grouped into seven divisions: the Triassic, the Appalachian, the Northern, the Central, the Western, the Rocky Mountain, and the Pacific Coast areas. The eastern Triassic area is composed chiefly of the Richmond basin, in Virginia, and the Deep River and the Dan River fields, in North Carolina. No extensive mining operations are now carried on in this area. The Appalachian field is immediately W. of the E. border of the Appalachian range, and extends from New York on the N. to Alabama on the S., its direction being N. E. and S. W.; length, about 900 miles; width, from 30 to 180 miles. There are in this region many varieties of bituminous Coal, the best and most productive beds on the whole being those of the Pittsburgh district and of West Virginia. The thickness of the coal measures in different sections varies from 100 to over 3,000 feet. The northern bituminous area is all in central Michigan. The coal here found is not of superior quality, and is used mostly