File:Allegany coal basin.jpg

The Cumberland coal-region in Maryland belongs to the Greay Alleghany coal-field. Most of the coal-mines in Maryland [as of 1866] are in the Frostburg, Maryland basin known as the Georges Creek Valley. The Cumberland coal-region, or that portion of the Alleghany coal-field in the Frostburg basin, is about 5 miles wide by 30 miles long, or covers an area of 150 square miles: some accounts make it 180 square miles. The portion of the Maryland coal lying between the Savage Mountains and Negro Mountain, and extending across the Stte in a narrow though, as represented by the figure, comtains about 130 quare miles; and the trough or basin on the Youghiogheny, between Negro Mountain and Laurel Hill, or Briary Mountain, contains about 130 square miles; makein the total area of the Allegany coal-field in Maryland about 550 square miles. The Frostburg basin extends on the northeast into Pennsylvania, and on the southwest into Virginia. The distance through Maryland is about 20 miles. It is convex-shaped, or an oblong basin, rising slowly to the north and south, along the strike of the seams, from a common centre near the mouth of Georges Creek, or its confluence with the Potomac, and more rapidly east and west, or to the outcrops of the seams, on the face of the Dans Mountain and Great Savage Mountain. The rise of Georges Creek from its mouth, near Piedmont, West Virginia to its source, near Frostburg, Maryland is 1100 feet. But the rise of the seams which strike in the same direction is not proportionate to the rise of the streams. ^[1]

Samel Harries, "Coal, Iron, and Oil", B. Bannan 1866 (copyright expired), Full Text Online, page 333.

See below.