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310 BITUMINOUS COAL. 



THE BITUMINOUS COAL-FIELDS OF PENNSYLVANIA. 



Great and valuable as are the anthracite deposites 

 of Pennsylvania, her bituminous coal-region is still 

 more extensive and inexhaustible. We have al- 

 ready stated that the great secondary deposite, which 

 extends from the Hudson to the Mississippi, and prob- 

 ably to the Rocky Mountains, is in Pennsylvania 

 limited by the Alleghany Mountains, which appear 

 to form the barrier or dividing line between the an- 

 thracite and bituminous coal-beds, or between the 

 secondary and transition formations. The union or 

 junction of these formations is distinctly marked in 

 the end of the mountain where the west branch of 

 the Susquehanna breaks through it, above Bald 

 Eagle, the latter resting against the former, and 

 forming the basin in which the bituminous coal, in 

 regular and successive strata, is deposited. 



This coal-field, therefore, is confined to the west 

 side of the Alleghany, and is supposed to extend to 

 the centre of the mountain. In the southeast cor- 

 ner of Somerset county, and in the western parts of 

 Bedford and Huntingdon counties, this coal deposite 

 would appear to extend to the southeast of what is 

 there called the Alleghany, and occurs in great 

 abundance on Will's Creek, Jennings Creek, &c, 

 emptying into the Potomac. The bituminous coal- 

 beds vary from one foot to 12 in thickness, but rare- 

 ly exceed six feet. They lie in nearly horizontal 

 strata, with about sufficient dip to free the mines from 

 water ; some hills containing three and four beds, 

 with alternate layers of earth and strata, resting 

 between a firm, smooth slate roof and floor, as 

 shown in the sections above given. Faults are sel- 

 dom met with, as is the case in the anthracite strata, 

 which goes to prove that all this vast extent of sec- 

 ondary rocks was once the bottom of a great lake 

 or sea, which has been drained by the waters of the 

 Mississippi, the St. Lawrence, the Susquehanna, and 



