ON THE ORIGIN OF THE PENNSYLVANIA 

 ANTHRACITE. 1 



Long ago, H. D. Rogers showed that the coal regions of 

 Pennsylvania are divided into rudely longitudinal basins or 

 troughs. In passing over the state northwestwardly, one crosses 

 first the Archean area at the southeast, with its patches of 

 Newark or Triassic ; then the Great Valley, extending almost 

 unbroken from the Hudson river to Alabama, and showing only 

 Cambrian and Silurian with occasional patches of Devonian and 

 Lower Carboniferous. Crossing the irregular northerly or north- 

 westerly boundary of the valley, he reaches what, for the pur- 

 pose of this discussion, may be termed the Anthracite Strip, 

 which extends to the Alleghanies ; this contains the Cumberland 

 coal field of West Virginia and Maryland, the Broad Top field 

 of southern Pennsylvania, and, still further northeast, the 

 Southern, Middle and Northern Anthracite fields. The Bitu- 

 minous coal basins, of which Rogers recognized six, are beyond 

 the Alleghanies ; the first, between the Alleghanies and Laurel 

 Hill, is well defined near the Maryland line, but becomes less so 

 northward, though it can be traced without difficulty into New 

 York ; the second, with Chestnut Hill as its westerly boundary, 

 is the Ligonier Valley, which like the last can be followed into 

 New York ; the third, wider than the second, is less defined at 

 the west, as its boundary on that side is an anticline passing 

 but a little way east from Pittsburgh and producing insignificant 

 topographical effects ; the most important portion of the basin, 

 in this connection, is the first sub-basin, known as the Connells- 

 ville coke basin, which follows the westerly foot of Chestnut 

 Hill. The remaining bituminous basins, including the rest of 



'Abstract of a paper read before the Geological Society of America, August, 

 1893. 



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