BITUMINOUS AND ANTHRACITIC. 443 



Iribution, ranging without interruption from the vicinity of the 

 Allegheny mountain, to the country west of the Allegheny river. 

 Having ascertained the positions of a number of these fossil- 

 iferous beds, I am now engaged in investigating their organic 

 remains. The examinations already made, show that these all 

 belong to marine genera, and that the different beds are charac- 

 terized by their peculiar species. Many of these beds of lime- 

 stone have been traced continuously from northern Pennsylvania 

 to the Kenawha, and from the eastern outcrop, near the Allegheny 

 mountain, to their western boundary in Ohio. The marine char- 

 acter of their genera, — Terebratula, Goniotites, Bellerophon, 

 Eno'iniis, &c., sufficiently proves that these rocks were originally 

 deposited beneath the waters of an ocean, while at the same time 

 the increasing purity of the limestones, and the multiplication and 

 expansion of the beds westward, clearly show that the ancient 

 ocean augmented regularly in depth in that direction. This 

 conclusion, it wilt be observed, agi'ees strictly with the results 

 before deduced from the general gradation, visible in the sand- 

 stones and other mechanically formed rocks, which proves that the 

 ancient land was situated towards the east or southeast. If we 

 examine the relations of the two classes of the coal-strata to each 

 other, the land-derived and sea-derived rocks, we perceive that the 

 latter, or the limestones, thicken, going west at the expense of the 

 former. Frequently, two beds approach, and either entu-ely coa- 

 lesce, or remain divided by only a thin, marly shale, formed from 

 the residual, finely subdivided matter, wafted out by the currents, 

 which, further eastward, or nearer the land, deposited the coarser 

 and thicker sandstones and arenaceous slates. While this grada- 

 tion shows itself, new beds of calcareous rock interpolate them- 

 selves in new positions in the series, and many of the sandstones 

 thin aw^ay and cease altogether, so that the whole formation be- 

 comes, by both these changes, more and more oceanic in its type. 

 But the most important result of this mode of tracing the sti-ata, is 

 the evidence we have of the frequent alternation of a tranquil and 

 disturbed condition of the waters. Such an intermission of move- 

 ment and repose will be more fully proved, when I come to 

 describe the phenomena connected \\-ith the coal-seams. It may 



