The veins in the Northern coal-field all produce a white-ash coal,—or those which have been worked to the present time. We do not know of a single instance in which the upper or red-ash seams have been operated for the market. We think it probable the upper seams in the Wyoming region are of the red-ash variety; but, though they may be identical with the red-ash veins of the Pottsville district, it does not necessarily follow that they must be red-ash also, since the causes producing the coloring of the ash—the oxide of iron, &c.—are local.
One of the lower beds in the Wyoming region, which we have denomi nated B, but which Rogers and others identify with the Baltimore bed E, produces a red-ash coal from one of its lower benches, which is a dis tinguishing feature of B, wherever found. The large and magnificent Grand Tunnel bed, and the Lee vein at Nanticoke, are identical with B, or the celebrated Buck Mountain. We know there is a diversity of opinion about this matter; but we think the facts are positive.
The Baltimore bed E depreciates in size as it runs west, but preserves its excellence and purity; while the Grand Tunnel vein B depreciates rapidly in both size and character as it spreads east. It is rather a difficult matter to determine whether the Patten or Bennett vein at Plymouth is tit Baltimore or the Grand Tunnel. We have never personally examined the Plymouth district, and cannot speak from experience in regard to this question.
We give on page 181 three sections of the Buck Mountain, Grand Tunnel, or B vein, as operated at the several localities in the western end of the field. It will be found to correspond not only in each locality in the Wyoming region, but also in the Lehigh basins.
This is the lowest workable vein in the anthracite coal-fields. At Nan ticoke its position is clearly defined, as resting on, or nearly on, the con glomerate, but underlaid by the invariable bed A, which is always small and always on or in the conglomerate. At West Nanticoke the same con ditions exist. The Harvey and the Grand Tunnel mines are in this seam; and here, as at Nanticoke, it rests on or near the conglomerate, with only one small seam of three or four feet below it. The Baltimore vein, clearly, cannot be the same, since there are at least four seams beneath it, as shown in every section we have made; and our data are in all cases official, and from the best practical local sources.
The lower benches of B produce a red-ash coal, not only at Nanticoke, but at the Lehigh Buck Mountain mines, and wherever the bed B is operated. It is distinguished almost invariably by a heavy parting slate which divides the vein near its middle. This will be noticed in every section we have given of this seam, except at the New Boston mines, on the Broad Mountain, in Schuylkill county; but even there the character and appearance of the coal are the same.
We think, therefore, that the Grand Tunnel, or Lee's Nanticoke vein, is not identical with the Baltimore bed, and that it probably underlies the Bennett or Patten vein at Plymouth, but in all probability much depre ciated. In no part of the valley do the conditions necessary to the pro duction of coal exist more favorably than in the vicinity of Nanticoke, or between that and Plymouth. The lower veins, therefore, attained a larger size here than at any other part of the valley, or, perhaps, in the anthracite regions ; but whether the succeeding seams were formed in the same proportion does not appear: they have been denuded or carried away by the rush of waters through the Nanticoke defile, which occurred long after the formation of these coal-seams.
We may here remark a general law of those early formations. In all cases where the bastns are comparatively shallow, but not excessively so, and the base-rocks are even and uniformly laid at low angles, the lower beds are large and productive, but the upper ones seldom appear, simply because the shallow depths of the measures do not admit of their formation. The Grand Tunnel bed is laid on a gently inclining surface, which must have existed at no great depth in the basin; when followed below water level, the dimensions and general character of this vein depreciate rapidly, as demonstrated at Lee's Nanticoke mines; and the probability is that this vein will be quite lean and small in the deep basins of this vicinity, as it is further east.
The Baltimore bed was at first worked as an open mine, or quarry, in the vicinity of Wilkesbarre, where it is very thick and productive. The character and purity of its coal cannot be excelled, and are only equalled by some of the Ashland and Lehigh coals from E, or the same vein.
Operations on the Baltimore bed commenced at an early date, and most of the coal sent from the Wilkesbarre district has been obtained from this vein alone: yet but a small amount of its area has been extracted. Few veins have been more productive than this. It is from 18 to 24 feet thick, and, consequently, yields a large amount of coal per acre. The roof, or top rock, is solid and substantial; the amount of overlying surface is not great in the area operated on; while the low angles of dip admit of the coal being worked without much waste, and with great economy. As long as this vein remains productive at moderate depths from the surface, the seams below and above it will remain in comparative idleness, or in an undeveloped condition, though some of them are good, reliable, and pro ductive seams.
The Baltimore or E vein, at Wright's mines, in Newport, or the lower end of the Wyoming Valley, is rather less in size than at Wilkesbarre ; but the coal is excellent. We give the following notes in relation to its thickness.
Before closing our remarks in reference to the beds B and E, we are bound to say there is something inexplicable to our present comprehension in the Plymouth district. It would almost appear that the Baltimore and some underlying vein united there, or below that point, to form the Grand Tunnel bed. We find at the Chauncey mines of the Union Coal Company the Grand Tunnel vein divided by 5 feet of slate, with 9 feet of top coal and 10 feet of bottom coal; while at no great distance we find, at the Sweatland mines of Langdon & Co., a ten-foot upper coal, known as the Cooper, and a 14-foot lower coal, known as the Bennett vein, divined by 30 feet of measures. But, as we before observed, this district is a terra incognita to the writer, and all attempts to gain information from those who ought to know have remained unanswered.