THE THIRD, NORTHERN, OR WYOMING ANTHRACITE COAL-FIELD.
This is the largest of the anthracite basins of Pennsylvania. The latest and, we think, the most reliable computation gives it an area of 198 square miles, or 126,720 acres. Its length is over 50 miles from a point opposite Beach Grove, which is a short distance below Shickshenny, to a point some five or six miles east or northeast of Carbondale. Its maximum breadth is over five miles, and its mean not less than 31, or nearly four miles.
The general form of the field is that of a long, narrow, trough-like basin, deep at its lower or western extremity and shallow at its upper or eastern end. It is not, however, straight, or perfectly parallel along the lines. of its axis, or strike, but has a gradual curve from end to end, in the form of a crescent or slightly-bended bow, curving on a radius of about 50 degrees,—the eastern horn pointing at Carbondale N. 20 degrees E., and the western horn at Shickshenny, S. 20 degrees S. of W. At both extremities the coal measures rise gradually to a point far above water-level On their central depressions, in like manner as they rise along the sides of the basin, but with comparatively low ascending angles. It is therefore emphatically a basin, with a rim of hard and durable conglomerate, ranging from 100 to 300 feet thick.
It contains in an eminent degree all the conditions necessary to the production of coal ; and, judging from present appearances, we might be tempted to state it as an independent formation, having no reference to or cotemporaneous existence with any other coal-field, and without relation to the great Appalachian formation ; but a general knowledge of the cotempo raneous geology, of course, permits no such inferences. There can be no doubt, however, of the fact that the basin in which this coal-field now lies existed as a basin or deep lake, not only when the coal was formed, but long anterior ; and the probability is that but little if any coal was ever formed on the surrounding mountains. Coal was originally formed in basins, and always exists in basins; and wherever the conglomerate pre sents evidence of the existence of a basin, there coal is always found. There are many cases of denudation, but they leave their evidences behind. Basins may be cut through in a hundred places by water, but there are always por tions of the formation left.
Below we present a view of Shickshenny, and on the next page a general illustration of the Wyoming or northern coal-field. It presents at a glance the whole geology and peculiarities of the basin.
The accompanying illustration presents the plan or area of the coal-field ; the form or lay of the coal measures lengthwise, or from east to west, and the form of the intermediate basins, or the cross-sections from north to south.
With the aid of the foregoing description, and the accompanying illustrations, we hope a good general impression of the form and features of the Wyoming Valley and basin may be obtained.
A great portion of the coal of the northern field is accessible by shallow shafting,—perhaps two-thirds of the entire amount. All the coal above or east of Pittston, and fully one-half below, or west, can be obtained within an average shafting depth of 400 to 500 feet, or within 800 feet as a maximum. This may be considered as eminently available, when com pared with many of the European coalfields, or as compared with the greater portion of the deep coals of Schuylkill county.
But little of the Wyoming or Lackawanna coals, however, can be ob tained by drifting above water-level, though much of the coal on either edge of the basin really exists above it. The conformation is such that the coal is not accessible by drifting on the strike of the veins, since they are not often exposed across the axis; the inclination of the covering strata being parallel or on a plane with the coal, and the form of the valley con forms to the shape of the coal-basin beneath. Therefore, the coal which lies above water-level can only be reached by long tunnels or short shafts. There are notable exceptions, however, as may be found at Nanticoke and the western extremity generally, though but little developed; at the old Baltimore mines, and on the property of John T. Everhart, northeast of Pittston, the same facilities exist for mining above water-level. But generally, as we before observed, most of the coals of the northern field are more accessible by shafting than by any other mode. We include slopes, which are but inclining shafts, in the same category; though this mode is only available at a few localities in the vicinity of and below Wilkesbarre.
The accompanying columnar or vertical sections, through the coal measures, at three different points in the basin, vtill enable us to present several interesting subjects in connection with the veins and the measures in a clear and definite form. They show the relative depth of the basin at the points distinguished; the sizes and number of veins; the order of their existence or position, and their identity,—which, we believe, has never before been attempted.