THE DEEP RIVER COAL-FIELD.
The Deep River coal-field lies principally in Chatham county, North Carolina, and on the Deep River, which is the south branch of Cape Fear River. The coal-area, as far as developed, is limited, and less in proportion than represented in our map,—perhaps not over 60 square miles; but the probability is that the coal exists in a great portion of the formation, which extends from Oxford, in North Carolina, to a point near Cheraw, in South Carolina, a distance of 100 miles or more, while its maximum width is about 10 miles; but the floor on which the coal mca<3urcs rest, and which is so distinct from the gneissic rocks in which the coal-field rests, is very thick. Professor Emmons estimates the floor at 3000 feet in thickness. This floor, or foundation strata, are of recent formation, compared with the gneiss in which it is laid, and evidently has been the wash of higher grounds deposited by water in this deep basin,—too deep, in fact, to admit the growth or formation of coal until this deposition had been made. Though this coal-field may be of nearly the same age as the Richmond coal-field, or of cotemporary existence, and may have been formed in nearly the same manner, the difference in depth of the original basins would effect the difference in stratification which we find here. In the Richmond coal-field we find a medium depth, or that depth most favorable to the production of coal, as stated in Chapter XIII.,—that is, about 1000 feet, or from 500 to 1000 feet. But in the Deep River basin the original depth must have been 5000 feet or more: hence we find that no coal was produced until at least 3000 feet of sand and slate had been brought down from the mountains by the numerous streams and deposited as a floor in this deep basin.
Unlike the Richmond field, this floor is consequently uniform and even, and the coal is stratified in thin seams uniformly through it, instead of existing in thick masses in the depressions and disappearing on the eleva tions; and, though the coal-seams of Deep River are comparatively thin, that field contains as much coal to the acre, in the aggregate, as the Rich mond field. The Deep River coal measures are similar to the Arcadian, except in the absence of limestone.
This great floor formation of the Deep River field is made up of con glomerates and sandstones chiefly. Some of these sandstones are fine grained, and others are coarse, depending on the time of their deposition during periods of quiet or commotion. They are occasionally red, having been changed by heat, apparently, as the coal in the formation above is frequently changed by heat from a bituminous to an anthracite.
On this floor the coal measures proper are deposited. They consist of alternating strata of black, carbonaceous slate, shales, and fossiliferous sand stones, about 1000 feet in thickness, in which five or six seams of coal are stratified, respectively from 6 inches to 6 feet in thickness. Over the coal measures, according to Emmons, there are from 2000 to 3000 feet of barren measures, composed of red conglomerates, red and green shales, slates, &c.
We think there must be some mistake in estimating this enormous thick ness,—which, in the aggregate, makes 7000 feet of sedimentary strata de posited in the basins of Deep River, and 4000 feet as the depth of the Central coal-basin; which is deeper, in all probability, than the'existence of any coal. Should this be the fact, the coal-seams of this field will thin as they descend, and disappear in the deeper portions of the field.
At Egypt, on the Deep River, south of Haywood, the coal has been cut by shaft at a depth of 360 feet. The largest seam appears to be in the upper portion of the measures, and is about 5 feet thick, generally. It is a rich bituminous, cakes, and consequently cokes easily, and is said to be free from sulphur, but produces white iron in the blast-furnace. The lower seams produce a semi-anthracite occasionally; but whether this is peculiar to certain portions of the field, is not yet ascertained. In fact, the develop ments are meagre, and but little, practically, is known concerning the resources of this field.
Iron-ores of several varieties are found in the coal-field and its vicinity. Those in the field are carbonaceous, argillaceous, and sulphurets, and those in the vicinity are red oxides and magnetic. The seams of ore are thin, but frequently rich, and might be put to great advantage in the manufac ture of iron if the coal can be used in the furnace. This, however, has not been fairly tested ; but it is our impression that none of the Southern coal will make good iron in the blast-furnace, and our experience in this matter entitles the opinion to some weight. The ores of North Carolina and Vir ginia are rich and plentiful, and, with pure fuel, produce the very best of iron; but the coal generally is impure, and cannot be used successfully in the blast-furnace. But the Southern coal can be profitably used in the production of iron from those rich ores otherwise than in the blast-furnace, since wrought iron can be economically made by several methods in which the coal and the ore do not come in contact, as described under the con sideration of iron in another portion of this work. No coal exists suitable for use in the blast-furnace south of the anthracite fields and east of the Alleghanies,—including the Broad Top and the Cumberland coals. Attempts were made during the war to use it, but in all cases, as far as we have heard, without success. All the iron produced in the South, with the exception of that made in some portions of Tennessee, Kentucky, and Missouri, or in the region of the true coal-fields of the Appalachian forma tions, has been made with charcoal. A large iron-making establishment, including furnaces and rolling-mill, was erected in Chatham county, North Carolina, but had not fairly got into operation when the war, which it was built to support, proved its destruction. We understand it was destroyed by Sherman's boys, as not required by the United States Government!