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It has rather an undulating surface, with an elevation above tide of from twenty to eighty feet; and, being penetrated by several large streams, the bluffs on their margins are cut up into numerous channels. It is Uong these channels, high above the water-line, and along the creeks and inlets subordinate to the great rivers, and back into the interior on the same level, that marl shows itself, of the finest quality and inexhaustible in quantity. It may not, indeed, be obtained on every farm sufficiently near the surface, but few neighborhoods are without it. Such, at least, is the case far down the rivers, until, approaching the extremities of the peninsulas, the country subsides into a vast plain, with a comparatively slight elevation above the water. Here the miocene marl disappears, which leads to the belief that it was washed away by the currents of a former sea. But the eocene strata, over which the miocene lay superimposed, still continue, though at great depths. In boring for water at Norfolk, thirty years ago, as previously referred to, shell marl was first struck at a depth of seventy feet, and there was no change in the stratum for seventy feet more, when the anger broke and the boring was discontinued.
On the eastern shore of Virginia no discovery of marl, as far as we have heard, has been made. But there are numerous banks of oyster shells-Indian banks, as they are called-on the margins of the creeks and inlets, supposed to have been accumulated by the aborigines before the discovery of the country. The shells are in a half decomposed state, and, as they readily disintegrate under the action of the plow, they are extensively used for agricultural purposes. In a district of such extent there are, as may well be supposed, several distinct varieties of marl, the most prominent of which may be described under the following classification:
1. Blue marl. This is the kind that most abounds in the upper or western part of the district. It derives its appellation from the compact blue clay in which the shells are deposited, and by a stratum of which usually four or five feet in thickness, but destitute of fossil remains, con. taining only "casts "—the beds are covered. This covering has to be removed before the marl can be rendered accessible. In favorable localities, for the beds are high above the water, a natural drainage of the pits may be readily effected; but, where the ground does not admit of this, the water must be kept down by pumping. The accumulation is seldom so great, however, as to render this a laborious operation, or to interfere materially with the working of the pits. The marl is raised by a sweep or other simple machinery, or, in places where the deposits are shallow, it may be cast out on the banks by hand. When first excavated it is very heavy, and the hauling to the fields is quite laborious; but planters who are prosperous collect a large supply on the banks of the pits, enough to suffice for the operations of a whole season. In the course of a few months the moisture is drained off from the mass, and the clay also loses much of its adhesion. It is, therefore, in a better condition to be hauled on the land, while the burden of hauling is materially lightened. This variety of marl is not so rich in calcareous matter as some others, containing, perhaps, on an average, not more than fifty per cent. of carbonate of lime; but the clay which accompanies it renders it highly useful in its application to arenaceous soils. The coloring matter of the clay is believed to be derived from the presence of minute particles of greensand, which, of itself, is a valuable ingredient in calcareous manures. The blue marl also contains crystals of gypsum, sometimes very numerous.
And here, though perhaps not strictly in place, it may be well to
describe the mode of transportation to the fields, and the usual quantity applied to the land, which is equally applicable to every variety of marl. Assuming an acre to contain, in round numbers, five thousand square yards, the field is marked off with a plow into spaces of ten yards each way, thus making fifty spaces to the acre. In the middle of each space five bushels are dropped. The boundaries being defined, it is easy to distribute with uniformity, and at any desired rate. Carts made expressly for the purpose, and of a capacity of five bushels, drawn by a single horse or mule, being provided, the work of removal goes bravely and systematically on; and with good, active drivers and sufficient teams, a large surface may be marled during periods of leisure.
This is marling at the rate of two hundred and fifty bushels to the acre, which is considered an ample dressing for any land not in a course of, amelioration. On sterile lands, where there is little or no vegetation, it may be too much; and the effect would be to “marl-burn” the soil. But any land, however exhausted, may be improved by the addition of vegetable matter, such as woods litter, pine beards, &c. In places where the land has been thrown out of cultivation, and the old field pine taken possession, a large quantity of suitable material is cheaply and conveniently supplied by felling the growth, then lopping off the branches, and leaving the whole for a couple of years to decay. The marl should be previously spread over the surface that it may have the benefit of a more perfect disintegration by exposure to the air, though it may be done with nearly as good effect afterwards. In preparing for a crop, as much of the decayed vegetation should be turned in as the plow will cover. A great deal of land has, in this way, been restored from poverty to fertility.
When the shells are first taken from their beds they are in their natural shape, and possess a greater or less degree of solidity. But being mixed up with the soil by cultivation, and acted on either by the acids of the soil or the gases of the atmosphere, or both, they soon become thoroughly decomposed, and all visible trace of them is lost after a few years.
2. White marl.-In the peninsula formed by the James and the York River, and in several of the counties north of the York, are extensive beds of white, or pulverulent marl, very rich in calcareous matter; some specimens containing as much as ninety-five per cent., and generally not less than seventy-five or eighty per cent. of carbonate of lime. In these beds the shells are rarely found entire, and the condition of the fragments is such as to render it difficult to recognize the species of fossil to which they belonged. The marl presents an appearance not unlike an impure chalk. In places, however, it is mixed with a large proportion of white clay and sand, so nearly the same color as to make it difficult to distinguish between them without the application of chemical tests.
3. Greensand marl.-This abounds in the vicinity of the Pamunkey River, in the counties of Hanover and New Kent, and is perhaps the most beneficial in its action on the soil of all the varieties of fossil deposits. Besides carbonate of lime it contains potash, phosphorus, and not unfrequently ammonia. When the agriculture of Virginia was in a flourishing condition, the evidences of improvement were particularly conspicuous in that part of the State where this kind of marl is found.
4. Ferruginous marl.-In some localities the shells are deposited in a yellow or ochreous clay, which, doubtless, derives its color from the proximity of ferruginous matter. The beds in some cases are not more difficult of excavation than those of the blue marl, and the effect on the land
is very much the same. But in other localities they have become indurated and are broken up, not without considerable labor. In its texture this marl sometimes bears a resemblance to a secondary limestone, bat, in the opinion of Professor Rogers, it is properly a tertiary limestone. It is found in fragmentary masses along the cliffs of York River on the southern bank, and particularly abounds in the neighborhood of Yorktown. It shows itself above the water-mark, and in precipitous places the surface has been scooped out by the action of the weather, assisted perhaps by artificial agencies. At Yorktown, for instance, there is an excavation, known by the name of Cornwallis's Cave, which tradition represents as having afforded a refuge to the commander of the British forces, at the time of the memorable siege of that place. This rock was used to some extent in colonial times as a building material, but it has not been found to possess the requisite solidity. It contains a large percentage of carbonate of lime, and might, therefore, be converted, by burning, into a valuable agricultural lime. . A specimen of the cliff at York, according to an analysis by Professor Rogers, yielded 87 per cent. of calcareous carbonate; and, computing the quantity of caustic lime corresponding to this, he estimated that a hundred pounds of the shell rock would yield 48.7 pounds of strong lime. We have no knowledge of its. having been burned, but from the abundance of fuel in the vicinity it might, without doubt, be converted into a lime useful both for agricuitural and building purposes. The use of marl was seriously ibterrupted, not to say suspended, by the war, nor has it since been resumed to any great extent. But it is beginning now to come in request again, owing more perhaps to the increasing cultivation of peanuts than to any other cause. This crop will only come to perfection on highly calcareous soils, as otherwise the pods, however luxuriant may be the growth of vines, do not fill. According to present indication the peanut will soon becoine the leading crop in Eastern Virginia. From the great number of persons intending to engage in its culture during the coming season, the presumption is reasonable that the use of marl will receive a fresh stimulus, such as has not been witnessed for the last ten years.
Owing to its great weight, it has not been found profitable to transport marl beyond short distances. The white variety, being the richest and less encumbered with clay, has been lightered from one locality and even from one county to another. This was when its use first excited a general interest. Subsequently, however, it was found more economical to those who had no marl deposits on their estates to purchase what was generally known as agricultural lime, vast quantities of which came in the course of time to be taken by farmers living on the margins of the navigable streams, at whose landings it was delivered in bulk. A regular trade was kept up, for instarce, between the James River and the Hudson, farmers usually paying by the cargo from seven to eight cents a bushel in its powdered state. Since the war, very little of this traffic has been going on, for which two reasons may be assigned: first, that farmers are not yet in a situation to make large investments for the progressive improvement of their estates, and second, shell lime is furnished in sufficient quantity to meet the present demand. This is supplied chiefly from Norfolk, where oyster shells accumulate in immense quantities, and is thence distributed to the inland towns, and to such interior portions of the country as are rendered accessible by lines of railway. This also goes under the general name of agricultural lime. It is the purest form in which lime can be obtained, and is sold at the kilns either by measure or weight, say twelve and a half cents a bushel or five dollars a ton. This would make the first cost reasonable enough, but it cannot be less than doubled after adding the expenses of transportation to a distance. But though possessing a larger percentage of calcareous matter than stone lime, yet nothing of the kind ever acted better on our soils than what was formerly brought from the North River, being, with the exception of sand, free from all extraneous ingredients, such as magnesia, which is found in so large proportion in the Washington lime, rendering it oftentimes hurtful instead of beneficial to the land. Whenever the lands on our river borders shall be brought again into extensive cultivation, the North River lime will doubtless come into as great request as formerly.
It would be doing injustice to the name of a distinguished agriculturist and a man of genius to withhold in this connection a reference to the labors and experiments of the late Edmund Ruffin. His fame is, in fact, indissolubly associated with this subject, for he was the pioneer in the work, devoting for years a mind of extraordinary activity to efforts, both by example and precept, directing public interest in this channel of improvement. A small number of experiments had been made in marling in James City County, as early as 1816, or perhaps earlier, but without being conducted with any intelligent purpose. In ignorance of these, however, Mr. Ruffin made his first experiment in 1818, to the trial of which he was led altogether by theoretical views and by reasoning on the supposed constitution of the soil, as well as the known constitution of the manure. This was on his farm at Coggin's Point, on James Rivar, in the county of Prince George. It extended over an area of about fif. teen acres, but by 1821 the area was increased to eighty acres, and was subsequently continued, until within a few years all the arable land on the farm, say six hundred acres, was thoroughly marled. The result was marvelous, and soon had the effect of stimulating others to engage in the work, until the practice of marling became general among intelligent farmers throughout tide-water Virginia. In all cases wherein any thing like an ameliorating rotation was followed, the crops were quadrupled and the land put into a course of permanent improvement. Proverbially slow as agricultural progress has ever been, yet in the course of forty years, from a very small beginning, a vast revolution was effected, and all through the agency of one man of comprehensive views and untiring energy, whose services in a noble pursuit entitle him to rank as a public benefactor.
Mr. Ruffin's writings on the subject of marl were quite voluminous. For ten years he conducted the Farmers' Register, an agricultural journal, issued monthly at Petersburg from 1833 to 1843, in which the subject of marl occupied a prominent place. But his fame as a writer is chiefly built on his Essay on Calcareous danures, an octavo volume of three hundred pages, which took position as a standard work immediately on its publication.
THE LIMESTONE REGIOX.
Limostones occupy the valley of Virginia throughout its length and breadth. Some of them are of great purity and yield limes equal to any from the north. Some, too, when burned and ground, yield admirable hydraulic cements. These last, however, would not make limes suited to agricultural purposes. Limestones also occur in several places west of the great valley. The Warm Spring Valley is a limestone formation, and large areas in Highland County are covered with it; wbile still fur. ther Test, in what are now the border counties of West Virginia, lime
stones, the same that make Kentucky so great a grazing country, abound almost everywhere, and impart to this whole section its distinctive feature as one of the finest grazing countries in the world.
It would seem, from all we can gather, that very little lime has been used in the valley as a fertilizer. But it does not follow from this that applications of lime to limestone lands are not beneficial. On the contrary, the almost universal use of lime in Lancaster and other limestone counties in Pennsylvania, where high farming is the rule rather than the exception, demonstrates its great value in promoting the fertility of the soil. The experience, indeed, of some of our own valley farmers, who have used lime, goes to prove the same thing. East of the Blue Ridge, in what is termed the Piedmont division of the State, a belt of talcose and mica slate, of varying width, traverses the counties of Fauquier, of Culpeper, Orange, Louisa, Albemarle, Buckingham, Nelson, Amherst, Campbell, Pittsylvania, and Franklin, following a direction mainly parallel to the mountain crests, and consequently running northeast and southwest. A line traced on the State map from the mouth of Summerduck Run, on the Rappahanock, through Orange Court House, Gordonsville, Warminster, on the James, to the mouth of Archer's Creek, and prolonged to the southwest into Franklin County, would indicate approximately the position and direction of this belt of talcose rocks, which accompanies the limestone. The limestones occur somewhat irregularly along this line, interrupted or in layers; not continuous, but outcropping at various places where they have been quarried either for building or burning to lime. From a short distance above Scottsville up nearly to Lynchburg the James River meanders through this belt, and consequently we find the limestone exposed at numerous points along the river, and favorably located for quarrying and water transportation. If lime suitable for agricultural purposes can be obtained from it, this calciferous belt, running through a section the soils of which are as a rule deficient in lime, must prove an incalculable blessing to farmers. Various analyses of these limestones, made by Professor Rogers wbile State geologist, demonstrate their value for all the purposes to which lime may be applied. Considerable variation in the constituents are reported in specimens from different localities, some yielding a lime of excellent quality, some being true hydraulic limes, while others contain a considerable proportion of magnesia. How far the presence of this mineral may affect its value for agricultural purposes the writer is not prepared to say. A belt similar to the one described traverses the northwest side of Fauquier and Loudon, lying along the west side of Bull-Run Mountain. At several localities in this belt the limestone has been burned, and is said to have yielded lime of good quality for building purposes, but we have no information that it has been used as a fertilizer.
It is within the recollection of the writer that the owners of limekilns along James River, at its intersection with the belt above described, were at one time ready to make contracts with the farmers living below for the delivery of agricultural lime at their landings on the canal. Only a small quantity, however, was taken, and no valuable result was ever reported. It was believed that the soils near the river did not require it, and thus the use of lime throughout the district, from the Blue Ridge to tide-water, seems to lave made no progress whatever. At the same time the soils are believed to be destitute of any calcareous ingredient, while a portion of them evidently comes under the head of acid ” soils, according to the nomenclature of Mr. Ruffin, as is indicated by the growth of sorrel, broomsedge, huckleberry bushes, old-field pine, and