The local name for the Iredell clay loam is "wax land," from the waxy nature of the subsoil, or "black-oak land," from the timber growth. A few small, isolated areas of this soil occur in the intermediate valley of the Catoctin Belt, and here the texture is much the same as that described above; but the soil usually consists of from 6 to 10 inches of a drab or brown loam, underlain by a heavy mottled yellow and drab silty clay. This phase has few stones on the surface or in the soil. The local names for this phase are "cold, sour land" and "white clay."
The greater part of the Iredell clay loam occurs in the southern or southeastern corner of the County and occupies one large, irregular-shaped but generally connected area, extending from Leesburg, in a southeasterly and southerly direction along Goose Creek to the southern boundary of the County, the most typical development of the soil being at Waxpool. The phase already described occurs in small, disconnected areas, usually quite far apart, the general relative direction of these areas being northeast and southwest. They all lie in the intermediate valley of the Catoctin Belt, and are usually near the foot of the Blue Ridge or Short Hills. The most typical development of this phase occurs just southeast of Bluemont.
Where rolling and sloping the surface drainage is good, the water passing rapidly from the surface into the numerous small streams flowing into Goose Creek, which is the main drainage way of this type. In the low, flat lands the water stands or flows very slowly from the surface. Owing to the impervious nature of the clay subsoil, underdrainage is very slow, and the land is often cold and sour.
Corn, wheat, and grass are the principal crops grown on this soil type, the average yields per acre being as follows: Corn, from 20 to 40 bushels; wheat, from 8 to 15 bushels; and grass, from 1-1/2 to 2-1/2 tons. Apples do fairly well.
The greater part of the type is tilled, while the uncultivated areas are used for pasturage and wood lots, the forest growth being black oak. In dry seasons, where the soil covering is not deep, the land bakes and cracks, and in this condition it can not be cultivated. In wet seasons the soil becomes too wet and sticky to work.
The Penn loam consists of from 8 to 12 inches of a dark, Indian-red loam, underlain by a heavier loam of the same color. This peculiar red color is distinctive of the formation wherever found, and, consequently, the type is one easily recognized. The texture of the type is very uniform, with the exception of a few small areas where the subsoil is a clay loam. The soil is locally termed "red-rock land," on account of the numerous small red sandstone fragments which occur in the soil and subsoil in quantities varying from 5 to 20 per cent of the soil mass. The soil is free from large stones or other obstructions to cultivation.
This type occurs in several large, irregular areas on the Newark formation of the Piedmont Plateau in the eastern part of the County. The areas have a general northeast and southwest trend. A few small areas occur in close proximity to the larger ones. One of the larger areas is situated just south of Leesburg, while another occurs east of Lucketts.
The topography consists of a gently rolling to nearly level plain, and there are no steep slopes or rough areas. Drainage in this type is excellent, the easy slopes allowing a gradual flow of water from the surface without undue erosion, except with very heavy rains on the steeper slopes. The loamy subsoil allows a ready but not too rapid percolation of surplus soil moisture, and never gets soggy or in a cold, sour condition. Numerous small streams extend throughout the area of this type, allowing a rapid removal of all surplus water into the Potomac River, the chief drainageway of the County. Along these streams, which in all cases have cut out beds some 10 to 30 feet below the surrounding plain, the slopes are gradual.
The original growth on the Penn loam was a forest of oak, hickory, and walnut, but at the present time nearly all of the type is cleared and farmed. The soil is not naturally very productive, but is prized on account of its great susceptibility to improvement, its quick responsiveness to fertilization, and its easy cultivation and management. The surface is smooth and regular, and the absence of stones, together with the loamy texture of the soil, makes it easy to maintain good tilth. Any addition of fertilizers or lime is immediately effective, and by judicious management the type may be kept in a high state of productiveness. Many fine farms with good buildings are to be seen on this type. The crops grown are corn, wheat, grass, clover, apples, and small fruits. Grazing, stock raising, and dairying are practiced to some extent. The land yields from 40 to 60 bushels of corn, from 10 to 15 or more bushels of wheat, and from 1 to 2 tons of hay per acre.