Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: AMERICAN AGRICULTURE. CHAPTER I. SOILS. Soils are those portions of the earth's surface, which contain a mixture of mineral and vegetable or animal substances, in such proportions as adapt them to the support of vegetation. Rocks are the original basis of all soils, which by the convulsions of nature, or the less violent but long continued and equally efficient action of air, moisture and frost, have been broken into fragments more or less minute. There are various gradations of these changes. The Texture Ok Soils.— Some rocks exist in large boulders or rounded stones, that thickly overspread the surface and mingle themselves with the earth beneath it, giving to it the name of a rocky soil. The smaller sizes but equal prevalence of the same materials, give to the surface where they abound, the character of a stony soil. A third and more minute division is called a gravelly soil; a fourth is a sandy soil; a fifth constitutes a loam ; and a sixth, in which the particles of earth are reduced to their greatest fineness, is known under the name of a clay soil. The two first mentioned, are not properly distinct soils, as the only support of any profitable vegetation, is to be found in the finer earth in which the rocks and stones are embedded. In frequent instances, they materially benefit the crops, in the influence produced by the shade, moisture, and protection from winds, afforded by them; and by the gradual decomposition of such as contain lime, potash and other fertilising materials, they contribute to the support of the soil. This last effect is aided by the apparently worthless vegetable life which they yield to the living mosses that cling to their sides and everywhere penetrate their fissures, thus imperceptibly corroding the solid structures and preparing them for...