396 THE SOUTHERN PLANTER. 



tion, the soil is general!}' productive ; but 

 where the sandstones prevail, as they do ex- 

 tensively in the mountainous parts of West- 

 ern Virginia, lying along the eastern side 

 of the coal regions, the soil is generally 

 poor. 



In the Carboniferous or coal formation, 

 many of the slates and sandstones form 

 soils of no great value ; but belts of lime- 

 stone and calcareous shale sometimes give 

 corresponding belts of good soil. We find 

 an interesting example of such limestone 

 soils in the belt which runs through G-reen- 

 brier and adjoining counties, and around 

 the base of the coal-bearing strata in our 

 great Western coal field. The accumula- 

 tions of detritus in the valleys, and along 

 the streams, also afford good soils. Where 

 the slaty lands of this, or any other forma- 

 tion, lie in a horizontal position, thjfey are 

 impervious to water, and lience are cold and 

 wet. These must generally be drained 

 before they can be successfully cultivated. 



What has been said of the influence of 

 the various kinds of rock upon the soils 

 overlying the formations already mentioned, 

 will lead us to the general conclusion that 

 the quality of the land upon all the higher 

 formations, must be as variable as the char- 

 acter of the rocks themselves. The sand- 

 stones generally give light, infertile soils, 

 while those produced slates and shales are 

 better ; and, when free from bituminous 

 matter, and supplied with lime, are often 

 very productive. 



Some ©f the formations have the elements 

 of their own improvement treasured up 

 within themselves. A striking example of 

 this is seen in the marl beds, so abundantly 

 deposited in the tertiary strata lying along 

 our eastern coast. Many farms in the tide- 

 water sections of Virginia, Maryland, and 

 other States, have been most successfully 

 and profitably reclaimed from almost hope- 

 less exhaustion, by the judicious application 

 of these tertiary marls. Besides the marl 

 proper, little mineral nodules of a dark col- 

 our are found in the same beds, or in con- 

 tiguous deposits; and on being analyzed, 

 they are found to contain a large per cent, 

 of phosphate of lime. Prof. Johnston, of 

 England, says : " This crag [a tertiary de- 

 posit] is chiefly interesting to the agricul- 

 turist from its containing hard, rounded, 

 flinty nodules — often spoken of as coprolites 

 — in which as much as 50 per cent, of 

 phosphate of lime (bone earth) has been 



[July 



found. These nodules are scattered through 

 the body of the marls, and through the sub- 

 soils of the fields far inland ; and are col- 

 lected for sale to the manufacturers of su- 

 per-phosphate of lime, and other artificial 

 manures." (^Ag. Chem. p. 94.) Similar 

 black pebbles occur in the Olive Earths 

 and Marls of the tertiary strata of Eastern 

 Virginia. Mr. Ruffin, the venerable and 

 distinguished President of the Virginia 

 State Agricultural Society, first brought 

 these to the notice of Prof. Grilham, of the 

 Military Institute, by whom some speci- 

 mens were analyzed. After being crush- 

 ed and thoroughly mixed, they were found 

 to contain 56 per cent, of phosphate of 

 lime !" — (^Southern Planter, Dec. 1858.) 



The experience of the agricultural world 

 has established a conclusion of great prac- 

 tical importance in the selection of lands 

 for tillage. It is this — that, among the up- 

 land soils, none are so uniformhj and per- 

 manently frtile, as those formed from cal- 

 careous rochs. And next to these, the soils 

 from the lime-hearing trap-rochs and syenites 

 occupy the first place. Alluvial and drift 

 soils, of course, are exceptions. 



STRUCTURE OF THE SOIL. 



In examining any soil which has been 

 left undisturbed to pass through its natural 

 stages of formation, we find the surface por- 

 tions differing considerably from those 

 nearer the original rocks. They differ not 

 simply in appearance, but also in composi- 

 tion, and consequently in fertility. 



It is both interesting and instructive to 

 trace out the various changes which have 

 taken place, in reducing the original rocks 

 of the earth to the condition of arable soil. 

 Let us take, for example, a calcareous for- 

 mation, made up of limestones and calca- 

 reous shales, which have just been upheaved 

 by volcanic agency, and for the first time 

 exposed to the disintegrating influence of 

 the weather. The shales are rapidly 

 crumbled down to the condition of clay, 

 from which the rain gradually dissolves out 

 much of the carbonate of lime, carrying it 

 off to form "limestone springs." The more 

 solid rocks are worn down more slowly, but 

 not less surely, by the operation of the same 

 causes. In this way a soil is gradually 

 formed, supplied with all the mineral, in- 

 gredients of the rocks. But such a soil, 

 produced by such a process alone, would 

 still lack one important class of its elements 



