'1,353, 354, 355 l ] analyse? — origin of soils. 205 



been likewise collected for analysis, viz : from the point where the change takes 

 place (below six inches) to the depth of fifteen to eighteen inches from the sur- 

 face, according to circums.ances. In all cases the depths at which the soils and 

 subsoils have been taken, will be found recorded with the analysis ; every one 

 will therefore be able to judge as to which of the two layers analyzed corres- 

 ponds to the soils and subsoils which his particular practice may have produced. 



353. Soil Analyses. — Tt has often been stated, and urged even by high author- 

 ity against the utility of analyses of soils, that a specimen of a few pounds 

 <»nnot be made to represent correctly the character o! the soil of a whole 

 region, or even of a single field. This difficulty may indeed become a serious 

 one, where the soil has been long in cultivation, so that fundamental differences 

 may have been superinduced in adjoining fields ; and also where the geological 

 formations are very various, the face of the country much broken, and the under- 

 lying rocks contribute immediately and continually, to the formation of the 

 soil ; though even in the latter case, attentive study will generally succeed in 

 reducing the mass of soils to a few principal types (and their intermixtures), 

 recognizable by their physical characters, or position. In Mississippi, most soils 

 are dependent upon continuous deposits extending over considerable areas, 

 within which they are, to a great extent, of a uniform character ; or at least, 

 ;ar;/ uniformly. 



It is often by no means easy to take correctly specimens of soil intended to 

 represent a district of some extent ; it is necessary, in the first instance, to 

 study closely all the general characters, and upon tint study, to base the selec- 

 tion of representative specimens. And I am convinced that by conscientious 

 observance of this method, it is practicable in this State at least, to study the 

 essential features of all the soils entitled to such consideration by the extent of 

 their occurrence, from a limited number of specimens ; and without an approach 

 to anything as extravagant as the analysis of " the soil of every field," as has 

 been thought necessary. 



354. The period during which the soils of Mississippi have been subject to 

 cultivation, has been too short, and the system of cultivation too uniform and 

 simple, to interpose any serious difficulty on the grounds above alluded to. 

 Moreover, the simple history of almost every field, from the time of its clearing 

 to the present, is still fresh in the memory of its occupant; so that, knowing 

 the original character and constitution of the soil, from the investigation of 

 adjoining tracts still uncultivated, we shall not generally be at a loss to conjec- 

 ture the changes it will have experienced by cultivation. For this reason I 

 have thought it best to restrict myself, for the present, to the investigation of 

 tirgin soils — unless in exceptional cases, where some impertant general truth 

 might be expected to be gleaned from the study of cultivated soils ; as for 

 instance, with reference to soils which, through cultivation, have acquired the 

 -habit of rusting cotton. 



The uncultivated lands in this State are still so extensive, that a knowledge 

 of their soils, their intrinsic value and ultimate fitness for cultivation, is of itself 

 mi object of great magnitude, even if we abstract from the information simulta- 

 neously acquired, as to the character and wants of the land already under 

 cultivation. 



355 1 Origin of Soils. — It is but rarely the case, that the materials of which 

 the strata of the more ancient formations are composed, are fit to serve as soils 

 to the plants of the present age. Even those in which we find the proofs of 

 their once having sustained a vigorous vegetation, whose relics they contain, 

 have mostly undergone essential physical and chemical changes, which render 

 them unfit to resume their former office, until they have undergone a process of 

 disintegration, under the influence of the atmospheric agencies. 



Thus, the soils that bore the luxuriant vegetation which has passed down to 

 our epoch in the shape of bituminous coal, have in the course of ages been 

 converted into shales and claystones, often of considerable hardness, which we 



