1S36.] 



FARMERS' REGISTER. 



211 



exhaust the soil in a sensible degree; in the other, 

 without manure they will scarcely grow at all. 

 To make this soil productive, ihcrc is absolute 

 need of a stimulant to dcvclope its vegetable pow- 

 ers, and the efTect of the (alimentary) manure 

 consists as much in stimulating tiic soil and the 

 vegetable organs, as in supplying them \vil!i nu- 

 tritive juices. When an equal quantity ofmanure 

 is given to these two soils, so different in their na- 

 tures, that its effect on the calcareous soil is per- 

 haps twice as great as on the silicco-argiiaccous 

 soil; whence we should naturally conclude that the 

 fi^culty of imbibing, the principles of vegetation 

 from the atmosphere, is much more powerful in 

 the calcareous soils, and the vegetables it produces, 

 than in the argilo-siliceous soil, and it is thai 

 which constitutes their greatest dili'erence. 



XXIV. But this important ficulty, which na- 

 ture seems to have refused to this soil in its forma- 

 tion, man, by a happy compensation, may giv^c to 

 il, with all tiie properties and all the advantages i 

 which distinguish calcareous soils. If he covers I 

 this soil with marl, if he applies to its surface a | 

 certain quantity of lime, or sprinkles it with ashes, 

 or even confines himself to burning its surface, , 

 then the nature of the soil is changed; an unusual i 

 fertility appears — (alimentary) manures act upon , 

 it with more effect, and the soil receives that hap- 

 py impulse which, Avhen it is extended over the 

 whole surface of a country, changes its entire as- 

 pect, and produces in it agiicultural wealth, the 

 assured source of prosperity, strength and popula- 

 tion. Lime, and the substances which contain it, 

 would then be a very powerful means of vegeta- 

 tion on a soil which does not contain them; spread 

 so as to form scarcely a two-liundredih part of the 

 •cultivated stratum, it increases ^vith the ordinary 

 quantity of manure all the productions more than 

 50 per cent., during a period of more than twelve 

 years. The calcareous particles which il furnishes 

 to the vegetable texture, are not a millionth part 

 of the product itself, since lime does not form a 

 moiety of the weight of the vegetables reduced to 

 ashes. This surplus of production which is not 

 furnished at the expense of the soil, (since at the 

 end of tv/elve years it v\'ill still be richer than be- 

 fore the application of the alunentary manure,) 

 and which does not come from the very small por- 

 tions of the substance of the lime, (which docs not 

 form a millionth of the production,) comes then 

 from the atmosphere. The soil and the vegeta- 

 bles which it supports, have then received from 

 the lime, and from its mixture with the vegetable 

 stratum, the faculty of imbibing from the great 

 reservoir of vegetable elements, carbon, azote, 

 oxvijen and hydrogen. 



We shall not now expatiate fiu-ther on the sub- 

 ject of improvements by calcareous substances: 

 they demand a loufjer and more particular expla- 

 nation which will find another occasion.* 



XXV. Let us return to our principal subject. 

 As we have said elsewhere, by a fortunate and 

 beneficent harmony, the formation on which the 

 argilo-siliceous soil rests is calcareous, and con- 

 tains marl in great abundance; there is not within 

 our knowledge an argilo-silicious plateau in which 

 marl has not been found at a greater or less depth; 



* And which has been already presented to the 

 readers of the Farmers' Register in Vol. Til. in M. 

 Piivis' essays on lime and marl. — En. 



! generally, it is found where the ridge or table land 

 1 ends on reaching the alluvions of tlie basins, and 

 . in the inflexions of the soil where the waters have 

 I carried ofTa considerable part of the deposite.t 

 j On a great portion of the surlace of the terres d 

 bois, terres ehjirei of Belgium, and of the Dcpart- 

 I inent of the North, marl has been found. In Pi- 

 cardy, it is brought up from some depth; on the 

 tablelands of the three Departments of ancient 

 Normandy, it is sought at a depth of 100 ftjet, 

 even of 200 i'c&t from the surface; Puisaye obtains 

 it on the surface (in out-croppings) and Dauphiny 

 at a slight depth. 



Our great plateau which extends into three Dc- 

 i partments, shows it on the borders and in the ba- 

 i sins of the streams which water them. On most 

 I of the great plateaux wlu('h border on the Loire, 

 and which form a great part of the soil of a dozen 

 S^epartments, marl is frequently met with, and is 

 i in many places successfully employed. The boul- 

 i bins of Toulouse have it also, and make use of it 

 I with great advantage. 



I Finally the plateau which forms the Gafinais 

 and Soloirne, which declines partly to the Seine 

 I and partly to the Loire, rests every '(vhere upon cal- 

 careous deposiles. Marl is found either on the edge 

 of the plateau, or at a little depth in its first por- 

 tions, or finally in the basins of the streams which 

 water them. We may then regard it as certain, 

 that generally, there prevail under the argilo-si- 

 licious deposite a calcareous formation and de- 

 posites of marl, which when brought out upon the 

 surlace may give it a fertility almost equal to that 

 of the most favored soils. 



Nevertheless, sufficiently numeious observations 

 have often shown me a stratum, not calcareous, but 

 resembling, in its exterior characters, the earthy 

 marl, on the nature of which chemical tests alone 

 have been able to undeceive me. This stratum, 

 which is nothing else than what we have distin- 

 guished by the name of plastic clay, is met with 

 It-om time to time on the table lands, and in the spots 

 where we may expect to find marl; but it is still 

 more frequently found at the bottom of brooks, where 

 it serves as a sub-soil to poor meadows. I have 

 found it sometimes in cysts (sacs) with marl, and 

 by its side. I have never met with it upon the 

 marl, but often below it: the plastic clay should 

 then be subordinate to the calcareous stratum, as 

 this last is to the argilo-silicious stratum, and we 

 should hence conclude that where the plastic clay 

 is met with, the calcareous stratum is wanting — 

 has been carried off — and consequently marl will 

 not be found. 



fEven in this important respect, the resemblance 

 holds between the argilo-silicious lands of the author, 

 and the "acid" ridge lands of lower Virginia, and pro- 

 bably of Maryland and North Carolina. Though not 

 the marl described by M. Pnvis, a calcareous stratum 

 of fossil shells underlies, at various depths, nearly the 

 whole of this vast region: and though it has as yet been 

 reached for use only where its out-croppings show at 

 the surface, in future times, when the value of this 

 improvement will be properly understood, this bed 

 will be found and obtained by deep pits, almost in every 

 neighborhood, and for the use of large spaces which 

 are now considered destitute of, and entirely debarred 

 from this manure. — Er. 



