SOILS. 91 



a half per cent.* Prof. Hitchcock remarks, that the results of his experiments disclosed the 

 remarkable fact, "that out of one hundred and twenty-five specimens of srils from all parts 

 of the State (Massachusetts), and several of them from limestone tracts, only seven exhibited 

 any effervescence ; and even these, when analyzed, yielded but a small per cent, of carbonate 

 of lime." He also adds, that a similar deficiency of calcareous matter exists, according to E. 

 Ruffin, Esq. in the soils of Virginia ; and the latter author makes a similar statement con- 

 cerning the soils of some of the Western States, even in limestone regions. " I have," says 

 he, " recently examined five of some of the richest soils of Ohio and Illinois ; and although I 

 find calcareous matter in all but one, yet the average quantity is not over two per cent. Hence 

 I apprehend that we shall find a deficiency of carbonate of lime to be quite characteristic of a 

 large part of the soils of this country. This could not always have been the case, especially 

 in limestone regions ;t and hence we learn — what indeed agricultural chemists now generally 

 admit — that in cultivated fields, calcareous matter is gradually changed or consumed ; and 

 hence too we learn what is one of the great desiderata of the soils of Massachusetts."^: 



If the foreign soils, of which the analyses are given above, were artificial ones, as is most 

 probable, and if the statements in regard to our own soils are correct, there can be no doubt that 

 the addition of proportions of carbonate of lime, much larger than have been usually employed 

 here, would be eminently beneficial. This addition may be made either in the form of marl, 

 powdered tufa, or of calcined lime now so generally used in Pennsylvania and New-Jersey. 



In attentively considering the causes of the fertility of the western soils, one or two infe- 

 rences arc forced upon us. The first is, that if this fertility is derived cither entirely or prin- 

 cipally irom the calcareous matters, there must be some peculiarity in the limestones and other 

 forms of carbonate of liiac which are there found. For it is certain that although there are 

 extensive limestone ranges in the northern and southern parts of the State, the sods in their 

 vicinity do not, on tlie whole, possess those characters which so strongly characterize the 

 western soils. I have thought that this difference might arise from the difference in the state 

 of aggregation or division of the various limestones and calcareous matters. It is well known 

 that the fertility of soils depends, in a good degree, upon the ingredients which comprise them 

 being in a state of minute division. Now this condition appears to be more fully attained in 

 those hmestones which belong to the transition or secondary classes, and especially in those 

 which contain a certain proportion of clay. Indeed, the frequent occurrence of calcareous 

 tufa in the western counties seems to be a sufficient evidence of the ease with which the wes- 

 tern limestones are dissolved by water, and consequently of the minute state of division of 

 which its particles are susceptible by ordinary atmospheric agencies. 



On the contrary, those limestones which belong to the primary class possess a highly cry- 



* Geological Survey of Rensselaer County. 



t Lime disappears from soils I)y being changed into a bicarbonate, in which form it is soIul>le. It is remarked by M. De 

 G;isparin, who has written an interesting paper on soils, that the enclosure of la grand Chartreuse, wliicli is lormed of the debris of 

 rnck>* which contain lime, does not now furnish a single particle of this earth. 



X liepori of a Re-examination of the Econamital Geology of Massachusetts, 1838. 



