42 CALCAREOUS MANURES— THEORY. 



portions. It should be remarked that all these were selected from situations 

 which, from their proximity to calcareous rock, or exposure to calcareous 

 waters, were supposed most likely to present highly calcareous soils. If 

 five hundred specimens had been taken, without choice, even from what are 

 commonly called lime-stone soils, (merely because they are not very distant 

 from lime-stone rock, or springs of lime-stone water,) the analysis of that 

 whole number would be less likely to show calcareous earth, than the fore- 

 going short list. I therefore feel justified, from my own few examinations, 

 and unsupported by any other authority, to pronounce that calcareous 

 earth will very rarely be found in any soils between the falls of our rivers 

 and the navigable western waters. In a few specimens of some of the best 

 soils from the borders of the Mississippi and its tributary rivers, I have 

 since found calcareous earth present in all— but in very small proportions, 

 and in no case exceeding two per cent. 



When the total deficiency of carbonate of lime, in nearly all the soils of 

 Virginia, was first asserted, as above, in the earliest publication of this 

 essay, (1821^ in American Farmer, vol. in.,) the proposition was so entirely 

 new, and so opposed to all inferences from authority then existing, that 

 it was indispensably necessary to adduce my facts, as is done above, to 

 sustain the otherwise unsustained doctrine. And such support, for the 

 same reason, continued to be wanting through the two next editions. Now 

 (in 1842) the case is altogether different. The fact of the absence of car- 

 bonate of lime, as generally as I had assumed, through the eastern or 

 seaward slope of the United States, and especially in New England, has 

 been confirmed by all the analyses of soils which have been since made 

 by Professor Hitchcock and other accurate scientific investigators ; and the 

 proposition, however untenable or incredible it might have been deemed 

 before, is now universally admitted, and indeed is placed beyond question 

 or doubt, as an important feature in the chemical constitution of soils. 



The only soils of considerable extent of surface which, from the speci- 

 mens that I have examined, appear to be highly calcareous, and to agree in 

 that respect with many European soils, are from the prairies, those lands 

 of the south-west which, whether rich or poor, are remarkable for being de- 

 stitute of trees, and covered with grass, so as to form natural meadows. 

 The examinations were made but recently, (in 1834,) and are reported 

 because presenting striking exceptions to the general constitution of soils 

 in this country. 



20. Prairie soil of the most productive kind in Alabama ; a black clay, 

 with very little sand, yet so far from being stiff, that it becomes too light 

 by cultivation. This kind of land is stated by the friend to whom I am in- 

 debted for the specimens, to " produce corn and oats most luxuriantly— and 

 also cotton for two or three years ; but after that time cotton is subject to 

 the rust, probably from the then open state of the soil, which by cultivation 

 has by that time become as light and as soft as a bank of ashes." One 

 hundred grains of the specimen contained eight of carbonate of lime. All 

 this prairie land in Alabama lies on a substratum of what is there called . 

 "rotten lime-stone," (specimens of which contained seventy-two to eighty- 

 two per cent, of lime,) and which rises to the surface sometimes, forming 

 the "bald prairies," a sample of the soil of which (21) contained fifty-nine 

 per cent, of carbonate of lime. This was described as "comparatively 

 poor — neither trees nor bushes grow there, and only grass and weeds be- 

 fore cultivation — corn does not grow well— small grain better— and cotton 

 soon becomes subject to the rust." The excessive proportion of calcareous 

 earth is evidently the cause of its barrenness. 



The substratum called lime-stone is soft enough to be cut easily and 



