154 Review of Essays on Calcareous Manures. 



ter used with great success. * Yet clover, when aided by putrescent 

 manures, is a successful crop, on the gneiss, without the artificial aid 

 of plaister; but this is readily accounted for, as sulphuret of iron is 

 not rare, which being decomposed, and thus yielding sulphuric acid 

 to combine with the lime of the feldspar, supplies the necessary food 

 of the plant. In England, too, where a saline air, prevailing almost 

 universally, is generally supposed to forbid the use of gypsum, there 

 are calcareous soils on which it is beneficial, as in Kent, which is as 

 much exposed to the blast of the sea as almost any part of the king- 

 dom. Among the many advantages of calcareous manures, then, 

 may be mentioned, as not the least, that it will prepare the way for 

 the introduction of the clover husbandry, in regions where it would 

 otherwise be impracticable. 



Mr. Ruffin's own experience is limited to the regions of Virginia 

 within reach of the tide, and to these his remarks are, with a just 

 philosophical spirit, restricted, yet his extensive experience and ac- 

 curate observation furnish the ground for a theory which must be 

 useful, if properly understood and applied, in any district whatsoever. 



The soils of this region were, on examination, found to be wholly 

 destitute of calcareous earth, except a few isolated spots inclosed with- 

 in them, which were observed to manifest, even to the eye, fragments 

 of shells, and yielded lime on analysis. These spots were proverbial 

 for their fertility, and remarkable for the fact, that on some of them 

 long continued successions of the same crop had been annually cul- 

 tivated, without absolute exhaustion. On a careful examination, Mr. 

 Ruffin found that these shells, supposed to be the relics of Indian 

 encampments, were the outcrop of fossil layers, and he succeeded 

 in tracing these layers to his own land. 



"My use of calcareous earth, as a manure, has been almost en- 

 tirely confined to that form of it which is so abundant in the neigh- 

 borhood of our tide waters, the beds of fossil shells, together with 

 the earth with which they are found mixed. The shells are in va- 

 in some beds generally whole, and in others reduced 

 nearly to a coarse powder. The earth which fills their vacancies, 

 and makes the whole a compact mass in most cases, is principally 

 siliceous sand, and contains no putrescent or valuable matter, other 

 than the calcareous. The same effects mi^ht be exoected from cal- 



/ 



nous states 



* It has been used, with entire success, on lands washed by the sea, at Stamford, 

 in Connecticut, by the late Mr. Moses Rogers.— Ed, 



