86 



FARMERS' REGISTER 



rNo.2 



it should be ploughed up and repeatedly harrow- 

 ed, so as to ensure its intermixture. 



7thly. Clays and stront^ loams require a full 

 dose; but tor sands and other liirht soils, chalk, or 

 a much less quantity oC Imie, will serve — each in 

 proportion to the strength of the lime and of the 

 lanil. 



8thly. If the land be not supplied with the 

 same quantity of putrescent manure that is usual- 

 ly laid upon other soils, the crops will suffer; and 

 if it be not then laid down to grass for a long 

 series of years, it will be worn out and exhaust- 

 ed. 



[To be continued.] 



DESCRIPTION, AND STATEMENT OP THE IN- 

 GREOIENTS, OF THE EARTH IMPROPERLY 

 CALLED "marl" IN NEW JERSEY. 



Extract from Medical arid Physical Researches, by Dr. Richard 



H.illLAN. 



[It is feared that many of our readers think that we 

 have been disposed to supply them, in unnecessary pro- 

 fusion, with information on Wlurl, and its use as ma- 

 nure. Yet, however copious may have been the sup- 

 plies of information furnished directlj'^ from our own 

 observations, or gathered from those of others — and 

 liowever successful may have been, in some respects, 

 these eflbrts to instruct, there are still other branches of 

 this extensive subject, on which almost nothing is yet 

 perfectly understood — and in regard to which most 

 of the many publications that have been made, have 

 served to increase, rather than to dispel the obscurity 

 which envelopes the subject. We allude to the earth 

 improperly called "Marl" in New Jersey — called 

 "green sand" by geologists, and to which (long before 

 we had ever heard of the latter term,) we affixed the 

 (equally improper) name of "gypseous earth," in 

 1817, when we discovered its existence in great quan- 

 tity in the banks of James River, Virginia, and con- 

 tended for its identity with the earth called "marl" 

 in New Jersey.* It was not until the appearance of 

 the first communication on green sand in Virginia, 

 from Professor W. B. Rogers, (p. 129, of vol. II. Far. 

 Reg.) that any share of public attention was attracted 

 to this subject, south of New Jersey. . Since then, 

 much interest has been felt and expressed, in Virginia 

 and JMaryland, and much informatiom, scientific and 

 practical, has been furnished by Professor Rogers and 

 others: but still we repeat that almost nothing is yet 

 known as to the cause of the mysterious operation of 

 this substance — and that much misunderstanding and 

 delusion have been caused by improperly compre- 

 hending (in common parlance) this and other very dif- 

 ferent substances, under the one general name of 

 "marl.'''' In the Essay on Cnlcareous Manures, much 

 was said upon the then existing and very great con- 

 fusion and obscurity caused by this term being applied 

 to manures of different chemical composition, and 

 of different modes of operation. But since that work 

 was published, the confusion of ideas, and of sub- 



* See nrticle on the Gypseous Earth of James Kiver, No. 4. 

 Vol I, Far. Ucg. and p. 105 of JEssay on Cal. Manures, 2d. Ed. 



stances of different kinds, has been made still worse, 

 by the "green sand" or Jersey earth," becoming known, 

 as existing extensively on Virginia and Maryland, and 

 by its being also called marl, whether destitute of car- 

 bonate of lime, or mixed with shells or calcareous 

 matter. The Essay on Calcareous Manures treats of 

 that "marl" of which the sole, or at least the princi- 

 pal ingredient, acting as manure, is calcareous earth, or 

 carbonate of lime. It mentions other ingredients, and 

 amor)g them "green sand" as sometimes found in marl, 

 and adding to their value — but considers these as ac- 

 cidental exceptionsto the general rule — and professes 

 neither to explain nor to discuss the mode of operation 

 of these accidental ingredients.* Still we frequently 

 find that our correspondents, and other readers of the 

 Essay, confound the marl there treated of, with the 

 "green sand," even when the latter contains not apar- 

 Hcle of carbonate of lime — and more often, they draw 

 no distinction between the former in a pure state, and 

 the calcareous marl having a large admixture of the 

 green sand," and thereby greatly improved in its va- 

 lue, and altered in its action as manure — though, as 

 we think, the cause of that action has not yet been ac- 

 counted for. Professor Rogers, in his several interest- 

 ing communications to the Farmers' Register, on this 

 subject, seems to attribute the wonderful effect of this 

 manure principally, if not entirely, to the potash which 

 it contains. This inference (from the analysis there 

 stated) is plausible, (as there is no other knoivn fertil- 

 izing ingredient,) and would be conclusive, if potash 

 was always present, and in sufficient quantity. But 

 -we more than distrust this explanation— because, ac- 

 cording to our personal experience, the green sand, 

 though sometimes producing wonderful effects, has 

 generally been but of transient and light value — ana 

 never worth using, except on soils made calcareous at 

 the same time,- or previously. Our distrust is strength- 

 ened by the following extracts from the lately publish- 

 ed work of Dr. Harlan. , By the analyses here stated, 

 neither of the specimens of the two great classes of the 

 "Jersey Marl" contain any proportion of potash. 

 They also furnish new evidences (in addition to the 

 many exhibited before in this journal) that the value, 

 as manure, is not attributable, in any degree, to lime — 

 for there is but little more than 1 per cent, of lime in 

 the specimen of what is called "fertilizing marl," and 

 not a trace of it in the "non-fertilizing." 



We are very far from meaning to speak slightingly 

 of the "green sand marl" as manure. Its effects in 

 numerous particular cases (though far from universal- 

 ly,) have certainly been not only highly valuable, but 

 wonderful — and the investigation of the mysterious ac- 

 tion of this manure strongly invites the continued re- 

 searches of scientific men — and from the result of such 

 researches, we may hope for most valuable instruction 

 to farmers, and much improvement and profit to agri- 

 culture. But we maintain, that no satisfactory expla- 

 nation of these effects has yet been given — and we 

 warn our readers against confounding the effects and 

 mode of operation of calcareous marl, as manure, with 

 those of the green sand, whether alone, or combined 

 by nature, or by art, with calcareous manures.] 



*B3say on Cal. Manures, 2d. Ed. pp. 48, 49, 68 and 92. 



