I860.] 



THE SOUTHERN PLANTER. 



673 



considering its fertilizing value. The ad- 

 mixtures of clay, quartz sand, etc., are quite 

 variable, ranging in quantity from 10 to 60 

 per cent, of the whole; thus more or less 

 reducing the amount of manurial matters, 

 and at the same time either improving or 

 injuring the general composition by their 

 own accidental ingredients. 



The clay mixed with or overlying the 

 green sand, in many localities contains quan- 

 tities of a shining yellow mineral called iron 

 pyrites or " fool's gold," which consists of 

 iron and sulphur, and by exposure to the at- 

 mosphere is converted? into sulphate of iron, 

 (common copperas or green vitriol.) From 

 this source the marl is sometimes so impreg- 

 nated with sulphate of iron as to be destruc- 

 tive to vegetation when applied fresh from 

 the pits. This difficulty is not, however, 

 general, so far as T can learn, and in all cases 

 is obviated by exposing the marl for a year 

 or so to the weather, and by composting it 

 with lime or with stable manure. By these 

 means the iron is changed from the protoxyd 

 to the peroxyd, which latter is harmless 

 under all circumstances. 



In some localities the marl is mixed with 

 a large proportion of fragments of shells, 

 and thus contains considerable carbonate 

 and a small amount of phosphate of lime. 

 Sulphate of lime or plaster, is also an occa- 

 sional ingredient. 



The following analyses copied from Pro- 

 fessor Cook's Report on the (Geology of New 

 Jersey, clearly show the nature and extent 

 of the variations in composition, to which 

 the marl as employed for agricultural pur- 

 poses is subject. 



Analyses* 



1 ' 2 3 4 5 6 



Protoxyd of iron, 8.3 16.8 12.3 14.9 



Alumina, - - 6.1 6.6 8.0 



Lime, - - 2.4 12.5 1.0 



Magnesia, - - .4 '2.6 2.0 



Potash, - - 2.5 4.f> 7.1 7.1 4.3 3.7 



Soluble silica, . - 20.2 31.2 45.9 

 Insoluble silica 



and sand, - - 49.9 5.6 4.0 



Sulphuric acid, - .9 .6 .4 



Phosphoric acid, - 1.4 1.1 1-3 .2 2.6 6:9 



Carbonic acid, - .2 9.3 



Water, - - 7.1 8.9 8.1 



Soluble m water, - 1.9 1.4 1.11.1 1.9 4.7 



Potash it is seen ranges from 2i to 7 per 

 cent. The average is about 4$ per cent. 



*Tn copying the analyses, the decimals of 

 the percentages have been abridged from two 

 figures to one. 



43 



One of the specimens is half sand and inso- 

 luble matters. No. 2 contains 12 £ per cent, 

 of lime, and 9 per cent, of carbonic acid, 

 or 21 per cent, of carbonate of lime. Phos- 

 phoric acid is almost wanting in No. 4; but 

 in No. 6 exists to the amount of 7 per cent. 

 The usual quantity of phosphoric acid how- 

 ever, does not exceed 1 to 2 per cent. 



From the composition of the green sand 

 marl we might know that it is a good manure 

 without any actual trials ; but the experience 

 of the New Jersey farmers during many years 

 has so fully demonstrated its value, that the 

 question arises — may it not be procured and 

 transported so cheaply as to admit of profit- 

 able use in this State ? The following quo- 

 tation from Professor Cook's Report may 

 serve to assist us in answering this question. 



" The absolute worth of the marl to far- 

 mers it is difficult to estimate. The region 

 of country in which it is found has been 

 almost made by it. Before its use the soil 

 was exhausted, and much of the land had 

 so lessened in value that its price was but 

 little, if any more than that of government 

 lands at the West; while now, by the use 

 of the marl, these worn out soils have been 

 brought to more than native fertility, and 

 the value of the land increased from fifty to 

 a hundred fold. In these districts, as a 

 general fact, the marl has been obtained at 

 little more than the cost of digging and 

 hauling but a short distance. There are in- 

 stances, however, in which large districts of 

 worn-out land have been entirely renovated 

 by the use of these substances, though situ- 

 ated from five to fifteen miles from the marl 

 beds, and when, if a fair allowance is made 

 for labor, the cost per bushel could not have 

 been less than from twelve to sixteen cents. 

 Instances are known when it has been 

 thought remunerative at twenty-five cents 

 per bushel." 



The New Jersey Fertilizer Company de- 

 liver the marl on board vessels at their 

 wliarf at Portland Heights, N. J., for seven 

 cents per bushel. The bushel when first 

 raised weighs 100 lbs.; when dry, 80 lbs. 

 I doubt not that the average qualities of 

 this marl are much better, bushel for bushel, 

 than leached ashes. The best kinds are 

 much superior, and in the inferior sorts 

 there is much more weight of valuable fer- 

 tilizing matters than in an equal bulk of 

 leached ashes; but this advantage has its 

 offset in the superior fineness, and conse- 

 quent greater activity of the leached ashes. 



