274 



Marl. 



Vol. VI. 



For the Farmers' Cabinet. 

 9IarI. 



This is one of those terms which, having 

 been applied to many dissimilar substances, 

 has aimojt ceased to have any definite and 

 distinctive meaning, further than as it may 

 be used as a generic term to denote any sub- 

 stance dug out of the earth and applied, with- 

 out further preparation, as a manure to land. 



It is said that " in England the most scien- 

 tific agriculturists apply the term marl cor- 

 rectly to a calcareous clay of a peculiar tex- 

 ture, but most authors', as well as mere culti- 

 vators, have used it for any smooth, soapy 

 clay which may or may not have contained, 

 8o far as they knew, any proportion of calca- 

 reous matter." It has been divided into 

 shell-marl, composed of fragments of shells, 

 and earth-marl ; the latter is again subdivided 

 into five sorts : " 1, Coroshut marl, which is 

 brown, mixed with fragments of chalk and 

 blue veins. 2. Stone, slate or flag marl. It 

 resembles blue slate, and crumbles easily 

 •when exposed to the weather. 3. Pont marl 

 or delving marl; it is brown, and rough to 

 the touch. 4. Clay marl, which contains 

 much clay as its name denotes. 5. Steel 

 marl; its colour is black, its consistence like 

 that of bits of paper." Other writers tell us 

 that the " virtue of all these different kinds 

 of marl is the same, and tliat they may be all 

 used on the same ground without the small- 

 est difference in their effect ; and that marl 

 without any reference to its colour may be 

 known by its pure and micompounded na- 

 ture. There are many marks to distinguish 

 it by; such as its breaking into little square 

 bits; its falling easily to pieces by the force 

 of a blow, or upon being exposed to the sun 

 and the frost ; its feelmg fat and oily, and 

 shining when it is dry. But the most uner- 

 ring way to judge of marl, and know it from 

 any other substance, is to break a piece as 

 big as a nutmeg, and when it is quite dry, 

 drop it into a glass of clear water, where, if 

 it be right, it will dissolve and crumble, as it 

 were, to dust in a little time, shooting up 

 sparkles to the surface of the water." 



Can any thing be more vague and unsatis- 

 factory tlian such definitions and descriptions. 

 Yet such is the account of it we find in books. 

 We do not pretend to understand it, and shall 

 therefore not undertake to explain it to others, 

 nor to decide to which of the different sub- 

 stances the term marl most properly applies. 



We have several dissimilar substances in 

 this country known under the general term 

 of marl. To a kvf of these we shall now ad- 

 vert. And first of calcareous marl. This 

 article, under the name of pond marl, is thus 

 noticed by Prof H. D, Rogers in his report 

 on the Geology of New Jersey. " At seve- i 



ral places in the limestone districts of the 

 Kitlatting Valley we meet with a material 

 which is identical with the lake niarl of Eu- 

 rope, occurring around the shores and in the 

 beds of small lakes, and throughout some of 

 the swampy meadows of Sussex and Warren 

 counties. This useful deposite is only found 

 where the water is copiously impregnated 

 with the carbonate of lime, and hence it oc- 

 curs only within or immediately adjacent to 

 extensive limestone strata. The ponds where 

 this deposite occurs present a rather singular 

 aspect, being fringed with a broad white 

 beach, and from this circumstance are fre- 

 quently called White Ponds. 



Analysis of a fresh-water marl from a pond 

 four miles from Newton : 



Description. — Light ash colour ; pulverulent. 



Composition in KM) parts: 



Carbonate of lime, 90.22 



Carbonate of maiL'Uf'sia, 1.91 



Ahiiniiia and peroxide of iron, O.til 



Insoluble matter 3.13 



Organic matter, moisture and loss, 4.13 



100.00 



This kind of marl must evidently owe its 

 fertilizing power to carbonate of lime in a 

 very finely divided state. "A material so 

 easy of access, demanding no preparation to 

 suit it for the soil, and unquestionably so effi- 

 cient when judiciously applied, ought to be 

 extensively used" wherever it can be obtain- 

 ed. " Though much neglected until recently, 

 this useful substance is beginning to attract 

 attention to its valuable properties as a ma- 

 nure. Ample evidence is furnished of its fer- 

 tilizing agency by experience in Sussex 

 county, even if we had not the testimony of 

 many districts of Europe in its favour." 



The next variety we shall notice is the 

 greensand or Jersey marl; and shall again 

 make use of Prof. Rogers's report on the Ge- 

 ology of that state — occasionally condensing 

 his statements, the better to suit our present 

 purpose. This material is known to exist 

 extensively in the lower parts of New Jersey 

 and Delaware, and will probably be found in 

 other states further south. 



" The prominent and often the sole ingre- 

 dient of these marl or greensand beds is a 

 peculiar mineral," to which the name of 

 greensand has been applied, " occurring al- 

 ways in the form of small, dark granules 

 about the size of the grains of gunpowder: 

 their form is roundish and they are often conv 

 posed of two or three smaller ones united to- 

 gether, a distinctive feature by which they 

 may at once be recognized from other dark 

 kinds of sand. The prevailing colour of the 

 grains is a deep green, though sometimes tha 

 colour is as light as that of the green paint 

 called verditer." " Tiiough the green gran- 

 ular mineral above described constitutes the 



