MARL AND MARLING IN ENGLAND. 109 



convenient distance and relied upon the subsequent effects to 

 direct whether the operation should be continued or abandoned. 

 These remarks more especially apply to the older writers ; but 

 even the later authors, of the highest character (as Sinclair and 

 Young, for example), when telling of the practical use and valua- 

 ble effects of marl, omit giving the strength of the manure, and 

 generally even its nature and in no instance have I found the in- 

 gredients of the soil stated, so that the reader might learn what 

 kind of operation really was described, or be enabled to form a 

 judgment of its propriety. From all this, it follows that though 

 what is called marling in England may sometimes be (though 

 very rarely, as I infer) the same chemical operation on the soil 

 that I am recommending, yet it may also be either applying clay 

 to sand, or clay to chalk, or true marl to either of those soils, or 

 to some other soil still more calcareous than the earth applied ; 

 and the reader will generally be left to guess, in every separate 

 case, which of all these operations is meant by the term marling. 

 For these reasons, the practical knowledge to be gathered from all 

 this mass of written instruction on marling will be far less abund- 

 ant than the errors and mistakes of the authors, and the consequent 

 inevitable false deductions by their readers. The recommenda- 

 tions of marl by English authors, induced me very early to look 

 to what was here called by the same name, as a means for improve- 

 ment. But their descriptions of the manure convinced me that 

 our marl was nothing like theirs, and thus actually deterred me 

 from using it, until other and original and more correct views in- 

 structed me that its value did not depend on its having " a soapy 

 feel," or on any admixture of clay whatever.* 



[* The remarks above were written in 1820, and are much less applica- 

 ble to authors of later date. How well justified my expressions then were, 

 will fully appear in the Appendix, in the testimony furnished by quotations 

 of the language and opinions of many authors. 



There is no want of precision and clearness in the definitions of marl 

 given by modern scientific writers. Though even with some of them, there 

 are still very remarkable misapplications of the terms ; as incorrect, in- 

 deed, as could be expected from the most ignorant cultivators. Tims the 

 former geological surveyor of New Jersey habitually applies the name of 

 marl to the " green-sand" of that country; which remarkable earth is a 

 soft incoherent crumbly mass of separate grains, neither clayey nor marly 

 in texture or compactness, nor in the least calcareous in its chemical com- 

 position. Still more strange than this, is an example found as late as 

 1849, in the " Second Visit to the United States" of the distinguished 

 geologist Sir Charles Lyell. This author says, when passing from New 

 York to Philadelphia, " In New Jersey we passed over a gently undulating 

 surface of country, formed of red marl and sand-stone, resembling in appear- 

 ance, and of about the same geological age as the new red sand-stone 

 (trias) of England." Vol. i. p. 191. This error was not caused by 

 merely the careless use of an incorrect provincial term ; for the "new red 



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