TESTIMONY IN OPPOSITION. 491 



tity;" Gloucester Town, " richly specked with green-sand;" Saun- 

 ders', Isle of Wight (one only of three strata), " considerable 

 green-sand." Stith's, Surry, "quite richly specked with green- 

 sand." A. C. Jones's, Surry, and at Kingsmill, James City, " in- 

 termixed with green-sand." Now what proportions these descrip- 

 tions designate, it is not for me to determine ; but 3 or 4 per cent., 

 at most, would abundantly serve to meet all their requisitions. 

 There are also 7 other of the specimens named marked in less de- 

 grees by the presence of this ingredient, and which are described in 

 this respect in such phrases as these : containing " a little green- 

 sand" "specked with green-sand" "quite perceptibly specked 

 with green-sand" " tinged with green-sand" and " slightly inter- 

 mixed with green-sand." There remain of the list 135 other speci- 

 mens, of which 48 are stated to contain of " green-sand a trace" 

 (by which term chemists understand a proportion so small that its 

 presence is barely certain), and of the other 87 specimens no green- 

 sand is mentioned, and therefore it may be inferred that not even 

 " a trace" could be found. 



If this list of marls and statements of their fertilizing contents 

 had been presented by the author distinctly as a designed refutation 

 of his previously and repeatedly published assertions of the frequent 

 abunoance and general presence in useful quantity of green-sand in 

 miocene marls, nothing could have been more to the purpose, or 

 more conclusive. 



Nevertheless, few and rare as may be the cases in which the value 

 and beneficial effects of miocene marls are increased in any consi- 

 derable degree by the presence of green-sand, or of any other in- 

 gredient than carbonate of lime, it is important that such auxiliary 

 fertilizing matters should be searched for, and their absence or pre- 

 sence known. The great value and uniform fertilizing effects of 

 carbonate of lime will be the most highly appreciated by those 

 farmers who understand and estimate them separately and alone ; 

 without confounding the operation of that manuring earth with 

 those of any other intermixed and unknown substances, no matter 

 what increase of benefit such intermixture may produce in particu- 

 lar cases. 



Some years after the publication of the first edition of this Re- 

 port (as originally made to the State Board of Agriculture of Vir- 

 ginia, and published, with other reports, by order of the legisla- 

 ture), I learned that a particular bed of marl, worked at Hampstead 

 in New Kent, and more lately found and now worked both at Oak 

 Spring and Liberty Hall, in King William county, furnished an 

 exception to the general rule above asserted, of the absence of any 

 large proportion of green-sand in miocene marl. This particular 



