MARL AND MARLING IN EUROPE. 371 



known anywhere there twenty years ago, it is now known to be 

 abundant, and generally to be found, though almost always a few 

 feet below the sur/ace of the low lands. 



Many persons who would concur with me as to the premises and 

 results, would yet ascribe the colouring of certain waters to the 

 more level surface of the land, and the more sluggish and stagnant 

 state of the waters ', and would suppose the absence of colouring 

 matter in the waters of- the upper country to be caused by the 

 rapidity of the descent and of the passage of the streams. This 

 would be a correct view, if the matter in question were the degree 

 of intensity of colour, instead of the existence or entire absence of 

 colour. It is true, and obvious, that if the coloured waters which 

 now creep and stagnate over the level lands below the falls, had as 

 rapid a descent and free discharge as the mountain torrents, their 

 colour could not become darker, with time, by long infusion of the 

 leaves, nor by evaporation of still waters. But though the colour 

 would be much more pale, its existence would not be the less cer- 

 tain. The source of colouring matter, the soaking of dead leaves, 

 &c., in rain-water, is as abundant in the upper as in the lower 

 country ; and the more rapid discharge of the waters, if no other 

 cause of clearing them operated, would not prevent their becoming 

 and remaining coloured, as generally, and, however more pale in 

 tint, would be seen as obviously, as in the most level lands. But 

 this is not all. Though there is almost no level land, and therefore 

 no swamps in the hilly or still less in the mountain region, there 

 are mill-ponds in the lower hilly country, and natural lakes in the 

 mountain region. If there was the slightest tint of dissolved colour- 

 ing matter in the streams, the waters when collected in these deep 

 reservoirs could not foil to exhibit the colour much more deeply. 

 Yet no one such fact is known, or is believed to have existence. 



NOTE II. EXTENSION OP THE SUBJECT OP PAGES 108 113. 



The statements of British authors on marl, and their applications 

 of the name, generally incorrect, and often contradictory. Both 

 the terms "marl" and " marling" have different significations 

 in Britain and in Virginia. 



CUSTOM has compelled me to apply improperly the name marl 

 to our deposits of fossil shells. But as I have defined the ma- 

 nuring by means of this substance, which is called marling (and 

 for which I suggested calxing as a much better and also more com- 

 prehensive name), to be simply rendering a soil calcareous any 

 term used for that operation would serve, if its meaning was always 

 kept in view. But, unfortunately, this term (marling) is of old 



