MARL. 81 



second less so. The defect in each is thus remedied. 

 Marl has somewhat the appearance of fine clay, 

 but of a color considerably lighter, and like clays, 

 seems to be of a greasy consistence ; yet it is not te- 

 nacious like clay, but crumbles to pieces between the 

 fingers. It has very little or no smell , and tastes very 

 like chalk. It is found in many parts of our widely 

 extended country ; sometimes in wet flat lands, and 

 at other times under sand banks, by the margin of 

 rivers. 



It is difficult to keep vegetable matter in a sandy 

 soil, as it gives it up readily, not only to plants, but 

 is vaporized and carried off by the heat of the sun's 

 rays. Hence it is called a hungry soil, and hence, 

 too, I recommend it to be covered by clover or grass 

 to protect it from the volatilizing power of the sun. 

 All sandy soils need clay and a portion of calcareous 

 matter to improve their texture and increase their fer- 

 tility. Marl at once answers this purpose, as it con- 

 tains both clay and lime, The quantity put on the 

 soil should be in proportion to the deficiency of these 

 substances in the soil. It is said that the effect of marl 

 on the sandy soil will be seen for twenty or thirty 

 years. This arises irom, and proves the fact, that the 

 earths do not constitute the food of plants, but that 

 the soil is only the stomach which digests, or assimi- 

 lates the animal and vegetable matter which nourishes 

 and enters into the composition of plants. The very 

 best soil is that in which the three earths, sand, clay, 



