MARL

n. soil which consists mostly of calcium-rich clay and has fertilizing properties

For the towns in Germany see Marl (disambiguation). Marls are calcium carbonate or lime-rich muds or mudstones which contain variable amounts of clays and calcite or aragonite. The term is most often used to describe lacustrine (lake) sediments but may also be used for marine deposits. The term 'marl' is widely used in English-language geology, while the term seekreide is used in European references.
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Noun
1. a loose and crumbling earthy deposit consisting mainly of calcite or dolomite; used as a fertilizer for soils deficient in lime
(hypernym) soil, dirt

v. marl

(v. t.)
To cover, as part of a rope, with marline, marking a pecular hitch at each turn to prevent unwinding.
  

(n.)
To overspread or manure with marl; as, to marl a field.
  

(n.)
A mixed earthy substance, consisting of carbonate of lime, clay, and sand, in very varivble proportions, and accordingly designated as calcareous, clayey, or sandy. See Greensand.