Definition of "marl" [marl]

• A crumbly mixture of clays, calcium and magnesium carbonates, and remnants of shells that is sometimes found under desert sands and used as fertilizer for lime-deficient soils. (noun)
• To fertilize with such a mixture. (verb-transitive)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "But what (hall I fay if our whitifh foft clay grounds (whence is fometimes digged, what we call marl for manure of our lands) do grow f Ilhall relate a ftory that may fcem to give coun - tenance hereunto."
• "Closely associated with limestone in commercial uses, as well as in chemical composition, is calcareous marl, which is used extensively in the manufacture of Portland cement."
• "Many of the hills of Warren County, in which Vicksburg is situated, are composed of a curious soft limy clay, called marl, which, normally, has not the solidity of soft chalk."