| |
| | marl |
 | | Marl is usually gray; it is used esp. as a fertilizer for acid soils deficient in lime. |
 | | In the Coastal Plain area of Southeastern United States, the term has been used for calcareous clays, silts, and sands, esp. those containing glauconite (greensand marls); and for newly formed deposits of shells mixed with clay. |
 | | A soft, grayish to white, earthy or powdery, usually impure, calcium carbonate precipitated on the bottoms of present-day freshwater lakes and ponds, largely through the chemical action of aquatic plants, or forming deposits that underlie marshes, swamps, and bogs that occupy the sites of former (glacial) lakes. |
| www.webref.org /geology/m/marl.htm (265 words) |
|