Marl

Only a few marl ponds are known in New York State, and their borders are always occupied by unusual plants. Marl, composed chiefly of shells, was formerly used as a fertilizer, but it sometimes contains harmful substances. The Shrubby cinquefoil, or hardhack, has its center if variation in southwestern China. In western Europe it is found only in half a dozen localities, because its range has been disrupted by glaciation. The little marl sedge (Carex Viridula) occurs along the seacoast and inland in calcareous regions from Newfoundland to southwestern Alaska.

The soil profile is composed mainly of shells.