histosol

Unlike other soil orders, Histosols are not considered primarily mineral, but organic. They are commonly called bog, moor, peat, or muck; they are last in the list of soil orders, last in areal importance, and have been given the least amount of attention in the more recent soil classification systems. […] Histosols are more than 12 to 18 percent organic carbon by weight (depending on the clay content of the mineral fraction and the kind of materials) and well over half organic matter by volume. Unless drained, most Histosols are saturated or nearly saturated with water a large portion of the year.