Limnic Mesisol (LM.M)
Common horizon sequence: Of, Om or Oh, Om, Oco, Om
Soils of this subgroup have the general properties specified for the Organic order and the Mesisol great group. They differ from Typic Mesisols by having a limnic layer beneath the surface tier. A limnic layer is a layer or layers at least 5 cm thick of coprogenous earth (sedimentary peat), diatomaceous earth, or marl. Also they may have fibric, humic, and cumulic layers but do not have terric or hydric layers.
Note: Diagnostic horizons are underlined.