Redoximorphic features are considered pedogenic features. However we recognize that these features can form relatively rapidly and occur in deep or otherwise unaltered layers that we would prefer to consider as ""not part of the solum"" (C horizons). Therefore we require additional
Pedogenesis, even if the reduction is strong, for a layer to be considered as a B horizon and as a cambic horizon. Cg horizons are common especially in wet alluvial soils. If the redox features are strong as defined in item 2.a.(3) on page 37 of Soil Taxonomy and the other required items are met the layer is a cambic horizon and should be designated as a Bg horizon.
A layer at the top of dense till with many redox concentrations in it should be considered B horizons if it also has soil structure. If the structure is weak or very coarse the horizon will likely meet the requirements of the fragipan and I would use Bx as the horizon designator.
We (Bob Ahrens, some others) and myself consider the large polygonal structure in glacial till as pedogenic structure. We think it may have formed as a permafrost feature. I would like to see some oriented clay in the thin sections from a fragipan, but this cannot be a requirement, since some fragipans are formed in albic materials (Ex horizons).
