Deposits of the underlying stratum are darker and are characterized by platy parting; along the planes of which there are signs of
ferrugination (thin films of iron hydroxides).
The chorionic villi were large and cellular, with convoluted outlines and presence of both trophoblastic pseudoinclusions (Figure 2(c)), secondary to villous scalloping, and focal robust ferrugination of the basal lamina (Figure 2(c)), highlighted by iron stain (Figure 2(d)).
We regard the above-mentioned "basophilic stippling" of villous basement lamina a nonspecific finding which is usually positive for iron; hence we call it ferrugination [19].
Ferrugination caused by Monsel's solution: clinical observations and experimentations.
Our results suggest that the following are the dominant pedogenetic processes that produced both soils: loss of bases and acidification, clay formation,
ferrugination, weathering of clay, and structure formation.
Ferrugination is an edaphogenic process in these regions, characterised by the release of oxides of iron and silicates which only allows the formation of clays, like kaolinite, which are poor in silicates and are typical of ultisols.