The mineralogical composition of the clay fraction and the non -carbonate residue in the parent rocks of 9 Mediterranean brown forest soils was determined, using X-ray diffraction DTA, Integral Thermal Analysis, electron microscopy and precise chemical analytical technique.
kaolin. h I f ' f h 'I d i th The percentage ratio (montmorin + illite) in t e c ay raction 0 t e SOl an in e noncarbonate residue of the corresponding parent material was analyzed statistically and found low correlation. This is to be expected because of the great variability in the parent rock and the difflculty of collecting representative samples of the rocks. The genesis of these soils was compared to that of terra-rossa and rendzina soils (for which there is a very high correlation between rock and clay). The dominant clay mineral present was montmorillonite. In some soils fairly high amounts of kaolin were found. The basis for considering this soil type as a bridge between terra-rossa and rendzina is discussed.