1. Rare earth elements in ultramafic rocks from mafic-ultramafic massifs of folded regions -- 2. Rare earth elements in ultramafites from deep xenoliths in alkali basalts -- 3. Rare earth elements in hypabyssal and subvolcanic rocks with high in magnesium composition -- 4. Rare earth elements in plutonic mafic rocks -- 5. Rare earth elements in rock-forming minerals from ultramafic and mafic rocks -- 6. Indicator properties of rare earth elements and their role in studies of genesis of rocks and minerals from mafic-ultramafic complexes.