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INTRODUCTIONOne of the problematic features of the Himalayan geology relates to the inverted metamorphism exhibited by the central crystalline rocks as well as by the rock sequences of the Lesser Himalayan nappe. The inverted metamorphism in the Himalayas means an increase in the Barrovian metamorphism of the rocks from the chlorite grade at the lowest structural level to the silliraanite grade associated with anatectic granites at the highest. The explanations offered for this feature are varied. These include postmetamorphic recumbent folding on regional scale, interzonal thrusting, and high-level granite intrusion under regional stress. None of these explanations is free from geological constraints [Sinha-Roy, 1974, 1977b.In recent years, the Main Central Thrust (MCT) has been central to the concept of continental underthrusting, and the data primarily from its upper plate have been considered for explanations for the inverted metamorphism. The temperature regime is contended to be partly controlled by thrust-related frictional heating and radioactive heating through doubling of the continental crust [Bird et al., 1975]. Bird [1978] rejected these possibilities, however, and suggested a process of lithospheric delamination and mantle upwelling to explain the thermal history and the subsequent generation of the MCT. This explanation seems to suffer from certain geological drawbacks. As thrusting is most probably linked with the development of metamorphic sequences in the Himalayas, the purpose of the note is to deal with some geological aspects of inverted metamorphism as related to thrust development, particularly the MCT.