The result of residual magnetization investigation in the gabbroids of Volyn and the ferruginous quartzites of the Kremenchug anomaly as well as some other metamorphic rocks of the Ukrainian crystalline shield are considered. All the intensely magnetic rocks show a common dependence of the residual magnetization on magnetic susceptibility. A regular deviation of the residual magnetization direction from that of the present magnetic field of the earth is observed. The mechanism of the thermomagnetization process is as follows: the magnetized body at every given moment is a certain cooling layer (the Curie layer) with the Curie temperature. In consequence of the lit-par-lit (gradual) cooling of the rocks their thermomagnetization in nature is necessarily dependent on the law of thin-layer magnetization. A mathematical analysis is given of the regularities observed-in the direction of the residual magnetization vector in accordance with the cooling surface position (the Curie layer) with regard to the field ...