“…of the Institute of Physics of the Earth, AN SSSR, 1966). In particular, laboratory studies on velocities of elastic waves in rock samples from specific regions enable one to define the types of rocks which form the specific layers of the crust, the presence of which was established by deep seismic probing (Afanas'yev, 1965;Volarovich, 1964;Volarovich et al, 1965). The present paper deals with such a study of one of the regions of the Baltic shield.…”