Underside P-reflections at mantle discontinuities are difficult to observe directly on seismograms mainly because of their low amplitude. It is shown that stacking seismograms obtained at several epicentral distances but having their PP bounce points in the same region, enables the indentification of such phases. This method is applied to data from Japanese and Taīwan events recorded by the NARS array and other broadband European stations; discontinuities at about 670 and 300 km are revealed beneath Northern Eurasia. ¿ American Geophysical Union 1988