High-resolution photographs of the lunar surface obtained by the U.S. Lunar Orbiter Satellites in 1966-1967 have revealed the concentration, in many regions, of boulders between 1-20 m. in size, with a fairly sharp frequency cutoff above this limit (due probably to finite rock strength). Such boulder fields are found, in particular, to abound on the tops of small domes (well evidenced, for instance, on the floor of the crater Copernicus), but occur also in flatlands. This new evidence--combined with out present knowledge of the bearing strength of the lunar surface disclosed by the soft-landers--shows that such boulders could not have been deposited in their present exposed positions by any kind of impacts (including the secondary or tertiary ones); for any boulders impacting with a velocity of the order of 100 m/sec or greater would have penetrated under the surface to a depth equal to many times the actual dimensions of the impacta. It appears, therefore, almost inevitable that the boulders we see now (particularly in lunar flatlands) must have been gradually exhumed from their original underground locations by mechanical erosion processes (principally moonquakes triggered by primary impacts). (Author).