Collisionally processed rocks on Mars

The Pathfinder Landing site on Mars has boulders that may be cratered (Stim py), split (Chimp), fragmented (Book End and Flat Top), or otherwise partly destroyed (Yogi and Frog) by collisional processes. Atmospheric-entry calc ulations show that centimeter-sized projectiles survive passage through the martian atmosphere and encounter the surface of Mars at velocities of a fe w kilometers per second. Craters Less than 1 meter in diameter may contribu te to the evolution of the martian surface and its soils.