Frictional motion on ground sliding surfaces of Westerly granite, Twin Sisters dunite, and Spruce Pine dunite and on the various combinations of these rocks was studied. Stable and episodic sliding and stick slip motion were observed for all combinations of Westerly granite and Twin Sisters dunite. Stick slip was observed when Spruce Pine dunite slid on granite or on Twin Sisters dunite, but only stable sliding and episodic sliding were observed when Spruce Pine dunit slid on itself. There are systematic differences in the frictional behavior of the different lithologies and also in the effects of different types of gouge. Pre-stick slip creep was observed before all events and thus may be characteristic of stick slip.