Tool typology. See my answer way back in post 19.
C14 is not very useful past about 50,000 years and completely useless on inorganic material (like stone), because it has no carbon.
Not because it has no carbon because it may have some carbon but because it does not take in C-14 from the enviornment as a living organism does.
Other radioctive dating systems go back hundreds of thousands of years.