What event finally caused southern states to leave the union leading to the outbreak of the civil war?

The election of Abraham lincoln caused the state's to secede

The most useful signs in identifying the sites left by the clovis is flaked stone points.the term clovis is used to identify the earliest culture to develop in north america. the clovis were found all through north america but its technology only lasted for a brief period of time. the sites of clovis range in age from 13,400 to 12,800 calendar years ago.