If you're asking about that line that starts just under Liberty and runs to God that looks like a Ridge Ring, which is the result of a die that's wearing out. As the die is smashed into planchets thousands upon thousands of times the outer edges of the die, where the forces are greatest, slowly deform, causing these rings to be left on the coins.
Ridge rings are pretty common on cents from the late 80's and early 90's.
Ridge rings are pretty common on cents from the late 80's and early 90's.






















