Question about 1870 3 cent piece

I was looking at this 1870 3 cent coin, when I noticed the rim on the lower obverse.
What would this be called? Would this be considered an error?

What would this be called? Would this be considered an error?


Don
U.S. Nickels Complete Set with Major Varieties, Circulation Strikes
U.S. Dimes Complete Set with Major Varieties, Circulation Strikes
U.S. Nickels Complete Set with Major Varieties, Circulation Strikes
U.S. Dimes Complete Set with Major Varieties, Circulation Strikes
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U.S. Nickels Complete Set with Major Varieties, Circulation Strikes
U.S. Dimes Complete Set with Major Varieties, Circulation Strikes
U.S. Nickels Complete Set with Major Varieties, Circulation Strikes
U.S. Dimes Complete Set with Major Varieties, Circulation Strikes