shield cent errors?

[Thorne]

Ive come across so many zincolns that it makes my eyes hurt. thought i would ask if anyone know of any errors that occurred during the making of these eye blinding zincs. I've read that some have die cracks that show up but not really sure what that means or what to look for.
Same subject different coin. speared bison nickels? what am i looking for with those? is it just a line through the bisons rear end

 

[enamel7]

There are doubled dies on all years of the shields, both obverse and reverse. There are also trail dies to be found. Not errors but varieties.

 

[sagittarius98]

speared bison nickels? what am i looking for with those? is it just a line through the bisons rear end

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