I am very new at collecting errors and can tell you what little I know. The Cohen index by Jean Cohen is classification of errors on pennies. He published a book "The classification and Value of Errors of the Lincoln Cent". I could not find a website listing his description of errors, but that does not mean there is not one out there. I got lucky and found a book online to buy. The book illustrates the different errors and he gave them each a number. There are several different "Spiked head" varieties and each is classified with a different index number. Some of these other guys would probably be more help or search this website...I am sure the answer is here somewhere.






















