That is a really great image, tarpon! It looks like someone was experimenting with trying to overlay one date on top of another. I say "experimenting" because the overlay date is not from a particularly valuable year. If the overlay date had a "7" in it, I would suspect they might be trying to create an 1867 nickle...
I took the best pictures I could. The area around the date is raised. Could anyone inform me on what it is, and what caused it.
Thanks.
This is the result of a die crack/break.
It is a common thing on early nickels. Due to the hardness of nickel, the dies would crack or sometimes break.
The mint had trouble with making dies hard enough for a metal as hard as nickel, which is harder than they were use to working with. Metals such as copper, silver and gold are 'soft' when compared with nickel.