I found a 1973 dime with no mint mark. It has that little thing below the year that I can't make out, but it has no mint mark above the year. According to this, it is one of the rarest kinds. I also found a 1967 quarter with no mint mark. Both can be seen here.
First, welcome to the neighborhood! One of the most frequent questions we have posted here by newbies is about "No S" coins, and most often these questions can be answered simply by looking in a copy of "A Guide Book of United States Coins". Chris
Did you happen to notice anything different about the coins listed in your "rarest kinds" link and the one you're asking about? Also, any "no mintmark" coin was highly valuable and desirable, didn't you wonder why you just happened to find two? I'm sure someone will take this as me being a meanie, as always, but both are perfectly reasonable and honest questions you should ask yourself.
