First-baseman using a catchers mitt

Question
I recently attended a little game (major division).The first-baseman was using a catcher's mitt. When he fielded a ground ball and stepped on first base.The umpire awarded the running first base. His ruling was that the player was using an illegal glove. Rule 1.12 states that a catcher must use a catcher's mitt. Rule 1.13 states that the first basemen can use a mitt or a glove as long a it is not over 12 inches across. The umpire states that the first-basemen can use a mitt but not a catcher's mitt. Is he correct in this ruling?

Answer
Kelvin,

As long as the catcher's mitt followed all the dimensional requirements stated in Rule 1.13, then the glove is legal.  There are several dimensions laid out in that rule, so a catcher's mitt may not be legal.

I'm not sure the umpire ruled correctly, even if the mitt was illegal though.  First of all, the umpire probably should wait until the opposing team asks for a ruling.  Then, if the equipment is ruled illegal, I believe that the play is resumed from before the equipment is ruled illegal, so the batter would return to the bat, the glove would be removed from play, and the game would continue from that point.  Not sure about that, but I believe that's the rule.

Hope this helps!

Brian