This picture wasn't sharp enough for me, so I originally didn't post it - BUT - thanks to Christine, I think I may have an ID.

Here's what she wrote to me: "The northern/pearl crescent complex is something that many butterfly experts disagree over. Some don't believe they are two species, one just a subspecies of the other. Up here, we generally look at the antennae and if they are orange we say they are northern. But even then they are difficult to ID, and some say the females cannot be differentiated in the field (needing microscopic work to tell the difference)."