Thanks for the replies. I thought about exchanging them for a pair of Magma Mitts but instead decided to buy some Gordini Approach gloves from Campmor, which are made from Merino wool.
papedaler: Maybe you're right and I should have tested them on the bike before drawing any conclusions, but it sure did seem like the fabric was getting awfully cold just walking around, which didn't bode well for bicycling.