Many family trees on ancestry and elsewhere have Joseph Iliff as being married to Isabell Yates. According to readily available online records/books this is totally incorrect!
Today, too many people are quickly copying other people's mistakes without checking or double checking facts and end up posting erroneous information. Please do your own research!
Don't believe everything you see in someone else's tree. I know it's tempting to copy, but don't. Do yourself a favor and only post confirmed information.