Are you sure of your grandma's location? My great-grandmother's maiden name was also Powless and she also married a non-aboriginal man. Her name was Minnie Louise Powless and his name was Henry Whitlow. They lived in and around the Brant and Toronto, Ontario areas. If these are the people you are speaking of and that's all the info you have Have I got a surprise for you!!! You can email me at email@example.com and I can send you a gedcom file with more info that you could ever go through. What was your grandparent's name that was the child of your GGrandmother Powless? This info could solidify the connection.