Minnie Mae Clark-Capt. Wm Clark?

Hello,

My name is William Averill Frazier, the same as my father and grandfather . My grandfather was a coal miner who lived in Uniontown/Labelle south of Pittsburgh PA. His son William (one of many siblings) was born in 1918 so that would put my grandfather's birth somewhere about 1880-85 I think. Based on the name I suspect an origin in Scotland, Wales or England.My paternal grandmother's name was Minnie Mae Clark who may have been descended from one of William Clark's (of Lewis and Clark)offspring. Based on physical appearance of my grand mother and some of my uncles, there is a strong likelihood that Minnie May Clark was one fourth or more Native American (PC for Indian). I would also like to pursue this branch of the family but have no leads at this time. Thanks for your help.