I found a David Powless in the 1871 Ontario Census. Born about 1823. Religion:Anglican, Occupation: farmer, Origin: Indian, District: Hastings East (061), Sub-district: Tyendinaga. He may be your Grandfather. Have a look at the National Archives of Canada site: www.archives.ca, there is quite a bit of Powless info there and you can have copies made of the microfilm articles on file. Good luck.