I've been studying a "collateral" line of our family that starts with Cornelius Porteous of Dunnington, Yorkshire, most likely born in 1784 in that village. Cornelius was most likely the brother of my ggg-grandfather, George Porteous, who was also born in Dunnington, in 1789.
I know from a Montreal Emigrant Society document of 1832 that Cornelius' passage (as well as that of his wife and 8 children) to Canada was assisted by the society. The document indicates that he was sent to Prescott (directly across the St. Lawrence River from Ogdensburg, St. Lawrence County, New York).
I have been tracing Cornelius' son, Robert (born in Yorkshire in 1813), and have only just now (May, 2004) learned that Robert and his wife Mary Ann (maiden name unknown) were married in Ogdensburg in the 1830s.
Robert and his wife moved to Toronto and later to Saginaw, Michigan where they both died (he in 1893 and she in 1905). The 1870 Michigan census indicates that all of their children were born in Canada.
Perhaps a number of Cornelius' children remained in St. Lawrence County... One of them might even be an ancestor of the person you are searching...
I maintain a Web site at www.novateq.ca/genealogy/ and try to keep it updated with any information I come across. You might wish to check it from time to time to see what else I've learned.