On the Rochester library site, you can find http://www3.libraryweb.org/lh.aspx?id=470901
, which is a partial index to the 1855 census of Gates Township. The names for Humphrey Hart and family appear on page 510 (with all of the information that was in the actual census). Their names do not appear in the 1818-1897 newspaper index. Your contribution in WorldConnect shows that you know her maiden name was Burdick.
The Gates town historian, Judy DeRooy, 1605 Buffalo Road,
Gates, NY 14624, (585) 247-6100) might have records that predate the official start of vital records registrations in 1880.
There are many newspapers in Rochester at that time and only one was indexed in the online index at:http://www3.libraryweb.org/lh.aspx?id=963
You can also check various digitized sources at:http://www3.libraryweb.org/lh.aspx?id=470901
, which include will, intestate estates , etc.