Is this the one, b 1844, parents John whiney and Mariah Boood?
https://www.familysearch.org/search/trees#count=20&query=%2Bgivenname%3A%22Mary%20Ann%22~%20%2Bsurname%3AWhitney~%20%2Bspouse_givenname%3AGeorge~%20%2Bspouse_surname%3ADowney~&collection_id=%282%203%29
FamilySearch, while it is well populated, often isn't totally accurate, as in this case it covers User Submitted Trees, which may not be well documented.