There are some Colf's listed in the 1818-1850 newspaper index
However, census shows that Erastus was born in the 1820s and that his father John was born in the 1780s. It is unlikely that a father William would have fathered John in the 1780s and lived until 1898. The name could have been a German KOLFF, or an English Coulf.
The LDS-IGI has an entry, William Colf, born 30 APR 1826 in Parma, Monroe, New York. That could be the man who died in 1898. The Parma cemeteries are given on: http://mcnygenealogy.com/cem/index.htm#par
but not all of them have been transcribed. There is a William Colf in the 1810 census of Hoosick, Renssalaer County, NY.