One genealogy chart has his name as Dr. Erasmus Willey; however, that is incorrect.
The ancestry of Erastus may be found in the following source: "Isaac Willey of New London, Conn., and his descendants" by Henry Willey; New Bedford, MA, 1888.
The children of Erastus and Hannah (Remington) Willey are listed on page 130 of the above-noted book (full text available online at Google Books).