Hi !
Thanks for the info but Janvier Dupré was not born in NAdams but in Varennes, Québec, Canada.
Looking through immigration info I now believe that his wife Adeline Guillerie emigrated in NA, Mass and this explains his marriage there. How he became to know her might be explained by the fact that Dupré and Guillerie families had close ties ( my grand father Leopold, for example, married Romualda Guillerie, his cousin)