Julio Mercado - Jerez, Zac

Does anyone have any information on "Julio Mercado" born in the early 1800's in Jerez, Zac.? He was married to Francisca Pacheco Alvarado. I found several of their children's marriage and death records, but not their birth records because there is a gap in these church records from 1850-1866 in Jerez. The films on this site show a listing of these missing years, but I did not actually find these years' records in them. His death record lists his parents as "Gerardo Alvarado - not Mercado" and Eufemia Rodriquez, but I question this since that is the exact same name of the informants 'maternal' grandfather. I can not find any records of any kind for these parents; Gerardo and Eufemia. His age at death of 105 in 1916 is also questioned since he lists his age in earlier documents as being born in the late 1820's and/or early 1830's. I've hit a brick wall for years on this line. Cynthia