My family includes a number of Beltrans from Rosario & Chametla. My branch moved to Mazatlan about 1880 from Chametla, but some Beltrans remained in Rosario, but I don't know about them. The earliest names from the 1700s include Nasario. Ysidro, Victor and many others. What other names have you? What dates pertain to each? Church records for Rosario are readily available.
Others include Lorenzo, Tomas, Matias and Juan Ramirez Beltran.
Regards, Ed Nissen Padillaedjeanne@mlode.com