A THREE-YEAR FIELD STUDY ABOUT THE CULTURE BASED PATTERNS THAT ARE CAUSES OF THE ETHNIC CLEAVAGE CHARACTERIZING ANGLO-MEXICAN AMERICAN COMMUNITIES OF THE SOUTHWEST WAS CONDUCTED IN ROSARIO, CALIFORNIA (55 PER CENT MEXICAN AMERICAN AND 40 PER CENT ANGLO). THE SOCIAL STRUCTURE OF ROSARIO APPROACHES SIMMONS'"CASTE POLE" OF A RANKING CONTINUUM, DEMONSTRATED BY THE DIFFERENTIATION OF VILLAGERS ACCORDING TO ETHNIC IDENTIFICATION AND RACIAL OR PHYSICAL CHARACTERISTICS. THESE TWO CULTURAL GROUPS FORM STEREOTYPED BELIEFS OF EACH OTHER WHICH SERVE TO REINFORCE THE ETHNICALLY DIFFERENTIATED SOCIAL STRUCTURE OF THE COMMUNITY. IN GENERAL, THE ANGLOS PERCEIVED THE MEXICAN AMERICANS AS IMMORAL, VIOLENT, AND SUPERSTITIOUS, WHILE THE MEXICAN AMERICANS PERCEIVED THE ANGLOS AS UNSYMPATHETIC, AGGRESSIVE, HARSH, DEMANDING, AND INTERESTED ONLY IN THEMSELVES. THESE PATTERNED BELIEFS ARE TRANSMITTED AND SUPPORTED BY THE PUBLIC SCHOOLS AND CHURCHES OF THE COMMUNITY. SOCIAL RECONSTRUCTION IN THIS TYPE OF COMMUNITY CANNOT TAKE PLACE THROUGH A SINGLE AGENCY SUCH AS THE PUBLIC SCHOOL, BUT WILL REQUIRE APPROACHES THROUGH MULTIPLE ASPECTS OF THE TOTAL SYSTEM. (ES)