The surface enamel of fetal bovine teeth was stained with GBHA to indicate the position of bands of smooth-ended and ruffle-ended ameloblasts relative to the developing enamel. The boundaries of the bands were scored, under a dissecting microscope, and the bulk enamel under each band was collected. The enamel samples were assayed for Ca, Pi, F, and proline. The amount of Ca and Pi in the enamel increased in successive bands and seemed unrelated to the overlying ameloblast cell type. The loss of proline seemed unrelated to cell type. The fluoride content of enamel increased by approximately 50% in the first stained band immediately adjacent to the secretory zone. The F level returned to secretory values in the succeeding unstained band. Thus, only changes in the F level of developing enamel appeared to be related to GBHA staining patterns.