Mineragraphic, chemical, and X-ray data are presented on the titanomagnetites¹ from a differentiated teschenite sill. The minerals are generally homogeneous. The earliest titanomagnetites are Fe₃O₄.Fe₂TiO₄.FeTiO₃ a solid solutions; the titanomagnetite crystallization trend is one of enrichment in Fe₃O₄ and FeTiO₃ at the expense of Fe₂TiO₄. The relations of the titanomagnetites to the parent rocks and associated minerals, and their role in basaltic magma iron enrichment are also discussed.