Data for the commoner trace elements in the rock and component mineral series of a differentiated teschenite sill are presented. The most important trace elements in the various mineral series are: olivines, Ni, Co; clinopyroxenes, Cr, Ni, Co, V, Zr, Sc, Sr; titanomagnetites, Ga, Cr, Ni, Co, V; plagioclase feldspars, Ga, Sr, Ba; analcites, Ga, Zr, Ba, Rb. With differentiation Cr, Ni, Co and V reveal the most extreme variation, both in the rock and mineral series; these elements are absent in a vein of microcrystalline mesostasis (approximating in its composition to analcite syenite) from the uppermost levels of the sill. Zr, Ba and Rb are enriched in this liquid. Fractionation crystallization is considered to have been the differentiation mechanism responsible for the variations in the rock and mineral series.